Post on 03-May-2020
VOLUME 4
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CHAPTER SEVEN - CAUSATION 3
7.1. Mr Vernon’s Knowledge of PSV 504
7.1.1. General
A matter that was extensively argued and certainly is an important
question in these cases is the state of Mr Vernon’s knowledge about the condition
of PSV 504 at the time of the accident. Assuming that Mr Vernon contributed to
the cause of the accident by seeking to restart Condensation Injection Pump A at
a time when the relief line from the pump was not available because PSV 504
had been removed from the line for service did Mr Vernon know that this was
the position. If he knew then this would go towards meeting the pursuers’ need
to establish that the accident was caused by Mr Vernon’s negligence. Of course
the pursuers’ case is not that Vernon was negligent by attempting to start the
pump when the valve was missing but rather that he had no knowledge of the
state of the pump and that this was due to his failure to carry out his duty to
inspect the worksite. If he had carried out such an inspection, they say, it would
have brought home to him that the valve was missing. The pursuers have a
delicate balance to achieve on this matter and this is due to the position taken by
the defenders. The defenders aver that if the accident happened because Mr
Vernon was attempting to start Pump A then he knew that what he was doing
was contrary to the Operators’ safety procedures so that his decision to start the
pump was a deliberate failure to follow good and prudent work practices and
consequentially was “wilful misconduct” as defined in the Indemnities. This
would free the defenders from any liability they may otherwise have had under
these. Thus this matter while by no means the only point in the defenders’
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defence is undoubtedly a pivotal point. Moreover it should be noted that it is not
critical to the defenders’ position that Vernon knew that the PSV was missing for
if he did not know this they say that his ignorance points to a deliberate failure on
the part of the Operators to institute and maintain good and prudent handover
and permit to work practices which could also point to “wilful misconduct”. Of
course the state of Vernon’s knowledge could have a bearing on the question of
whether or not he was attempting to start Pump A about the time the accident
happened. The pursuers’ position is not that Mr Vernon never knew about the
state of the valve during the evening of the accident but that if he had at some
point known then the information had not at the time registered in his mind or
that he inadvertently had forgotten about it at the time he made his decision about
Pump A. It was said that the thought uppermost in Mr Vernon’s mind towards
10pm on the evening of the accident was that the pump had been handed over to
maintenance for a 24-month planned maintenance and his concern was to
discover if any maintenance work had been performed on the pump which might
preclude taking the pump back into production. In any event since as Lead
Production Operator he ought to have known that the valve was absent he was
negligent if he began to start the pump and the pursuers have a prima facie right
to recover under the indemnities whether or not Vernon had actual knowledge
that the valve was absent. Accordingly the pursuers submit that provided that
Mr Vernon pressurised the pump when the valve was missing, if the defenders
want to claim that his conduct was wilful misconduct, they have the onus to aver
and prove this.
7.1.2. The Relevant Evidence
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One fact that was agreed by all the evidence of experienced operators was
that it was contrary to prudent and good practice to run a Condensate Injection
Pump with the safety PSV missing. Indeed it was accepted that no operator,
including Mr Vernon, would ever do such a thing. I think this evidence is
soundly based. The safety element in the situation is not difficult to understand.
The purpose of the PSV is to open to relieve pressure should there be a surge in
pressure above acceptable levels when the pump is running. Such surges occur
from time to time and if the PSV is not in place the increased pressure has
nowhere to go. The Safety Procedures include a proposed procedure for running
a pump in an emergency without its PSV. This would involve a person being
posted at the blind flange. None of the witnesses favoured nor indeed could
explain the advantage of this procedure and indeed the witness Mr Henderson
said that if it was applicable at all it was only applicable to apparatus with
two PSVs (of which Pump A was not one).
The witness Mr Bollands took over his duties as Control Room Operator
at about 5.15pm on 6 July 1988 and he replaced Mr Price. It should be noted that
all Production Operators rotate so that Mr Bollands was perfectly experienced in
the duties of a Production Operator. About the same time Mr Richard replaced
Mr Grant as the Phase 1 Operator. Mr Bollands saw Mr Flook and Mr Vernon
conducting their handover which took place at the Lead Production Operator’s
desk. He expected that matters of significance would at that time be recorded in
the Log kept on the Lead Operator’s desk. This was an A4 notepad. Either the
incoming Lead Operator was handed notes on this pad or he took his own notes
on the pad. The contents of these notes is not clear and it may well be that each
Lead Operator decided what he considered to be important and worth noting.
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Generally just before the shift turnover on the Day Shift was a busy time in the
Control Room because performing authorities would be returning their permits to
be cancelled, continued, suspended or whatever. The busy period usually began
about 5.30pm. This means that if Mr Rankin followed the usual practice with
regard to the valve permit which would have needed to be suspended overnight
then the probability is that Mr Vernon would have been asked to suspend it. If
on the other hand Mr Rankin had finished what he could do that day to the valve
at an early time and had taken his permit say at 5pm to the Control Room then it
may have been Mr Flook who suspended his permit.
When just before 9.45pm that evening Mr Vernon was informed that an
alarm had gone off which indicated that Pump B had tripped he went to assist
Mr Richard after having a short conversation with Mr Bollands. Then the JCP
Panel Alarm went off and shortly after this Mr Vernon returned to the Control
Room. The JCP alarm would be consistent with the tripping of the Condensate
Injection Pump and would indicate that the JCP level was increasing unduly.
Mr Vernon was informed that the JCP alarm had gone off and he also informed
Mr Bollands that he had unloaded and recycled the Reciprocating Pumps. This
procedure would relieve the pressure on the JCP Drum. Mr Vernon informed
Mr Bollands that he had been unable to get Pump B to restart and that he
expected that there was trouble with the lube oil system on the pump.
Mr Vernon then indicated that he would try and see if he could get Pump A back
from Maintenance and get it running. At this point he said nothing about PSV
504. Indeed Mr Bollands asserts quite categorically that he personally did not at
the time of the accident know that PSV 504 was not in place. Mr Bollands said
that if Mr Vernon was intending to run Pump A without its safety valve he would
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have expected him to discuss this. As he put it “it was such a drastic step”. He
thought that Mr Vernon would have valued his opinion. Mr Bollands also
thought that if such a decision had to be taken Mr Vernon would not have taken
it without recourse to his superiors. If Mr Vernon had radioed to his superiors
other operators with their radios switched on, like Mr Grieve, would have heard.
When Mr Vernon saw Mr Bollands within minutes of the explosion the first
thing he did was to ask Mr Bollands what had happened. This may indicate that
Mr Vernon himself did not associate the explosion with anything he had been
doing to the injection pump. Of course later Mr Vernon was killed. Mr Clark
was also adamant that Mr Vernon had not raised with him the matter of PSV 504.
Mr Clark was an experienced Lead Maintenance Hand and if Mr Vernon was
about to do something that was irregular and possibly risky one might have
expected him to take the opportunity of discussing it with Mr Clark. Equally it
can be said that if Mr Clark knew that the PSV was absent it might have been
expected that he would have mentioned this to Mr Vernon. Mr Clark also made
other significant observations. He declared that if he had known that the PSV
was off he and Vernon would never have started the pump and also that if the
valves were missing the electricity would have been immobilised from a second
source so that he would not have signed the red tags as he had.
The witness Mr Grieve who was down at the 68-foot level at the time of
the accident also says that he had no idea that the PSV was missing.
With regard to Mr Vernon’s character the witness Henderson said that he
had worked with Vernon for 8 years and found him to be responsible. He
accepts that it was very bad practice to run a pump with the safety valve missing
and says that if necessary the plant would have been shutdown to prevent that
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happening. Moreover Mr Vernon was hoping to get promotion and in that
situation I would wonder if he would be inclined to take a highly irregular step
that almost inevitably would be found out.
The Phase I Operator would normally know the work going on in his
Modules during his shift and certainly Mr Grant, the Phase 1 Operator during the
day shift on 6 July, would have known since he at one point helped in removing
the valve. Of course when he went off duty he may not necessarily have known
that the valve had not been replaced since until the last moment the valve fitters
were trying to secure a crane to replace the valve. The question, of course, is
whether or not he would have communicated the status of the pipe to the
incoming Operator, Mr Richard, at handover particularly if no work was to
proceed at the valve over the night shift and the valve calibration was being done
in conjunction with the planned maintenance. On the other hand the fact that the
planned maintenance was proceeding was something that he certainly would have
been expected to mention. This does not however mean that he would have
thought it necessary to communicate to Mr Richards what was happening to the
PSV since the pump had passed out of the control of operations and was with
maintenance. Moreover as I have said he may not have known the precise
position regarding the PSV.
Mr Rankin gave evidence to the effect that after 6pm he met Mr Smith in
the accommodation module. He describes Mr Smith as his Maintenance
Supervisor which is incorrect in that he was the Maintenance Lead Hand.
Mr Rankin was right in thinking that as the employee of a specialist contractor he
should report to the Maintenance Supervisor but of course he got the wrong man.
Mr White was his proper supervisor and from Mr White’s lack of response when
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Mr Clark got his telephone call shortly before 10pm, it can perhaps be assumed
that Mr White did not know the state of the PSV. Mr Rankin was possibly
confused in that Mr Smith had assisted him to get started with the valve in the
morning and as he had only recently begun to act as a Score Supervisor he may
not have been as familiar as some Score employees with the personnel on the
platform. Mr Rankin claims to have returned his permit to work to the Control
Room (although he is vague about the detail of this) and then to have visited the
Score container before proceeding to the Accommodation Module where he met
Mr Smith. I have no reason to doubt that the encounter with Mr Smith took
place and since the circumstances are such that it can be assumed to have been
after 6pm, when Mr Smith was off-duty, we have one time reference that can
perhaps be relied on. Indeed another witness Mr Mochan confirms, at least to a
degree, the time of the meeting. It would appear that Mr Smith had gone off-
duty about 5.45pm and before meeting Mr Rankin in the recreation room would
have required time to make a telephone call and to have changed out of his work
clothes. Mr Smith asked Mr Rankin if blind flanges had been fitted and the latter
confirmed that this was so. It is perhaps unfortunate that Mr Smith did not also
ask Rankin if he had reported to Mr White but it would perhaps be
understandable if he just assumed that this normal procedure would have been, or
would be, carried out. This confusion may also reinforce Mr Clark’s claim that
he had no opportunity to find out about the state of the PSV. Also if Mr Smith
did not know what had happened to the valve before he went off-duty (he may
well not have known that the work had not been completed if indeed he knew
that the permit had ever been issued) then it is unlikely he would have mentioned
the situation during his handover with Mr Clark. Thus whatever Mr Vernon’s
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paths to knowledge about the position regarding the PSV it is unlikely he gleaned
any information about it from Mr Clark.
The evidence of Mr Rankin may be of crucial importance in relation to
Mr Vernon’s knowledge of the valve work. Mr Rankin was uncertain in some of
his evidence and this is perhaps not surprising. He had survived a dreadful
accident which had killed his workmate Sutton. Then he finds himself associated
with the critical events said to be responsible for the catastrophe. Moreover the
accident happened shortly after he had become supervisor which of course must
have added to his concern. Prior to the accident Mr Rankin had been employed
by Score for about two years as a valve technician and had previously been
employed by Otis Pressure Control. Thus in a general sense he had reasonable
experience of valve maintenance operations. Before the accident he had worked
on valve related work on Piper Alpha and other offshore platforms. He had
worked on Piper Alpha for about 6 weeks during March 1988. However during
that period he had not been acting as supervisor. He was appointed to that
position on the day before returning to the platform for the tour of duty that led
to the accident. He had not acted previously as supervisor. Mr Sutton and he
began their tour on Piper Alpha about 27 June 1988 and their tour was expected
to last about 4 weeks. Before the accident he had on that tour maintained about
10 valves. He claimed, and I can accept it, that it was a routine job to fit blind
flanges. Yet at one point in his evidence he indicates that he cannot ever
remember having been involved in the fitting of valves to open-ended pipework.
Before he came to Piper Alpha as supervisor he had no experience of operating
the permit to work system on the platform. He realised quite clearly that his
function as supervisor included being responsible for following the permit to
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work procedure, to refurbish and certify the valves, and to oversee the work. In
dealing with the permit to work situation he was helped by the fact that in the
Score Container a list was posted indicating the various steps which had to be
taken to follow the permit to work procedure. There is no doubt that he
appreciated that the permit to work procedures were important for the regulation
of safety. However it might appear that the specific instructions which his
employers gave him about the detail of the permit to work system were fairly
skimpy. He was given no specific instructions about the fitting of blind flanges.
However he knew that blind flanges always required to be tightened with a
flogging hammer or combination spanners. His view of the function of a blind
flange was that it was attached to prevent accidental spillage from the system or
to prevent dirt getting into the pipes. Since he must largely have acquired this
knowledge while working as an ordinary valve technician this is an indication of
what such a person might have been expected to appreciate about the fitting and
the function of blind flanges.
When Mr Rankin began his tour as supervisor he was introduced to
Mr Todd who asked him about his knowledge of the permit to work system.
Mr Todd was presumably satisfied that Mr Rankin knew sufficient about the
system. Mr Rankin had informed him that he had no problems with this and that
he had run through it with his own supervisor.
Mr Rankin claimed possibly to have had experience in the suspension of
permits to work but his evidence in this respect was distinctly vague. However
the documentary evidence shows that at least on occasions during the tour
Mr Rankin had suspended permits or had them extended.
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Mr Rankin’s shift began about 6 am and was due to run until 6pm.
Normally a valve would be completed during the one shift. Once a permit had
been issued for Mr Rankin’s work he would be given a copy of the permit. He
claimed that he would have kept it on his person which is not exactly how he
should have dealt with it.
The defenders argue that the evidence shows that matters involving the
extension or suspension of permits would normally be handled by the incoming
Lead Production Operator and they are right about this. Of course the practice
would assume that there would be an incoming Lead Production Operator
recently come on duty when the suspension or extension was required. Thus
were it the case that Mr Rankin had brought the permit back to the Control Room
at 5pm it would be consistent with the evidence that Mr Flook would have dealt
with any suspension required at that time.
There was evidence which was not disputed that it was not unknown for a
pump which had been withdrawn for planned maintenance to require to be
brought back to service and the defenders found on this as indicating that the
Lead Maintenance Operator should have had this in mind when apprising himself
of the working conditions on the platform. It was certainly part of his duties to
be familiar with the running of the plant during his shift. He controlled it on the
floor of the platform. As we were told the tripping of a pump is not unusual and
that may have been why Mr Seddon when he telephoned the platform from
onshore was rather uneasy about doing the planned maintenance.
In relation to Mr Vernon’s state of mind when he went to restart the pump
it is certainly most unfortunate in every sense that he did not live to give his own
account of the facts of the night of the accident for which he is being blamed.
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However Counsel for the defenders maintained that the test of a person’s state of
mind would in any event have to be decided on the objective data. He referred
me to Walker and Walker “0n Evidence” where at par. 24 the authors say that a
party’s state of mind can be proved only by inferences drawn from other facts so
that the circumstances associated with these facts are relevant and admissible
evidence. I did not understand that this expression of the law was disputed. Of
course there may be many cases unlike this one where direct evidence of a state
of mind was available but even in such a case the reliability of the witness as to
that would have to be assessed by reference to evidence of the other facts and
circumstances. Nor do I have any difficulty with Mr Keen’s argument that if the
proved facts would have conveyed the necessary knowledge to any reasonable
person then the required knowledge will be imputed to the relevant person. I
was also referred to some of my own dicta in the wilful fireraising case of John
Scott Blane v HMA 1991 S.C.C.R. 576 where I observed:
“however, since we cannot see into the fireraiser’s mind his intention
must be derived from the objective circumstances surrounding the
incident. A man will be presumed to intend the natural and foreseeable
consequences of his acting ... a reckless indifference to the consequences
of a deliberate act of fire raising can be taken as equivalent to these
consequences being intentional”.
That quotation deals of course with intention to be attributed to actings and not
with state of knowledge. However the problem in this case is not the law on this
matter but the difficult “Jury” question of ascertaining what the surrounding facts
were and what inferences can be taken from them. Defenders’ counsel’s point
was of course that since Mr Vernon must be taken to have been a reasonable man
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then from the facts known he must be presumed to have been aware that Pump A
was lacking its PSV. However the problem is compounded by the fact that the
issue is not what Mr Vernon may have known at some time but whether or not he
retained that knowledge at a particular time.
The defenders also made a submission that far from being pressed for
time Mr Vernon had plenty of time to take alternative measures. He had over an
hour before the Suction Condensate Vessel would overflow to flare. The de-
isolation of the electricity would involve some time because this involved the
identification of the tags and the relevant keys, the retrieval of the keys from the
key safe, the removal of padlocks and the return of the racks. This would have to
be done not only for the motor but for the lube oil system as well. These would
have required about 15 minutes. However the argument was continued by the
defenders to the effect that there was not such an emergency that an experienced
Operator would have thrown caution to the wind. If the word “deliberately” is
added I doubt that the pursuers would disagree with that sentiment. The
defenders placed great emphasis on the fact that for Mr Vernon not to be aware
of the PSV’s absence he would have to have ignored or not absorbed not one
factor but a great many. The Defenders summarised these as being, firstly, that
the PSV permit would have been suspended at the end of the day shift and it is
clear that it must have been Mr Vernon himself who suspended it. Secondly Mr
MacGregor had a permit suspended at about 9.15pm on the evening of the
accident. It would have been Mr Vernon’s duty to inspect this worksite at the
point of suspension and this site was close to where PSV 504 should have been
located. In fact Mr MacGregor’s work had been to fix a plate to the Suction
Scrubber near the scaffolding which had been erected for the PSV removal.
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Thirdly there were many people directly in contact with Vernon who would have
known about the PSV maintenance. Fourthly it was said that even if Mr Vernon
did not himself suspend the PSV permit at the shift handover he would have
known about it assuming that he had followed the other safety procedures.
Fifthly the events in the Control Room just before the explosion suggest that Mr
Vernon must have known about the position regarding the PSV. I do not think
that there is any doubt that it was Mr Vernon’s responsibility to keep himself
informed of features of the process which may have affected safety. If anyone in
management should have known about the status of the PSV it was he.
The pursuers themselves make averments in their pleadings which the
defenders said are important to the resolution of the problem being considered.
They aver:
“It was the duty of Robert Vernon to have the worksite checked in terms
of the Permit to Work procedures then operating on the installation.
Robert Vernon had not checked said work site prior to the initial
explosion. Had he inspected the work site he would have become aware
that PSV 504 had been removed and had not been replaced. In that
respect Robert Vernon was negligent and so contributed to the accident”.
The pursuers argue that the defenders originally denied these averments and only
admitted them by amendment at a late stage of the proof. Thus at the relevant
time the pursuers had simply not proved these averments which at the time they
led relevant evidence were in dispute. It is of course obvious enough why the
pursuers made these averments since they were anxious to show that they had
little choice but to make compensation payments to the victims. The question
remains if they have at the same time established one of the defences to the
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application of the indemnities by themselves apparently accepting that the
accident was caused by an intentional departure from good and prudent practice.
This is certainly the defenders’ contention and indeed they say that since they
have admitted the averments in question these must be taken as among the
established facts in the case. In terms of the permit to work procedures the Lead
Production Operator in his capacity as Designated Authority has an obligation to
satisfy himself with the job site in the event that he is responsible for the
suspension of the permit (paragraph 3.6(a) of the permit to work procedures in
the General Safety Procedures Manual number 12/405 of process). However it
must be noted that the responsibility on the Designated Authority is not
specifically to inspect the site but to “satisfy himself”. Whatever the pursuers
take to be the import of the rule about the procedure to be followed upon
suspension there is little doubt that in practice not all the operatives considered
that it was necessary to carry out an actual inspection to satisfy themselves about
the worksite. Thus Mr Henderson thought that it was sufficient to satisfy oneself
by indirect inquiry and that an inspections would only be necessary if there had
been serious work carried out such as breaking into the condensate system. On
that view what would be a reasonable procedure to satisfy himself may vary with
the particular circumstances. Thus in the case of an absent PSV it may be a
sufficient safety check to inquire if blind flanges have been fitted particularly if
the pump has already been isolated. In any event it is by no means clear that a
Lead Hand who did not carry out a physical inspection would consider that he
was violating the safety procedures. Mr Snape thought that upon suspension it
was the duty of the Lead Production Operator to inspect the site but he may not
have been as familiar with the Rules on this point as the production operators
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who were following the system from day to day. The matter of the blind flanges
seems to have been Mr Smith’s only concern when he spoke to Mr Rankin in the
recreation area. In any event whatever the wording of the Safety Procedures the
procedure followed on the platform seems to have been that granted that it was
often impracticable to inspect a site it sufficed in many cases simply to be
satisfied that the site had been left safe. Applications for suspension of permits
were likely to be coming in thick and fast at or about the changeover period. In
any event there is a fundamental illogicality in the pursuers’ averments on this
matter. If Mr Vernon did have a duty to inspect the worksite this could only be
because he was aware that the valve work had been proceeding. Since no-one
suggests that he had been asked to cancel the permit it is intrinsic to the situation
that he knew that the work had not been completed. If he knew this then it is not
likely that on inspection he would have discovered anything he did not know
before the inspection. In any event in relation to the Court’s attitude towards
implied admissions the pursuers referred me to Charles Lee v The National Coal
Board 155 S.C. 151 and Wilson v Clyde Rigging and Boiler Sealing Co. &c 1959
S.C. 328. I do not find it necessary to examine the implications of these cases.
In any event no attempt was made by the defenders to have excluded evidence
that showed that the alleged admission was totally inapplicable to the facts. Even
if an admission on Record is to be regarded in the same light as evidence (as
Lord Sorn suggests in Lee at page 160) if further evidence is without objection
admitted to the proof which contradicts it then the Court must assess the whole
evidence. Cancellation of a permit (as distinct from suspension) involves a duty
to inspect the worksite but the permit to work relating to PSV 504 would only
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have been cancelled if the work on the valve had been completed and it is one the
uncontested facts in this case that the work had not been completed.
It should perhaps be noted that when Mr Todd the Maintenance
Superintendent was asked if it was good practice to run the Condensate Injection
Pump with the PSV missing he had no hesitation in saying that it would not be
good practice. Mr Clark was somewhat ambivalent about his own knowledge of
what would be bad practice on this matter but given Mr Todd’s position I think it
can be assumed that Mr Clark as a Lead Maintenance Hand familiar with the
equipment would well know that it was not satisfactory to run the pump in the
absence of an important safety feature such as the pressure relief valve.
On the matter of signing-off electrical de-isolation tags although Mr
Clark was not entirely consistent about this I think it is clear that as Maintenance
Lead Hand he had authority to sign these tags albeit that he was not the
Designated Authority on the permit. The production of documents relating to
such de-isolations establishes this.
One matter that may affect the evidence of Mr Bollands to the effect that
on the day of the accident Instrument Technicians had been working on Pump A
under the planned maintenance permit is that it seems undisputed that on the day
preceding the accident Maintenance Technicians had been working on Pump B.
In his memory Mr Bollands could have got the two pumps confused. On the
other hand if such technicians had been working at Pump A during the preceding
shift Mr Clark would not have had direct knowledge of this since he would not
have been on duty.
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It should also be noted that extending a permit does not require any
inspection. Upon a handover any suspended permits are handed over in a
separate pile.
If two permits relating to the same equipment were issued then there was
evidence that they would be folded together but this did not necessarily happen if
the permits related to work at different platform levels and given the system for
grouping the permits this would make sense. Moreover it was not made clear
that say a live permit or a permit application would be folded with a suspended
permit. Certainly Mr Bollands never referred to seeing two permits in
Mr Vernon’s hand at any time. In any event the defenders argued that if there
was only one set of electrical isolation tags then this must have related to the
PSV permit. This is based on evidence that the planned maintenance permit had
not been issued and evidence that electrical isolations would not be carried out
until the work is about to begin. The pursuers made the point that it had not been
proved that the replacement of the PSV actually required electrical isolation.
Certainly the evidence was that only some designated authorities required such
isolations for PSV work. Indeed were the position with regard to electrical
isolations critical to the defenders’ attempted reliance on the exceptions in the
Indemnities it has not been proved that the calibration of the Pressure Safety
Valves invariably led to such isolation although I would accept that it often did.
There was evidence that when the air lines to the pump were disconnected
a tag saying “do not operate” is attached. It was suggested that if Mr Vernon had
attempted to restart the pump he would have seen these tags. However since his
objective was to take the pump out of maintenance I am not quite clear how it
can be assumed that he would be deflected by the tags.
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It was argued by the defenders that the pursuers cannot challenge
Mr Clark on the matters contradicted by Mr Bollands because they did not
challenge either witness. However the defenders did not object to any evidence
from Mr Clark on the basis that it contradicted evidence which the pursuers had
led and not challenged. They were prompt to make such challenges on other
occasions and if a party has been misled by a pursuer’s approach to a witness this
may be a good ground for objecting to an attempt to lead contradictory evidence.
This arises on the basis of failure to give fair notice of the case being developed.
However in the case of Mr Clark’s evidence far from claiming prejudice the
defenders came to adopt and rely upon much of his evidence. In any event where
witnesses are giving evidence on relatively small matters of detail where from the
circumstances recollections might be expected to be unreliable about such detail I
am inclined to think that there is nothing irregular in not challenging all such
material. In such a case the integrity of the witness is not being challenged and
the point is often not whether a concession might be rung from the witness but
whether at the end of the day one version of events more closely fits other
evidence than another. Thus for example Mr Clark indicated that the electrical
isolations were taken out not for the PSV but for the planned maintenance and
the defenders themselves did not appear eager to challenge Mr Clark on this and
other aspects of his evidence. Mr Clark could hardly have supposed that the
electrical isolation tags had been referable to the PSV contract since he claims
that he did not know about this and yet at handover he was obviously told about
the electrical isolation. When Mr Vernon telephoned him he did not say “I do
not know what you are talking about. The permit application is in the Safety
Office and in accordance with practice there would be no red tags attached to it
735
until the work is about to begin”. His attitude would only be consistent with a
belief that electrical isolation tags were already attached to the permit application
since he seems not to have known about any PSV tags. The point made may rise
more sharply if one is left only with contradictory evidence from the witnesses
whose evidence is under review. Then if neither witness has been cross-
examined it may well be inappropriate to prefer one witness to the other if there
is no other evidence on which a decision can be based. However I need reach no
conclusive view on the technical point made for in my opinion it is
misconceived. Mr Bollands not only gave his understanding of the status of the
Planned Maintenance permit but actually claimed that he had read it. This is at
the core of his evidence and it is true that the pursuers did not challenge him
about this. Mr Clark did not for his part say that he had seen an unissued planned
maintenance permit in the Safety Office or indeed anywhere else. What he
founded his opinion on was the evidence that Mr Smith had told him that the
permit was not issued. He came after Mr Bollands (who was not cross-examined
by the defenders) and the pursuers at least to a degree challenged Mr Clark’s
assertion that the maintenance permit was never live. Unfortunately Mr Smith
did not survive the accident so that the account Mr Clark gave of his conversation
with Mr Smith could not be challenged nor could the basis for Mr Smith’s
information be tested. In these circumstances the pursuers may well have
decided that there was little point in challenging Mr Clark’s evidence as to what
he had been told. There is of course a division in the evidence as to whether Mr
Vernon saw Mr Clark in the Control Room and one or other of the two persons
who spoke about this must be mistaken. As I have already indicated it would
certainly be difficult to decide between them on this point so that it is fortunate
736
that it does not matter. It may also matter little whether the red tags remained on
a permit at the time when Mr Clark signed them or whether they had earlier been
detached by Mr Vernon. These incidental details are exactly what one might
expect a witness to be mistaken about.
The defenders submit that Mr Bollands must be wrong in suggesting that
instrument technicians were working on the pump during his shift because
evidence was given by the night technicians that contradicts this. However it
would not be at all difficult for Mr Bollands to confuse technicians working
towards the end of the day shift with technicians working in the evening.
Whatever else is clear it is that Instrument Technicians were not working on
planned maintenance of Pump A when Mr Vernon came down to investigate
pump B. Certainly Mr Clark said that no work had been done on the pump that
night and this therefore could be true in relation to the night shift. On the other
hand Mr Bollands is very certain that Mr Vernon took the pink permit with tags
on it from the box of active permits for the 68-foot level. Two details are
particularly important here. Firstly if the permit to work had related to the PSV
it would have been a blue permit. Secondly if the permit had related to the valve
maintenance then it would have been kept at the 84-foot level slot and not that
for the 68-foot level. It is perhaps unlikely that Mr Bollands would have been in
error in respect of both details. Of course he might be mistaken about the detail
but if he is right it is difficult to see why a revalidated permit relevant to the
situation was in the live permits box unless some work had indeed been
proceeding under it. As the timings may help to clarify whether or not Mr Clark
saw Mr Vernon in the Control Room I think they would permit the view that an
737
encounter there was perfectly possible. On the other hand as I have said I do not
find it critical to reach a concluded view about that fact.
The pursuers referred me to authorities aimed at assisting me to arrive at a
solution to the problem of witnesses who may give conflicting evidence about
factual questions. The first case they referred to was Keenan v Scottish Co-
Operative Society Ltd 1914 S.C. 959. In that case (which was a jury trial)
three witnesses had given important evidence for the pursuer but the defenders
led conflicting evidence which was not cross-examined. It was held that the
pursuer must be held to have conceded the veracity of the account given by the
defenders’ witnesses. The pursuers distinguished that case on the basis that on
the vital matters they had cross-examined Mr Clark. Moreover, of course, there
is the fact that both witnesses were led by the pursuer and in circumstances where
it might be conceded that each was trying his best to remember detailed events of
some complexity in circumstances where genuine lapses of memory might be
expected. The other case cited by the pursuers was Margaret Robertson or
Stewart v The Corporation of Glasgow 1958 S.C. 28. This was a reparation case
where one expert had examined a pole which had caused the accident and was
not cross-examined on his views. The second expert had not examined the pole
but on the technical questions agreed with the first expert on the basis that he
accepted the results of the latter’s examination of the pole. A question arose as
to the corroboration of the condition of the pole and the pursuer sought to
corroborate this point from the fact that the first expert had not been challenged.
It was held that failure to cross-examine a witness did not supersede the need for
corroborative evidence on the point under discussion. It should be noted that the
case was concerned with credibility in relation to a critical matter. If one were
738
applying the above cases strictly then the fact is that it was the defenders in the
first place who accepted the evidence of Mr Bollands without challenge. The
defenders in other words did not challenge Mr Bollands credibility. They
accepted that he was trying his best to remember detail of the important events.
In cases of this sort one can understand why Counsel may hesitate to suggest to a
witness that he is not credible. Counsel for the parties were prepared in general
to accept that each witness was doing his best to tell the whole truth and to base
any criticism of the accuracy of a witness on other evidence of detail. In any
event what the pursuers argued is that the evidence of Mr Bollands and of Mr
Clark can largely be reconciled. This is true and even if there is divergence on
matters of detail these do not destroy the pursuers’ position in relation to Mr
Vernon. On the really essential matters the evidence is sufficiently consistent
particularly upon matters that were not challenged with Mr Clark.
One fact beyond doubt is that shortly before the accident occurred
Mr Young the instrument technician had been summoned to the 68-foot level.
The defenders say this shows that by that stage Mr Vernon’s intention was to
restart Pump B. Certainly it can be argued that a Instrument Technician might
well be of more service in starting the pump which had tripped rather than the
pump to be retrieved from the maintenance programme. On the other hand the
fact that Mr Vernon was trying to get Pump A started would not preclude
continuing efforts to trace the trouble in pump B and get it in working order
again. Further Mr Vernon had expressed the view that the trouble with Pump B
was in the Lube Oil system which would not require an Instrument Technician to
cure. The fact is that in my view Mr Young’s summons does not advance
matters significantly.
739
There is certainly no evidence that there was any talk of suspending any
planned maintenance permit before doing any work restarting Pump A. If
Mr Clark had been presented with an issued planned maintenance permit one
would have expected that he and Mr Vernon would have suspended this permit
when they signed the tags. Neither Mr Bollands nor Mr Clark speak to that
happening. Thus either Clark is right when he says he was only given tags or at
least he is right when he suggests that the permit had never been issued.
In relation to the question of timings I have already in Chapter 5
discussed these at some length and I have also there elaborated on my views as to
whether or not a permit to work for the pump had been issued. The question is
difficult and although the evidence that the permit had in fact been issued is
marginally stronger as I have already stated I am not sure that the matter is one
which impinges critically on Mr Vernon’s state of knowledge.
7.1.3. Mr Rankin’s Part
In relation to the work he had done earlier in the tour Mr Rankin thought
that generally he had been working on plant with more than one PSV available to
it. The valve fitters could not work on a valve on a line which was in production
and accordingly they had to wait until a particular piece of equipment became
available. This is what happened with PSV 504. In the morning of 6 July
Mr Rankin was told by Mr Smith that PSV 504 would be made available to the
valve technicians during the day. It was the last valve they had to attend to
before their tour of duty ended. Mr Smith mentioned that there would be further
ongoing work on the pump which would allow the removal of the valve for
maintenance. The conversation with Mr Smith took place in the Maintenance
740
Lead Hand’s Office which was close to the Maintenance Superintendent’s Office.
The timing of the conversation with Mr Smith is not exactly clear but we do
know from Mr Lynch that by about 7.15pm Mr Smith knew that he would be
getting Pump A for maintenance and that he had applied for the requisite permit.
This timing is vouched by the fact that Mr Curtis signed the permit about
7.40 am. Mr Rankin came to the Control Room just after 8 am to inquire if he
could get the valve without a separate permit. This fact itself may reflect his
relative inexperience. Mr Rankin stated that after he got his intimation from
Mr Smith he obtained a permit form for the PSV from his Container Room
which he thought had been filled in by Mr Whalley the preceding Score
supervisor. He is again vague about the details but seems to remember that some
information had already been filled in.
After procuring the permit application Mr Rankin indicated that he took it
to Mr Curtis for approval. It is perhaps also a measure of his lack of familiarity
with the procedure that he had to consult his check list before taking this step.
Mr Rankin was able to confirm that the application was for a cold work permit.
Mr Rankin does not remember at any stage going to Mr White to have the permit
requested. Of course Mr Smith may have taken this step for him. Mr Curtis is
unlikely to have signed the application until Mr White signed it and although the
copy permit application which was recovered and produced (number 12/233 of
process) does not show any decipherable indication of Mr White’s signature this
may be because it had been damaged in the catastrophe. In the case of permit
applications the Approval Authority keeps a copy and this is the copy that was
produced. It was recovered from the accommodation area of the platform wreck.
As Mr Rankin proceeded with his evidence the impression that he had little
741
recollection of certain details was reinforced. Mr Lynch speaks to the fact that
Mr Rankin came to see him between 8 and 9 am on the morning of the accident
and mentioned that the Condensate Injection Pump would be available that
morning so that he wanted permission to do the valve work. Mr Lynch sent him
to Mr Smith to get the necessary paper work attended to. Mr Rankin does not
remember any visit to the Control Room that morning but I have little doubt that
Mr Lynch has a more accurate recollection. He also had Mr Flook there at the
time of Mr Rankin’s intervention. One problem however with Mr Lynch’s
account is that the copy permit shows a signature of the Approval Authority
which purports to have been appended at 7.40 am so that Mr Lynch may not be
accurate as to his timings, or as he suggests, Mr Smith may have taken the
application for a permit to Mr Curtis at an earlier time. Mr Lynch does not
remember seeing the completed application before he withdrew about 9.45 am to
leave the platform so that if anyone signed the permit as Designated Authority it
must have been Mr Flook who unfortunately did not survive the accident. Even
if the permit application had been presented to Mr Lynch he would not have
signed and issued it until the isolations were complete. In fact it is unlikely that
any permit would have been issued until the pump was ready for handover in the
late morning or early afternoon.
Mr Rankin does remember that after he had obtained a signature from
Mr Curtis he experienced further delay because he needed to arrange for a
scaffold and this may be the sort of detail which stood out sufficiently in his
memory to be retained. He did not remember going to the Control Room to have
the permit issued but agrees that he must have done this. On the other hand he is
not entirely consistent about this because at certain stages of his evidence he
742
claims that he took the permit to the Control Room in the morning. Moreover,
however restricted Mr Rankin’s experience may have been he was certainly
aware of the need to obtain a permit to work and I think it unlikely that he would
have embarked upon the work without such a permit. This view is enhanced by
the fact that an application for a permit was signed by Mr Curtis. If he got a
permit then a copy of this as a live permit would have been retained in the
Control Room and the Lead Operators would have expected some procedure
relating to this to be followed at the end of the shift. Thus Mr Vernon would
have been expected to know something about the permit when he came on duty
supposing of course that the permit was actually issued. Even if Mr Rankin had
not been available as a witness I should have been reluctant to believe that he so
flagrantly breached his obligations as to carry out work without any permit
unless there was at least some evidence to suggest this possibility.
Assuming then that he had his permit Mr Rankin then had to address
himself to the removal of the valve. Since the scaffolding permit could be issued
before the permit for the valves I think it is reasonable to suppose that Mr Rankin
had arranged this at some time during the morning as his vague recollection
supports. Mr Grant gave him some help and he remembers Mr Grant closing a
valve in Module C which was close to the deck level. This does not make too
much sense because the only valve in Module C which Mr Grant may have
closed was the Manual Isolation Valve for PSV 504 which was close to the PSV
and some height above the deck. Mr Rankin thought that it was about 2pm when
he began to remove the valve. He said that it was after lunch, that Peter Grant
was available, and the valve was removed. The procedure followed for this is
that the nuts would first be open at either side to see if gas is escaping. Once the
743
nuts are loosened the rigging is put on the valve, the bolts are extracted, the valve
suspended and then it is lowered to the deck. The blind flanges are then put on
and until this is done the pipework is open. The practice seems to have been to
release the nuts slowly to ensure that no gas is escaping and this is done in the
presence of an OPCAL representative to ensure that there is no sudden escape of
gas. Just what the OPCAL representative was supposed to do in the event of an
escape was never made clear. Mr Rankin stated that his job in the operation in
question was to remove the nuts and bolts and then he could depart. He
remembered that a rigger was present and the valve was taken from the module
on a small trolley to be carried further by crane. As another illustration of his
bad memory Mr Rankin could not remember if he had participated in the
removal of the valve outside the module. He remembers the crane coming and
lifting the valve to the Score Container. He cannot remember how the services
of the crane was secured and indeed his recollection of the valve removal is
seriously flawed. However Mr Rankin seems to be certain that he personally had
loosened the bolts holding the valve. Then he had gone off leaving Mr Sutton to
fit the blind flanges.
Some evidence about the valve removal was given by Mr James
McDonald. He was aged 56 years and was a rigger employed by Wood Group.
This witness speaks to a fellow rigger Rutherford assisting Mr Sutton with the
valve. Unfortunately because he was medically unfit to give evidence
Mr Rutherford did not appear at the proof although neither party made any
attempt to introduce his recollection by way of hearsay except in one respect.
The witness McDonald said that he had discussed with Rutherford the timing of
when the work on PSV 504 was carried out and Mr Rutherford’s recollection was
744
that the work had not begun until the afternoon. It was Mr Rutherford and not
McDonald who was directly involved in the work. Mr McDonald had himself
assisted Mr Sutton on other occasions. Mr McDonald claims that about 8am
Mr Sutton came to him in the Gas Module and asked for help in the removal of a
valve. This timing must be wrong since the pumps had to be run and Pump A
de-pressurised before any work on the valve could proceed. Mr McDonald was
not free to assist Mr Sutton at that time but he sent another colleague. When
Mr McDonald visited Module C later in the day the valve was already down on
the deck and the only persons at the scene were Mr Rutherford and Mr Sutton.
That is to say Mr McDonald confirms that at that stage Mr Rankin was not
present. Again the timing is doubtful for Mr McDonald claims that his visit to
Module C was at “dinner time” which he said was about 12 o’clock. The meal
lasts for about an hour and cannot be taken late. The valve was put in a barrow
and taken outside the module to be moved further by crane. If Mr McDonald’s
recollection is accurate it is perhaps rather surprising that Mr Rankin was not
present supervising when the valve was being transported outside but there may
of course be some explanation. Mr McDonald was initially adamant that he had
only gone for his “dinner” after he had attended to the transport of the valve and
he thought that this operation would have taken about 20 minutes. Later
however he was prepared to admit the possibility that his timings could be
wrong. It would have taken about three hours to calibrate and quality test the
valve after it had been taken to the Score Container. The whole job of removing
the valve from its initial location on the deck and transporting it to the Container
may have taken about half an hour. Mr Rankin states that the work on the valve
did not begin until after lunch but he is not a reliable witness on matters of detail.
745
Like Mr McDonald he accepted that he could have been wrong on matters of
timing. A starting time after lunch would certainly be more consistent with the
time needed to test Pump B and isolate Pump A before work on the valve could
commence.
It should be noted that Mr Rankin never returned to the valve site to
check the blind flanges after they had been fitted. I do not say he was remiss in
this respect for the matter is not raised but of course it does mean that if the
flange had been fitted improperly no-one would have noticed. He remembered
the OPCAL Quality Assessor coming to the Score Container to check the valve
about 5.30pm. If Mr Rankin is more or less right in relation to timings this
would mean that the valve was ready for replacement about 6pm whereas with
Mr McDonald’s timings it could have been ready by 5 o’clock or earlier.
Mr Rankin claims that when the valve was finished it was quite close to
the end of the shift and that may be the sort of detail he would remember. He
claims that he remembers that he returned the permit to the Control Room and
thought that this happened about 6pm. He had gone there not only to see about
the permit but to see if he could get a crane to move the valve that evening. His
evidence is that there was only one person in the Control Room but if his timings
are accurate it is unlikely there would only be one person there at that particular
time. Indeed Mr Clark was in the Control Room for his changeover about 6pm
and states that it was busy at the time as was always the case between 6pm and
7pm. Mr Rankin cannot remember whom he saw in the Control Room nor if he
had dealt with that person earlier in the day. Of course if he only saw one person
it is always possible that the person he saw was not the Lead Production Operator
but the Control Room Operator. On the other hand he claims that he was told in
746
specific terms that there would be no crane available that night and it may be
unlikely that the Control Room Operator would give him such information.
Mr Rankin also says that his not very certain recollection is that the permit was
thereafter suspended. The Control Room Operator would not have done that.
Accordingly although the evidence is not entirely convincing I think there is at
least a fair possibility that Mr Rankin did return a permit to work to the Control
Room and there saw Mr Vernon or Mr Flook depending on the time of his visit.
After all because Mr Rankin had little experience of being a supervisor he was
working off a checklist in the work container and it is unlikely, even were it
necessary to remind him, that this would not clearly relate the need to return
permits to the Control Room at the end of shifts. If others were present he may
simply have forgotten about this. Mr Rankin’s conversation in the Control Room
was said just to have lasted a few minutes and he says that thereafter he left the
permit on the Control Room desk. Whichever of the two Lead Production
Operators Mr Rankin saw would have put a suspended permit among the pile of
such permits rather than retaining it as a live permit. Mr Rankin’s evidence is
that when he left the Container to visit the Control Room he had left Mr Sutton
there talking to two others. After being in the Control Room Mr Rankin returned
to the Container and Mr Sutton was still there. I mention this evidence because
otherwise it may have been a possibility that when Mr Rankin went to the
Control Room hoping to get a crane Mr Sutton had begun to loosen the blind
flanges in preparation for the refit. However in relation to this evidence Mr
McDonald raises another point about timing. He claims that he had visited the
container and been told by Sutton and Rutherford that a crane would not be
available. Apart from other considerations Mr McDonald is likely to have
747
finished his shift just before 6pm. Mr McDonald places his visit to the Score
Container at about 5pm (although he later modified this to bring his visit nearer
to 5.30pm) and he has a point of reference in relation to time in respect of his
tea-break which was about 4pm.
Mr Rankin stated that at the time when the valve came to being replaced
he and Mr Sutton would have taken off the blind flanges together.
Mr Bollands when asked about his recollection of events in the Control
Room at the changeover of shifts on 6 July stated that as from about 5.30pm the
Control Room was rather busy as would normally be the case. Mr Bollands said
that after he came on duty about 5.15pm he would acquaint himself with what
was going on and then retreat to a coffee table in the Control Room to have a cup
of coffee. This could put him out of sight of persons coming into the Control
Room. Mr Bollands also indicated that the Lead Production Operator would
normally carry out his inspection before 6pm. This would mean that if
Mr Rankin had come to the Control Room just after 6pm the normal inspection
may have finished. Of course if Mr Vernon went to perform his inspection
between say 5.45pm and 6pm it is just possible that Mr Flook had delayed to
finish his shift and would have dealt with Mr Rankin.
The defenders made the point that it was only in respect of his timings
that the pursuers challenged Mr Rankin’s evidence and this was not disputed.
Mr Rankin claimed not to remember the person he had taken the permit to
at the end of the shift but the defenders say, as they can, that he had had some
previous contact with Mr Flook whereas he may never have met Mr Vernon who
had only come on to the platform that day. Another point made by the defenders
is that when Rankin went along to the Control Room he did not know if his
748
permit would be suspended or extended. His hope was it would prove possible to
extend it and finish the work that evening. Permits were only extended at the end
of the shift so that he may not have seen any point in visiting the Control Room
before the end of the shift. Thus for example in number 15/4 of process we find
a permit to work for a PSV refurbishment that was extended by Mr Rankin on
3 July 1988. This permit was extended at 6pm until 9pm. There is another
permit in that bundle of productions which shows another extension of a permit
by Mr Rankin. This however is not a conclusive point for if on the day of the
accident he had done all he needed to do on the valve rather than waste time he
may have tried to get a crane as soon as possible so that he could get on with the
work.
Unfortunately Mr Rankin’s evidence is rather indecisive in relation to his
return of the permit to the Control Room. He does make it clear that he still had
some hope of obtaining a crane so that the work could be finished that night. It
is just possible that when he went to the Control Room, if it was a little early,
that Mr Bollands was there on his own. He indeed claims that there was only
one person in the Control Room. If he had merely seen Mr Bollands he could
not have had much success in regard to commandeering a crane. If the person
alone in the Control Room was Mr Bollands it is unlikely that he would have
given Mr Rankin the negative information about the crane that Rankin reports.
Indeed Bawdens were the agency which made cranes available. I suppose it is
possible that in the absence of a Lead Operator Mr Rankin took the permit away
until he found out what was going to happen in respect of the crane. If Bawden’s
had told him no crane was available he may have gone off to find Mr Smith to
see if anything more could have been done. Mr Smith may have been one of the
749
few Lead Operators Mr Rankin as an inexperienced supervisor knew. He
certainly seems to have sought out Mr Smith. It is plain that Mr Smith was only
interested in suspending the permit (if it was not already suspended) since he
inquired about the blind flanges. In that kind of situation Mr Rankin may have
neglected to return once more to the Control Room with the permit. The
possibility I have been discussing is extremely conjectural and is not consistent
with Mr Rankin’s recollection that he left the permit in the Control Room.
However it was clear from the content of his evidence that whatever the reality
he does not have a precise recollection of how he acted at the end of the shift in
question. His rather confused version about what took place in the Control
Room is not consistent with what might have been expected. The peculiarity of
this case is that however possible it seems that there is merit in the defenders’
contention that Mr Vernon should have known of the absence of the PSV there
are in my view strong reasons to believe that he did not have this knowledge at
least at the time there was pump failure. It follows that the precise cause of his
ignorance at the critical time must in fact be at best somewhat conjectural. The
high point of Mr Rankin’s position in relation to the suspension of his Permit
may be contained in his observation “my understanding is that we suspended the
permit”. Of course if Mr Rankin did not return the permit to the Control Room
then someone should have noticed that the live permit had not been cancelled,
extended or suspended. If this situation in fact arose it is difficult to know if
there was a deliberate departure from practice or simply an act of inadvertence.
Given the procedure that had been laid down for Mr Rankin and with
which he was at least to some degree experienced it remains eminently possible
that Mr Rankin returned the permit to work to the Control room for suspension.
750
However doubts about the matter remain. Just what happened to the suspended
permit if it was returned to the Control Room is difficult to discover.
Unfortunately Mr Rankin (no doubt because of the shock of the accident) was
unable to give any convincing account of what he had done with the permit at the
end of his shift. If the permit had been left in the Control Room then Mr Vernon
must I think be the person who at that stage dealt with it. However some hours
later he was not aware of the existence of the permit and although there could be
a number of reasons for this, one might be that he had never seen the permit.
7.1.4. The Manual Isolation Valve
It was the procedure that if a Condensate Injection Pump was closed
down the Manual Isolation Valve on the relief line was closed as an additional
isolating factor. Once closed they would normally be locked and chained (in this
connection it is perhaps worth noting that there was no evidence as to who kept
the key or as to how long it would have taken to procure this if the valve had to
be re-opened). As I have already observed this valve was approximately at the
same height as the PSV and about 18 inches away from it. Obviously the
isolation valve, if it had been closed, would have to be opened before the pump
could be re-started. Failing this the PSV could not function and there would be
no pressure relief on the pump. There was evidence of a practice to open the
manual valve before jagging to re-pressurise the pump but it was not clear that
everyone would have followed, or was expected to follow, this sequence in
respect of the valve. If Mr Vernon himself had opened the valve before carrying
out the alleged jagging of the pump then he would have seen that the PSV was
missing. I would accept that a person manually operating the Manual Valve
751
would be unlikely not to notice the absence of the PSV. Equally if Mr Richard
had gone to open the Manual Valve then he to would have seen that the PSV was
absent and might have been expected to tell Mr Vernon. However it should be
noted that there was no direct evidence to suggest that either Mr Vernon or
Mr Richard had in fact opened the Manual Valve at the time of any jagging.
There was no evidence of any express direction to open the valve before jagging
and there was no evidence that it would have been dangerous to keep the valve
closed until after jagging. Indeed the witness Mr Murray an experienced
Operator saw no danger in re-pressurising the pump before opening the Manual
Valve. The PSV would be set at a much higher pressure than the system pressure
which would be achieved at re-pressurisation (the system pressure would be
about 650 psi and the PSV would be set at about 1750 psi). Mr Seddon the
Operations Superintendent agreed with this. It is only when the pump starts
running that pressure could be built up. Because of the circumstances there
would have been little time between the tripping of the pump and the alleged
jagging. During this time Mr Vernon was also engaged in trying to restart
Pump B. The precise order of procedures may have depended on the number of
persons available for the re-pressurising process. As it happens if Mr Vernon
jagged the pump Mr Richard had already been called away before the vital
second jagging procedure. Mr Henderson had said that normally three men were
required for a re-pressurising operation and his reference to the practice of
opening manual valves possibly related only to an operation with that number of
men. Mr Murray said that he would only send someone to open the Manual
Valve at an early stage of re-pressurising the pump if he had the men available.
Moreover we were not told very clearly how an operator was expected to gain
752
access to the Manual Valve which was about 20 feet above the deck as was the
PSV. Perhaps the PSV scaffolding could have been used as an access but this is
by no means clear. Possibly a ladder or some other equipment would have to
have been arranged. In any event if other factors point to Mr Vernon not
knowing or remembering about the PSV I do not think the requirements relating
to the Manual Valve can be taken as excluding the other grounds of inference.
The witness Mr Henderson spoke to the fact that there was a practice
whereby in re-pressurising the pumps the Manual Valves would be opened as a
first step. The defenders objected to any attempt to lead evidence from
Mr Murray and Mr Seddon that there was no such practice on the grounds that
Mr Henderson had not been challenged on the point. In the interests of fairness I
sustained this objection when first made with the result that the pursuers would
have been precluded from leading any evidence to the effect that there was any
other established practice. Other objections in a similar vein were reserved.
There was some discussion as to whether my ruling related to the sequence of de-
pressurisation or re-pressurisation or indeed to sequence at all. The pursuers
argued that in fact the objections covered the circumstances in which the Manual
Isolation Valve would be used rather than precise sequence. However even if the
objections can be taken as relating to the sequence of re-pressurisation as I have
indicated there was no evidence as to the source or scope of the practice. It may
be that the sequence of events spoken to was generally more convenient. As I
have said no reason was advanced as to why individual operators could not have
deviated from the practice if it were more convenient to do so.
It should be noted that Mr Henderson, a reasonably impressive witness,
opined that in the kind of situation where one pump had tripped and there was an
753
emergency attempt to de-isolate a second pump the Lead Production Operator
(whom he supposes has two other men available) would be “getting that pump
pressured up to run whenever we had electrical power available”. This of course
is what the pursuers claim that Mr Vernon was doing.
Mr Murray informed us that the Manual Valve is operated by a straight
bar handle so that once access was gained the actual opening should take no time
at all. However Mr Murray could not say anything very useful about the Manual
Isolation Valve since he had never operated it. A fact confirmed by Mr Murray
was that Mr Vernon would have about one hour before the Suction Vessel would
be liable to overflow if the flow of condensate were not stopped. He also said
that the situation confronting Mr Vernon and his response to it was similar to
what had happened on a previous occasion. However I do not think in this
observation he was including an absent PSV.
Mr Seddon, an Operations Superintendent on Piper Alpha, had
considerable hands-on experience of the Production process. He had in particular
considerable experience of operating Manual Isolation Valves. In fact from his
evidence it appears that the de-pressurisation and re-pressurisation of equipment
such as pumps is a very common procedure indeed. He said that invariably if a
pump trips it is a “very, very minor fault”. An important observation of
Mr Seddon is that if he had required to start a pump which had been with
maintenance he would ascertain the status of the pump from the Lead
Maintenance Technician. He does not suggest for example that he would look
through the permits to work. One point he makes is that before starting the work
the permit for the maintenance work should be cancelled for it had not been
completed. However in relation to the Manual Valve the point he makes is that
754
there is a considerable difference between jagging with the Manual Valve still
closed (the pressure in these circumstances being comfortably within the
tolerance of the system) and with the pump running where pressure surges
beyond the capacity of the Manual valve might be expected.
The Defenders contended that Mr Vernon might well not have arranged
to open the Manual valve which of course would be consistent with a position
where he had realised that there would be no point in opening the manual valve
with the PSV missing. On the other hand if Mr Vernon had discovered through
an attempt to open the Manual Valve that PSV 504 was missing (assuming that
he had for some reason forgotten this) the knowledge may explain why when Mr
Grieve came on the scene he saw that Mr Vernon had apparently switched his
attention to Pump B. But as other evidence shows the main effort could always
be expected to be to try to re-start the pump which had tripped.
7.1.4. Handover from Flook to Vernon
The defenders are undoubtedly correct to claim that it was the incoming
Lead Production Operator’s responsibility to familiarise himself with the state of
the plant and of anything in the preceding shift that could affect the safety of the
ongoing production process. Thus Mr Vernon should have had a comprehensive
handover from Mr Flook and should have also had an opportunity to discuss the
state of the platform with the Operations Superintendent. Since neither of the
parties who would have been involved in the latter process have survived it is
speculative to consider what, if anything passed between Mr Vernon and
Mr Curtis. In relation to PSV 504 Mr Curtis may not even have been aware of
the up-to-date situation. Thus I doubt if it is fruitful to bring Mr Curtis into the
755
matter. In any event if Mr Vernon was likely to hear about the PSV from
anybody one might expect that it would be from Mr Flook. Mr Keen contended
that it was the duty of the incoming Lead Production Operator to familiarise
himself with permits that had been suspended during the shift and in a general
sense this too must be correct. Moreover the defenders pointed out that Vernon
had not only come onto a fresh shift but was actually commencing a new tour of
duty so that it would have been particularly necessary that he should thoroughly
familiarise himself with the state of the operations he was responsible for. It was
also to be his first encounter with the switch to Phase 1 and this may have
dominated his thoughts. It was said that the late Mr Flook was a conscientious
and meticulous workman and I do not doubt that this is true but all the victims
including Mr Vernon were given first class “references” from their surviving
colleagues and one could hardly expect anything else. Because of the nature of
the situation I should not like to make any vital decision on the basis of any such
evidence alone. Moreover I can accept that the likelihood is that Mr Flook knew
that the PSV work had been going on and at the point he came off shift he may
have had no reason to believe that the work had not been completed. To find out
about this he may have been awaiting the return to the Control Room of the PSV
permit. In any event this may not have worried him if he thought that the pump
was going to be immobilised for a number of days. The pursuers in their
pleadings “believe and aver” that Mr Flook knew that the PSV had been
removed. However knowing about the valve does no necessarily mean the
information was thought to be important. Moreover if Mr Flook had been
keeping his log with reasonable accuracy the fact that the PSV had been worked
on that day should have appeared in his log. Thus Mr Flook is likely to have
756
given Mr Vernon material from which at least it was possible to derive the
information that the PSV had been worked on that day. Whether or not Mr
Flook specifically discussed the valve work with Mr Vernon is a matter of
conjecture. As I have already indicated Mr Flook may well have thought that the
work on the valve would not be of great interest to Mr Vernon since it was
expected that work on the motor would commence that night and the possibility
of the pump being recalled may well have seemed rather remote given its
condition. Since there was a live permit for the PSV work Mr Flook may have
considered that given that he personally may not have been sure if the work had
been completed Mr Vernon would find out about the pump more informatively
when the permit was presented to Mr Vernon for extension or whatever.
However the pursuers accept that Mr Flook could be expected to have given Mr
Vernon some information to the effect that work on the PSV had been
proceeding that day. Mr Grant undoubtedly knew about the PSV work since he
had participated in it and the defenders founded on the fact that he would have
recorded such work in his own log. There was uncontested evidence that he
would have done so and it may have been surprising had he not. The pursuers
asked for a specific finding in fact that in accordance with normal and proper
practice Mr Flook would have handed over to Mr Vernon information that PSV
504 had been worked on that day. The defenders further argued that the removal
of the PSV was not simply a matter of a calibration exercise that might have been
of little interest to the Lead Production Operator but represented the removal of a
major piece of equipment that would have become very significant should the
need arise to bring the pump precipitately into commission which was in fact
what happened. Indeed the objective of the permit to work system was to make
757
sure that the Lead Production Operator was aware of everything going on at the
plant which might affect production. There seems little doubt that if a PSV was
removed during a shift and was likely still to be absent at the end of the shift the
outgoing Lead Operator would normally tell the incoming Operator or hand him
a log containing the information. On the other had as I have said the outgoing
Lead Operator might form the view that the up-to-date status of the valve would
inevitably be conveyed to the incoming Lead Operator when the Permit was
returned to him at the end of the shift (assuming as he would that the permit
would be returned). There was certainly uncontradicted evidence that the work
on PSV 504 would, if proper practice had been followed, be recorded in the
outgoing Lead Production Operator’s log. The defenders also wanted a finding
that the removal of the PSV would be recorded in the Phase 1 Operator’s log
which would be handed over to the incoming Phase 1 Operator, in this case Mr
Richard. Mr Grant had certainly spent time assisting in the removal of the valve
so that some reference to this might have been expected although just what
would be said is more conjectural. Defenders’ counsel pointed out that the relief
pipe beyond the Manual Relief valve was still connected to the Condensate
Suction Vessel which remained a significant part of the ongoing production
process so that it was important for a Lead Production Operator to be aware if he
could safely open the Manual Valve. It was said that one would have expected
Mr Vernon to take particular care to ascertain the state of the plant because he
was beginning a new tour of duty. Of course this could be a double edged point
since to begin a new tour of duty could mean that there was more than normal to
remain mindful of. The defenders argued that the visit by Mr Vernon or Mr
Richard to unload and recycle the Reciprocating Compressor Pumps would have
758
taken them to Module C and the scaffolding would have been noticed. I do not
think that there is much doubt that these pumps had been unloaded and recycled.
Mr Vernon said so to Mr Bollands when he last returned to the Control Room
and the matter is consistent with Captain Clegg who noticed a sudden increase in
flaring minutes before the accident.
There was of course evidence that because the Pressure Control Valves
PCV 1000 A and B did not always set effectively it was practice to adjust the
larger valve B if recycling. This valve had a tendency to “hunt” which meant
that the valve struggled to find its proper setting. The valves allowed the gas
released by the unloading to pass through them to flare. The object was to drop
the set point of the valve. Such resetting would have taken the person doing it
quite close to the absent PSV and on the same gangway. The problem is that
although it was obviously quite normal to adjust PCV 1000 B this was only
superficially explored. For example it was not discussed in the evidence whether
this was a critical requirement or merely a preferred practice. Mr Bollands
seemed to suggest that it was a convenience rather than a necessity. The question
of course is whether the PCVs would normally be readjusted if the recycling and
unloading had to be accomplished in circumstances of some urgency. In addition
it is not at all clear how much of the operator’s attention the valve adjustment
might have been expected to take. It is not even clear that it was necessary to go
to the valve itself to effect any necessary adjustment. Moreover the valve which
had to be reset was located much lower than PSV 504. The evidence raised the
possibility that in Phase 1 the valve was not operated at all in which case it would
not require adjustment. I do not think too much help can be extracted from the
demands of the valves in question. For the recycling operation itself 14 switches
759
had to be thrown. For Phase 2 operation it would be necessary to go to both the
PCVs and reset them but with Phase1 because some gas is already passing
through PCV 1,000 A it would only be necessary to reset B. It should also be
noted that Mr Henderson was somewhat tentative in suggesting that in Phase 1
PCV 1000 A could cope with the normal escape to flare alone. He personally
had no direct experience of resetting these valves during Phase 1. It is
accordingly also not clear that Mr Vernon or Mr Richard would have had
experience of what, if anything, was required of these valves during Phase 1 and
the same could be said of Mr Bollands.
The defenders strongly maintain that Mr Clark did not know of the valve
maintenance work. However Mr Smith had to a degree been involved in the
original instructions to the valve technicians to commence the PSV work and in
accordance with the normal procedures spoken to by witnesses the valve work
was an incident of the day’s work that Mr Smith might have been expected to
record in his log. Indeed Mr Rankin thought that Mr Smith was the person to
whom he had to report. If the material was in the log then this should have been
handed over to Mr Clark at handover. Thus either Mr Smith’s log was not
entirely complete, or Mr Clark had not registered all the material in it or had
forgotten it. The only significance of this is that it cannot be assumed that the
procedural system will always work effectively in every instance.
There was a point made by the defenders that I have to weigh in my mind
in deciding this aspect and indeed all aspects of the case. That is that if the
pursuers’ case at any point depends on hypothesis and I make one finding in fact
that is inconsistent with that hypothesis then the hypothesis fails. In general as a
matter of logic as well as law that must be true. However although the rule
760
would normally be applicable in a circumstantial case it is difficult to apply in
the abstract. A factual finding which would otherwise be attractive may be
displaced as an available possibility because the other evidence in support of a
particular hypothesis is so strong that it can only be supposed that the otherwise
contradictory fact cannot be justified.
7.1.5. Conclusions on Mr Vernon’s Knowledge
If the position is that the accident was caused by the fact that Mr Vernon
was attempting to put Pump A into Production then the defenders would have a
good defence to claims under the Indemnities if they could show that he was
acting deliberately in the knowledge that at the time PSV 504 was not in place.
There are difficult questions as to what he may have known at certain stages of
his shift but I think since it is his state of mind at the time he would have been
jagging the pump that is critical, it assists to begin at that point. The question of
onus of proof could arise but since I see a reasonable way through the difficult
tangle that surrounds this matter I do not require to found my determination on
onus. Thus onus is a matter I need not at this point decide although my initial
impression is that the onus rests on the defenders to prove wilful misconduct.
The alternative would be that the pursuers had to prove a negative.
My starting point must be that it would have been surprising if Mr
Vernon had been prepared to ignore safety procedures to the extent that he was
prepared to run the pump without a relief system to cope with any build up of
pressure. Claims by his former workmates that he was exceptionally
conscientious must of course be viewed cautiously but there is certainly no
indication in the evidence that he might be capable of downright irresponsibility.
761
It is clear from the evidence that all the Lead Production Operators and the
ordinary Operators were well aware that it was bad practice to run a pump
without a PSV in place. Indeed there was no suggestion from the considerable
number of qualified workmen who gave evidence that such a thing has ever been
done previously. There is of course always a first time but one would have to
ask why Mr Vernon would have taken a risk. Personally he had nothing to gain.
He had indeed a lot to lose because the course he is alleged to have followed was
very exposed to discovery by his superiors and could have attracted a severe
reprimand or worse. If Mr Vernon did consider that the exigencies of the
situation he was faced with might justify a departure from reasonably safe
procedures then one would at least have expected that he would discuss the
problem with his colleagues. He said nothing either to Mr Bollands nor to Mr
Clark both of whom he could readily have consulted. Moreover supposing that
in fact Mr Clark was unaware that the PSV had been removed equally it would
not have been surprising if he had known. He might have noticed the missing
PSV while walking around the platform or Mr Smith might have told him at the
handover. Thus Mr Vernon would not have known what Mr Clark would have
known about the PSVs and yet allegedly he blithely ignored both Mr Clark and
Mr Bollands on the matter. Furthermore Mr Richard would have found out that
the PSV was missing when he went to release the Manual Valve if he did not
know already. The prospect of losing Production was serious but would
probably have been confined to the loss of condensate production since
condensate would have had to be released to flare if the pumps had continued to
remain disabled. However if Mr Vernon was concerned that he would lose
production it is remarkable that he did not consult the various superiors in the
762
management line who were on the platform. Mr Lynch indicated that it was
acceptable, if necessary, to wake them out of their beds if there were a
breakdown. This would have relieved Mr Vernon of the responsibility were
indeed anyone likely to take a decision to run the pump without the PSV. Of
course it is unlikely that any of his superiors in management would have
authorised the use of Pump A so that there was little risk of his being criticised
for not putting that pump into production. There were many routes by which
senior management could have found out about Mr Vernon’s irregularity.
Moreover there is a further consideration. The defenders’ contention is that
Mr Vernon would have known that the valve maintenance was incomplete and
suspended. If Mr Vernon had restarted the pump A in these circumstances then
there was always the prospect that next shift the valve fitters would seek to
resume what they were doing. This would mean removing the blind flange with
condensate running through the system. Of course if the permit to work system
had worked properly the valve permit would not have been renewed but there
was clearly an undesirable risk of a mistake or misunderstanding which simply
highlights the risk of running the pump with the PSV missing.
The defenders contend that although it was bad practice to run the pump
without a PCV it may not have seemed such a great risk to Mr Vernon. The
valve is only needed if the pressure builds up and there are additional safety
devices including safety trip devices that could have relieved the flow pressure if
the pressure began to build up excessively. However the immediate risk of
pressurising the pump was not only that when the pump was in use the pressure
valve would not be there as a relief. The relief line had been opened up and was
only protected by a blind flange. This may have sufficed if the flange had been
763
pressure tested. This was the procedure with flanges in use on an active line.
There was no suggestion that Mr Vernon had made any arrangement to have the
flange pressure tested and indeed we are not even certain how quickly this could
have been done if desired. Of course if the line had been pressure tested any
deficiency in the fitting of the flange would have been discovered. As soon as
the pump begins to be pressurised one is dependent on an untested flange to
contain the condensate.
One question is the origin of the red de-isolation tags which indisputably
Mr Vernon released to Mr Clark to sign off. As between Mr Bollands and
Mr Clark I formed the view that Mr Bollands had in general been the more
accurate observer but it would be remarkable if any witness could be taken as
totally reliable in all matters of detail and this must include Mr Bollands.
Certainly a point was made that if Mr Clark knew that the PSVs were missing he
would have had a lot to answer for because he released the electrical isolations. I
have little doubt that he would have known that it was bad procedure to run the
pumps without PSVs. It was also argued that Mr Bollands would have had an
interest to cover his tracks by denying all knowledge of the PSV maintenance but
this is less obviously so since in the presence of Mr Vernon and Mr Clark he
could have had little direct responsibility. However although Mr Clark’s
evidence has to be read with a certain caution and is not in all respects
convincing I am by no means in a position to suggest that he was consciously
misleading the Court. Both Mr Clark and Mr Bollands suffered frightening
experiences when the accident occurred. Mr Clark got blown across the Control
Room and was injured. With such a shock it would perhaps be expecting too
764
much for Mr Clark in particular to have a reliable recollection of detail some
years after the accident.
According to Mr Bollands a permit for the planned maintenance work had
been issued and it was this pink permit that Mr Vernon took out of the live
permit slot to present to Mr Clark for signature. Mr Clark on the other hand
states that the permit application and tags were in the Safety Office and the
permit had never been completed and issued. I doubt if either witness is entirely
accurate. Since the maintenance permit was Mr Clark’s responsibility it would
indeed be surprising if he did not know about its issue. The matter would have
inevitably been mentioned to him at handover and one would expect that he
would have been responsible for having it extended if it were to be a permit in
the live permit container. Moreover it would not have been extended unless
work was proceeding during the evening shift and it would be surprising if Mr
Clark did not know about this since he would have been responsible for it. Mr
Clark at least purports to remember that Mr Smith had told him specifically that
the Permit had not been issued and this account of what he had been told may
well be true. However, whatever Mr Smith said about the whereabouts of the
permit application, I doubt if this was in the Safety Office even if the permit was
at the stage of only being an application. There are parts of Mr Bollands’
evidence where it is possible his memory is not accurate. However there are
certain details which are more likely to be accurate than others. As Control
Room Operator Mr Bollands would have required to know the work proceeding
during his shift. Thus he may well not have looked at the suspended permits
which would have included the one relating to PSV 504. On the other hand he
remembers looking at a permit which certainly gave him the impression that the
765
Pump was undergoing planned maintenance and this he remembers was a pink
permit (as it would be). I think when he came on duty he must have looked at
something which related to planned maintenance. He claims that this was a live
permit but if he is wrong about the live permit coming out of the live permit
container the reality may be that what he saw was the permit application. I think
that despite Mr Clark’s account of what he had been told the permit application
(if there were such) was left lying in the Control Room ready for Mr Clark’s
immediate attention when he came to proceed with the Voith Coupling work
which he hoped to perform during the nightshift. There was evidence that
sometimes after the necessary isolations had been carried out a permit was left
lying in the Control Room for issue. The situation may be quite different when it
is not known precisely when work will proceed but this was work where urgent
completion was desired particularly after isolations had been completed. It is
possible that Mr Clark had retrieved the permit himself from the Safety Office.
He was challenged as to whether or not he had been in the Safety Office after
coming on duty and his evidence was rather vague on this. However it got to the
Control Room I think it was there when Mr Bollands looked through what he
conceived to be permits relevant to his duties and also when Mr Vernon looked
for the maintenance electrical tags. It is of course suggested that what Mr
Vernon must have done was to take his tags from the PSV permit but I think this
unlikely for reasons I shall expand upon shortly. If the permit had not in fact
been issued then I would conclude that the permit form with its tags was
available at the relevant time in the Control Room. It is strange that Mr Bollands
had the impression that instrument work had been carried on at the pump but
since no other evidence supports this I cannot exclude the possibility that this is
766
simply some quirk of his memory. That I think must be so since it would be an
odd tale to make up.
One circumstance that Mr Clark accepts without hesitation is that the
original electrical isolations had been effected for the planned maintenance
proposal and had been completed. This would make sense for once the pump
had been isolated by de-pressurisation one would not want someone accidentally
switching on the pump. The defenders suggested that what Mr Clark was saying
is that the permits had been prepared ready for signing but the isolations had not
taken place. However this does not at all accord with Mr Clark’s evidence. He
claims not to have known about the PSV work or he would not have signed off
the tags. Indeed when he signed the red tags he would not according to his
evidence have known that they could possibly relate to valve work (since he
claims not to have known about this) and must have had grounds for believing
that the maintenance isolations had been completed. Otherwise what tags did he
think that he was signing. The defenders’ Counsel attempted to draw some
particular conclusions from general evidence that the electrical isolations would
not be effected until the work was about to start. However in relation to the
Maintenance programme all the evidence was to the effect that the electrical
isolations necessary for this programme had been completed. The work was not
simply a single job but was expected to be extensive and it was anticipated that
some might begin during the night shift. In particular it was expected that the
Voith Coupling work would be carried out during the night shift and although
this on its own may not have required a hot work permit the work was to be
carried out under the maintenance programme permit which would have required
electrical isolation. Mr Clark was an experienced Maintenance Lead Hand. He
767
claimed that the Maintenance permit had not been issued. Nevertheless he signed
off tags which he assumed related to the maintenance permit. This I think shows
that any practice of electrically isolating within a very short time of the work
beginning was not in all circumstances followed particularly perhaps if it was
part of a more substantial isolation process. The position was therefore that
under the maintenance application the electrical switches would have been
immobilised and sections of the tags attached thereto so that the power could not
be restored unless the electricians were presented with discharged isolation tags.
This is very important since it means that the electricity could not be restored
unless the tags attached to the maintenance permit or application had been signed
off by Mr Vernon and Mr Clark. Mr Clark accepts this and goes beyond it for as
he claims he would not have signed off tags (which he assumed were
Maintenance permit tags relating to the pump) if he had known that PSV tags
were in force. Mr Clark would have had no obvious authority to sign off any
valve tags since the performing authority for that work was Mr Rankin. There
was a preponderance of evidence to the fact that a PSV Maintenance permit
would be a blue cold permit and many (though not all of the relevant authorities)
would require electrical isolations. The witness Mr Lloyd thought that the
normal practice was to have electrical isolations for PSV calibrations. The
Safety Procedure Rules specifically provide that each permit will have the tags
relevant to it attached to it. This alone makes sense and there was no evidence
that the operators ever departed from their prescribed safety rules. For example
if only one set of tags were provided for two distinct jobs requiring isolation at
the same time then if these were attached to one permit the risk would exist that
when work relating to one permit was completed and the permit cancelled the
768
electricity would be restored while the other work is proceeding. This approach
can be illustrated in relation to the Planned Maintenance Permit. Although the
various items of work were likely to be proceeding at the same time separate tags
were required for the pump motor and the lube oil motor. Thus Mr Clark
obviously knew what he was talking about when he said that if he had known
that a PSV permit with electrical tags were out, there would have been no point
in signing off tags for the Planned Maintenance Permit. The same would apply if
the PSV permits alone were signed off. The point is that there would be attached
to the switch lock two sets of tags, the tags relating to the two pump motors
being one set and the tags relating to the PSV being the other. Then electricians
could not restore electricity unless they had authority to discharge all the tags
attached. I do not think it was suggested that Mr Vernon was proposing to
override the whole tags system. The trouble he was taking to get Mr Clark’s
signature indicates the opposite.
Everything about Mr Vernon’s communications in the Control Room
suggests that he was concentrating on the planned maintenance situation. There
is no suggestion that he visited the Safety Office at any time. Even if we suppose
that Mr Vernon must have visited the Safety Office then on the basis of the
defenders’ submissions he would only have found the maintenance tags there and
these alone would not have been effective if he knew that there were two separate
sets of isolation tags. When Mr Vernon spoke to Mr Clark on the telephone his
first enquiry was about the position of the planned maintenance. He was
apparently keen to get the pump back from that. Moreover his question to
Mr Clark was somewhat curious if the position were that the maintenance permit
had not been issued. He first asked what the status of the pump was and if work
769
had been done on it. This would be an odd approach for a Lead Production
Operator if there was no permit issued for he would know that no work at all
could proceed without a permit being issued. Thus either there was a live permit
or he had forgotten that the permit had not actually been issued. He did not say
to Mr Clark that there was a PSV permit outstanding and that he would like these
isolations signed-off (assuming indeed that the PSV permit had provided for such
isolation). This is what one would have expected if he knew there was no
planned maintenance permit and was standing with the PSV tags in his hand.
Instead the whole thrust of his short conversation with Mr Clark seemed to be
directed at planned maintenance. He seems certainly to have known about the
proposed planned maintenance. He would not have asked if work had been done
if he had not known about the isolations and this is what one would expect since
that must have been an important element in Mr Flook’s handover. The various
steps to isolate the pump must have figured prominently in Mr Flook’s log.
However if Mr Vernon had it in his mind that the PSV permit was alive (with its
isolations in force) he must have realised, just as Mr Clark did, that there was no
way the electricity could be restored without releasing both sets of electrical
isolations.
The defenders placed great store in the effectiveness of the procedures in
insuring that the Lead Production Operator was at all times well aware of the
state of the production situation. However at best for the defenders Mr Vernon
must have inadvertently forgotten at least one important fact. Either it had
escaped his mind that there were planned maintenance isolations or it had slipped
his mind that there was a PSV permit. He could hardly have supposed that he
could electrically de-isolate both permits unless he had access to all the tags.
770
Moreover as I have said when he spoke to Mr Clark the emphasis in his
conversation was on Maintenance and one would have supposed that the
conversation about the red tags related to that. This clearly is what Mr Clark
thought. There was certainly no evidence that Mr Vernon got hold of all the
tags. If he had wanted the PSV tags (assuming there were some) he would have
required to retrieve the permit from the suspended permits relating to the 84-foot
level. Of course this would not have bothered him if he was not at the time
aware that a PSV permit and possibly tags relating to it were in existence. If Mr
Clark is right and the maintenance permit application was in the Safety Office he
would also have required to visit there to get hold of the Maintenance Tags. Mr
Clark would have been presented with more tags than he speaks to. Mr Bollands
remembers Mr Vernon having in his hand a permit with tags attached. This
seemed a vivid enough recollection to be substantially true. He may be mistaken
in thinking that this was a live permit or even that it came from the 68-foot
permit container and not simply from the desk nearby but his belief that it was a
maintenance permit could only have arisen from it being red (or pink as the
colour is sometimes described) and everything points to Mr Vernon being
interested in discharging the planned Maintenance and not the PSVs alone as
would be the alternative hypothesis. If it is clear that at the relevant time the
PSV permit must have slipped Mr Vernon’s mind (assuming that is that he had
ever been aware of it) it may not matter what he had known at the earlier stage of
the evening. The defenders of course approached the problem from the opposite
end and contended (at considerable length) that he must have known in the early
evening and possibly later but in any event it must therefore be assumed that he
knew when allegedly he went to restart the pump. One problem of course is that
771
at least in one respect the pursuers seem to accept that Mr Vernon suspended the
permit. This was originally denied by the defenders and as I have discussed the
averment is based on material which is contradicted by the evidence that has been
allowed to emerge. However the matter is not critical. First of all if the
averments govern the position this means that the pursuers are accepting that
there had been a live PSV permit. I do not think that there can be much doubt
about this. Mr Rankin may have had his problems as a witness but he was
undoubtedly sufficiently experienced to know that he could not calibrate Valves
without a permit. If at one stage he may have been confused about this because
of the intervention of the planned maintenance isolations he took the trouble to
ask about the position and was put right. There was considerable evidence about
the timing of his progress but on balance as I have said I prefer the view that he
did not finish all he was able to do on the day of the accident until about 6pm and
then he took his permit to the Control Room at least for some purpose. If as the
defenders contend the pursuers are bound to a position that the permit was
properly suspended Mr Vernon was in all probability the person who suspended
the permit and this is what the pursuers aver. As I have said the pursuers’
averments on this element of their case seem to me to involve a massive non
sequitur. If the pursuers’ averments are to be taken literally the only occasion
when the Lead Production Operator could under the alleged safety rules possibly
have a duty to inspect a site relating to an uncompleted job would be when a
permit is suspended. However this would involve the Lead Operator knowing
about the state of the work in the first place for the application to suspend the
permit would tell him that. It is therefore difficult to see what the inspection
would add to his knowledge. Moreover certainly as far as an operator was
772
concerned he would on the evidence not necessarily be aware that it was a
prudent procedure to inspect a site if he could properly be satisfied that the work
had been left in safe condition. As I have said in reality there appears to be a
doubt as to whether in the early evening of the accident Mr Vernon had the
opportunity to discover from a permit to work that the valve was out of position.
However it is not necessary for me to rely on my view of the technical arguments
relating to the pursuers’ own pleadings. I shall assume that as the pursuers
seemed to assert at least at one point of the case that Mr Vernon did suspend the
permit. However he derived any information in the permit against a background
when he had just begun his tour and may have had many different situations to
worry about. We know for example that the process had just switched over to
Phase 1 from Phase 2. This was a considerable change in the process and
Mr Vernon was about to experience it for the first time at least for some years.
He may therefore have paid limited attention to a valve that was missing from a
Pump that was in any event to be unavailable for some time. It also seems that
the permit if presented to him for suspension was probably presented rather later
than normal - perhaps just after six o’clock. When Mr Flook made his handover
he may not have realised that the valve work would spill over until the next day.
In any event if that were to happen Mr Vernon would be able to ask for the
details and he may have thought that little needed to be said about the PSV
particularly with the pump in planned maintenance. The same points can be
made in relation to Mr Grant’s handover to Mr Richard. Mr Grant may not have
appreciated that the PSV job had not finished particularly as there was no
indication that Mr Rankin would report to him nor did he have any responsibility.
If Mr Grant was concentrating on matters that the incoming Operator would have
773
to involve himself with then there may have seemed little point in making
reference to the missing PSV. Indeed Mr Grieve in his evidence said that the
Phase I operator would go through with the incoming operator anything which
started during the shift which would relate to the work of the operators. This of
course would not include work handed into the control of maintenance. Indeed
Mr Grieve indicated that the entry in the log would simply record that the
machine had been handed over to maintenance. Mr Bollands took a rather
different view of what would have been recorded in the log but even if he was
right the evidence would simply be recording that the detailed implementation of
the practice could vary from operator to operator. In any event we do not know
just how studiously Mr Richard required to look at the log if he had an
apparently full oral handover. I am not convinced that the manual valve had
been opened before any jagging took place and with the switchover to Phase 1
the proper procedure for resetting of the relief valves to flare may have been
ignored by say Mr Richard who may not have been familiar with how to cope
with that situation. This would also be likely if Mr Vernon was working under
pressurised conditions with inadequate manpower.
It was suggested that Mr Vernon may have learned about the missing
PSVs after leaving the Control Room - say from attempting to open the Manual
Valve or from Mr Richard. The suggestion goes wider than the question of
knowledge for it is that he may have decided not to proceed with the re-
introduction of Pump A. If that had been the position I should have expected
him to radio Mr Clark to cancel the electricians. Mr Vernon would hardly have
wanted to de-isolate the pump and then proceed to isolate it again for completion
of the valve work. Regarding inspection of the pump it may well be the case that
774
Mr Vernon had completed his normal walkabout before Mr Rankin reported to
him that he required the pump suspended. We were not really told what his
practice would have been if subsequent inspections were required. This may
have depended on the other tasks at hand and the importance of urgency in the
inspection. Thus the inspection of a valve site and the nameplate work carried
out by Mr MacGregor were hardly likely to cause much danger and may have
justified low priority. When Mr Smith heard that the valve work had not been
fitted his only concern was that blind flanges had been fitted. In general there
was a limit to what a walkabout could reveal. Mr Clark said that he would not
have noticed scaffolding. There was a great deal of it about and much was
concerned with matters such as painting and other projects that do not involve
production. Mr Clark also revealed that PSV 504 is situated in an area where
there is a mass of complex piping. There are about 800 valves on the platform
and he could not even identify PSV 504 without reference to a drawing. It is
perhaps interesting that none of the operators giving evidence who might have
been expected to know that PSV 504 was missing seem to have known so.
Mr Bollands, Mr Clark, and Mr Grieve claim not to have known. It is unlikely
that Mr White, the Maintenance Superintendent knew since he was present when
Mr Clark agreed to return the pump to the operating department. If Mr Vernon
hoped to restart the pump in the knowledge that the PSV was missing he might
have expected some resistance from Mr Richard if he had known but there was
no evidence to suggest this. The problem might well have been that no-one was
focusing on the pump because it was presumed to be out of commission for
maintenance. Mr Vernon for his part, if he had recollected the absence of the
PSV valve could not have known that all these persons did not know the position
775
but there is no suggestion that he attempted to conspire with them to breach
safety practices.
The situation on the platform could admit of many circumstances which
might explain how Mr Vernon came to forget about the PSV or not to know that
it was not in position. The problem for the defenders is that there is in my view
fairly clear eyewitness evidence from which it can be inferred that in the final
period before the accident Mr Vernon was not aware that the PSV was absent.
On the other hand the evidence of what might have taken place to produce that
situation is vague and leads to no convincing conclusion. Many of the
possibilities remain totally speculative and we shall never know what happened
at and following on the handover. Among the various possibilities the likeliest is
that at some stage in the evening Mr Vernon had suspended or at least seen the
PSV permit but that either in the whole circumstances surrounding the planned
work on the pump it had failed to register in his mind that the state of the valve
had any significance or if it did so register it had slipped his mind later.
In arriving at a view of Mr Vernon’s behaviour I am in no way suggesting
that he was not seriously negligent in allowing the PSV permit to escape his
mind, or in any event as the Lead Production Operator on duty not having
discovered that it was absent.
7.2. Mr Sutton and the Blind Flange
7.2.1. His Involvement
There was no dispute that in terms of OPCAL’s contract with Score the
latter was required to fit blind flanges to all open ended pipework. The fitting of
776
blind flanges was also a condition of the PSV permit to work. Nor was it
disputed that such blind flanges ought to have been secured tightly by use of a
flogging hammer or by combination spanners. In the case of a PSV being
removed the purpose of the blind flange was not only to prevent dirt or other
impurities entering the pump but also to prevent any hydrocarbon remaining in
the pipe from escaping. These purposes are fairly obvious and should be known
to any reasonably experienced valve fitter.
The tests carried out by Mr Stanton showed that if the flange is finger
tightened alone it would not withstand the pressure which would be introduced to
the valve upon re-pressurisation of the pump. On the other hand if it is tightened
by flogging or by use of combination spanners then it should be able to withstand
that pressure. A lesser degree of tightening would permit a leak to develop.
It was accepted by the pursuers that their allegation that Mr Sutton had
caused the leak by not flogging or using combination spanners on the blind
flange depended entirely on inference. No-one observed him when he was
actually putting the bolts on the relevant flange. Moreover most unfortunately
Mr Sutton did not survive the accident so that we do not have his own testimony.
It is I think obvious that given that a properly fitted flange should not leak
then if the flange did leak the probability must be that the flange was not fitted
properly. The defenders’ case is that there was no reason why Mr Sutton should
not have followed his normal practice and tightened the flange adequately. The
pursuers say that there are three reasons why Mr Sutton may not have fitted the
flange properly. One is that he expected that the PSV would be replaced that
evening and therefore did not expect that tightening the flange would be
important. Another possibility that the pursuers advance is that he was working
777
in a restricted space and therefore found it difficult to use tools. The third
possibility is that Mr Sutton or Mr Rankin had selected the wrong size of flange
for the pipe (a 1500 standard flange for a 900 pipe). It was conceded that this
alone would not cause a leak but it was suggested that Mr Sutton had found that
he had the wrong size of flange then thinking that the valve would be replaced
that day he may not have bothered to tighten the flange properly. In other words
it is suggested that the problem with size may have deflected him from tightening
the flange as carefully as he might otherwise have done.
The pursuers averred quite plainly that Mr Sutton failed to secure the
blind flange securely. The defenders submitted that these were not derivative or
inferential averments and that the pursuers had therefore obliged themselves to
prove by direct evidence that Mr Sutton had not secured the flange properly.
They are correct in stating that there is no direct evidence that Mr Sutton failed to
tighten the flange fully. They argue that if the pursuers sought to rely on an
inferential case they should have introduced their averment with words such as
“believed and averred” to show that their case was based on inference. They
should also have set out clearly the circumstances which might permit them to
draw any inference they proposed to found on. The only foundation which the
pursuers plead in support of their general averment is that the flange leaked so
that it must have lacked proper tightening. I think at this stage of the case where
the whole factual background has been extensively explored it is a narrow
technical point to complain about the pleadings in the manner I have indicated.
If the evidence now before me allows for an inference that the blind flange was
not properly secured by Mr Sutton I see no pleading difficulty about a finding in
these terms. The defenders further argue that the pursuers can only establish
778
their case of incorrect tightening of the flange if the Court first makes a finding
that the flange leaked. This point I think has merit. There is no other material
from which it could be inferred that the flange was not fixed properly. However
it was contended there was no direct evidence that condensate leaked from the
flange. Nobody actually saw this happen. I would agree with the defenders to
the extent that the position is that there is no evidence about the fitting of the
flange that would enable the pursuers to claim that such evidence in itself
supports the view that the accident was caused by leakage from the flange. The
negligence of Sutton could only arise if it is clear that the tragedy was caused by
a leak of condensate from the blind flange.
The defenders develop their argument to the effect that if Mr Sutton did
not follow the established practice for the fitting of the blind flange this must
have been a deliberate departure from normal and prudent practice. This could
of course have implications for the application of the indemnities. I think it
would be rather strained to regard a failure by Mr Sutton to tighten the bolts as
“wilful misconduct” even as defined by the Contracts. There is always the
possibility that any failure to tighten the bolts was simply inadvertence promoted
by careless application to the job. Even if he decided not to flog the bolts this
may have been due to a misunderstanding as to what was required when the blind
flange was thought only to be in place for a short time. He did know the
established practice for tightening bolts but may not have realised that it was
unsafe to depart from the practice in any circumstances whatsoever. Against the
background of the proposed maintenance of the pump it may have been beyond
Mr Sutton’s comprehension that circumstances could arise which would
necessitate the hurried re-introduction of the pump. He should not have
779
presumed that in the situation he was faced with anything less than a fully tight
flange would be safe but his error may have been due to a misunderstanding of
the dangers rather than a deliberate ignoring of them. If he was finding it too
difficult to flog the bolts or manage the heavy flange in the cramped situation in
which he found himself then he had a duty not simply to leave matters but to
seek assistance. I think this would be an extension of the case that the pursuers
have pleaded. However his conduct in such circumstances would not be
deliberate departure from practice. As Mr Sutton was tightening the bolts
someone may have arrived and distracted him so that he inadvertently forgot to
complete the tightening sequence. In the whole circumstances if Mr Sutton did
fail to bolt the flange insecurely I could not proceed to conclude that he did this
as an act of wilful misconduct. The defenders seek to extend this argument by
saying that if Mr Sutton knew that he had not fitted the flange properly he was
also guilty of wilful misconduct by not informing Mr Smith of the position when
he met him at the end of the shift. In fact it may never have occurred to him that
he was misleading his superiors in any material way. It may be possible to infer
that the bolts on the flange were not properly tightened by Mr Sutton. However
if this is what happened it is not possible to infer what led him not to do his work
properly.
The defenders again referred me to the case of McWilliams v Sir William
Arroll 1962 S.C.(H.L.) 70 where it was observed that an inference unfavourable
to a deceased should not be drawn except upon a strong balance of probabilities.
This of course only creates a presumption and it must yield to the evidence
before a Court. The defenders submitted that if it is assumed initially that Mr
Sutton was a reasonable man (the appropriate assumption to begin with) then
780
unless it is positively proved that he acted unreasonably it would not be possible
to infer that anything happened due to his misconduct. However in my view if
other evidence shows that the perceived state of facts could only have arisen if
Mr Sutton had not acted unreasonably then I find no difficulty in arriving at that
conclusion even in the absence of immediate evidence pointing to the fact that he
had acted irregularly. Generally the valve calibration work was completed on the
day it began.
Understandably the defenders also submit that Mr Sutton was an
experienced valve fitter, he was familiar with the platform and there was no
evidence that he or indeed other valve fitters had ever failed to tighten flanges
properly. Of course one answer to this may be that it is perhaps unlikely that the
very peculiar circumstances which preceded the accident had ever before
occurred so that even if a blind flange had in the past not been secured properly
the chances are that this would have been noticed.
When Mr Rankin gave his evidence he accepted that the blind flanges had
to be fitted securely. He said that “There is, I think, only one way to fit a flange
and that is with the correct flange and you tighten up the studs properly.”
Mr Rankin thought that “the reason for applying these blind flanges to the open
pipework was primarily to protect the faces of the flange, to stop any accidental
spillage from the system, or to prevent any dirt from entering from outside”.
These illustrate the experience of a person who until a few weeks earlier had
been working as an ordinary valve fitter. Mr Rankin confirmed that he and
Sutton had been able to do all the other valves they had dealt with on their tour in
one shift (sometimes extended with overtime). Certainly Mr Rankin said that
PSV 504 was the last valve he and Sutton had to work on during their tour and
781
that he expected to finish the job on the day he had started it. He confirmed that
some flanges for the work were kept in the Score Container and that other
flanges could be obtained from a store at a lower level. Mr Rankin did not assist
Mr Sutton in the fitting of the blind flanges and it is clear that Mr Sutton fitted
them on his own. After the flanges were fitted by Sutton, Mr Rankin, who had
left the site did not return to the site to check Mr Sutton’s work. There was no
attempt to develop a case that Mr Rankin failed in a duty to inspect the work but
his failure to check would ensure that any failure to tighten the bolts would pass
unnoticed.
Mr McDonald the rigger who gave evidence had sometimes helped
Sutton to remove valves on other jobs. He confirmed that Sutton seemed to be a
reasonably competent workman. Mr McDonald said that he had seen Mr Sutton
tighten up flange bolts by hand but the matter was not pursued in evidence so that
it is not entirely clear if the witness meant that he had seen Sutton tighten bolts
with his fingers alone or if he meant tightened by hand with combinations
spanners. He affirmed that the blind flanges were heavy and that was obvious
from the ones produced in Court. Mr McDonald was able to tell me that
Mr Sutton’s worksite had been a very congested area. In fact he thought that
given the valves were heavy his view would be that in that constricted site it
would require two men to fit the valve properly. On the other hand the witness
Bagnall, who seemed to have wider experience of the flanges thought that one
man could fit the flange but with difficulty. He thought for example that there
might have been difficulty in keeping the mating flanges parallel. He thought
that one flange would take from half an hour to three-quarters of an hour with
one man but perhaps fifteen to twenty minutes with two men. In fact Mr Bagnall
782
would have put two men on the job. He also expressed the opinion that it could
have been difficult to use the combination spanner in the confined space that
would have been available to Mr Sutton. If two men had been available then one
on either side of the pipe could have wielded a combination spanner. Thus if
Mr Sutton had only got combination spanners available to him he may have been
faced with the problem of going off to procure a flogging hammer or persuading
Mr Rankin to return and help him. It should perhaps be noted that a combination
spanner is a spanner which has a round headed spanner at one end and an open-
ended spanner at the other end. There is no case against Score for not having
enough men on the job but in any event it was Mr Sutton’s duty not to leave the
valve in a half tightened state without reporting any difficulty to Mr Rankin.
What is significant however is that he is likely to have had some trouble in fitting
the valve properly and if he thought that the work was only for a short time he
may have had a temptation to do the tightening half-heartedly.
The evidence showed a degree of uncertainty as to the size of the valve
unit being serviced. Mr Wylie who was a Quality Assessor who certified re-
calibrated valves was shown the certificate which related to the earlier re-
calibration of PSV 505 (the valve on Pump B equivalent to PSV 504 and agreed
to be the same) and he indicated that on the certificate the valve was shown as
having a rating of 1500 lbws on the downstream side and of 600 lbws on the
upstream side. However the information on the certificate had been filled in by
the valve engineer who was Mr Bruce. There was therefore a suggestion that
possibly PSV 504 had a similar rating. However Mr Wottge’s clear view which I
have no reason to doubt was that PSV 504 was a 900 lbws rated valve although
the defenders challenged him on this point (this may be because the pursuers
783
themselves had raised in their pleadings the possibility that the wrong blind
flange size had been chosen). The pressure that the valve was planned to
withstand did not require a higher rating than 900 lbws. Moreover a drawing
which was part of OPCAL’s records and which purported to be from the
manufacturers of the pump (12/170 of process) showed that the flange for the
PSVs had a rating of 900 lbws. Other documentation relating to the valve in the
pursuers’ possession after the accident were to the effect that originally the valve
had a 900 lbws rating. One drawing (12/146) perhaps suggests that the valve
may have had a different rating but Mr Wottge did not think this was accurate
particularly in the light of the manufacturers’ own drawing. Whether or not the
certificate for PSV 505 was accurate need not concern me. Confusion could
have arisen because the valve itself was rated at 1500 lbws although the outlet
was rated 900 lbws. Mr Standen said that even if a valve had a mismatched size
of flange this would not matter provided the flange was effectively tightened.
However there was evidence from a Mr Pirie that one could not put a 900 lbws
flange on a 1500 lbws pipe because the bolts would not marry up. Mr Bagnall on
the other hand indicated that in the opposite case one could put a 1500 lbws
flange on a 900 lbws pipe. In any event it was Mr Sutton’s job to see that he was
fitting the correct size of blind flange but there was really no evidence that he did
not do so. If he was in fact trying to fit a flange which was a higher rating than
needed (which I doubt) not only had the fitters selected the wrong flange for the
job but he had made the task of fitting the flanges harder since the 1500 lbws
flange was much heavier. According to Mr Bagnall a fitter at the valve site
would have no difficulty in recognising that he had the wrong size of flange. At
784
the end of the day I did not understand the pursuers to press their case that the
wrong size of flange may have been fitted.
Number 12/230 of process was a valve calibration certificate dated
22nd June 1984 relating to PSV 504 and it shows the rating at 4 inch 900 lbws.
In the certificate 12/228 the valve size of PSV is shown as 4 inch 1500 lbws.
The date of the certificate is October 1985. A certificate of the same date
relating to PSV 505 also shows that valve with the higher rating. However Mr
Wottge confirmed that there was no change to the relevant line between 1984 and
1985. A question may arise as to whether the fitters may have been confused by
looking at earlier certificates and seeing perhaps a certificate that declared the
valve to have a 1500 rating. However if the wrong size of flange had been taken
to the site as Mr Bagnall said this should immediately become obvious to the
fitter and all that was required was to fetch the proper size. There was a store of
flanges kept on the platform. Mr Rankin did not suggest that such a problem had
arisen. In any event Mr Sutton had worked on PSV 504 not long before so that
he should have known the flanges that were fitted to these PSVs notwithstanding
that the certificate (which he would not have himself prepared) had been
inaccurate. A Mr Reid gave evidence. He was a Production Manager with the
Wood Group. In his earlier post as Quality Assessor he had completed the
certificate relating to October 1984. He explained that the outlet from the valve
was not large and he had rated it at 900 lbws. He thought he may have got the
rating from Information Cards with all the valve details on them although he
could not be sure of this. It was Mr Pirie who had carried out the calibration of
the two PSVs in 1985 and he indicated that it had been a rushed job. It was not
785
at all clear that the person who fitted the flange was the person who had filled
details on the certificates.
The witness Mr Barclay was a Maintenance Engineer who had formerly
worked as a Quality Assessor with the Wood Group. He had also filled in one of
the certificates with an incorrect rating. He said that he may have obtained his
information from a tag on the valve but this as I have already observed could
have misled him since the rating of the valve was higher than that at the outlet.
There clearly had been occasional confusion as to the correct size of the
flange that ought to have been fitted to the pipework leading to PSV 504. This
whole area of investigation however may have largely been a red herring. It was
the fitters’ job to secure a blind flange and nothing emerged to indicate that they
would have had any difficulty in doing this had they applied themselves to the
work with adequate care. If there was any problem about the size of the blind
flange this would have become clear immediately an attempt was made to fit the
flange at the site. There was no suggestion that OPCAL’s store of blind flanges
lacked the necessary range. If this had been the problem one would have
expected Mr Rankin to have mentioned it. In any event if there was any problem
with the blind flange it was that the flange itself was too big and if such a flange
is fitted tightly it should not leak. Thus one of the valve fitters doing the fitting
job properly (and Mr Sutton in particular as the person effecting the fitting)
should have been able to achieve a securely fitting blind flange. There was no
evidence that there was any defect in the ring seal and presumably if there had
been this would be noted by a competent valve fitter and the seal or flange
replaced. There was no evidence to suggest that the seal was faulty. The real
786
issue appears to be how the blind flanges which obviously were fitted were
tightened.
7.2.2. Implications in Law - Foreseeability
The defenders submitted that even were it the case that Mr Sutton had not
tightened the blind flange on the PSV effectively and that this had caused the
leak which led to the explosion then Mr Sutton (and correspondingly those who
employed him) were not legally liable for any consequences. I was referred to
Gloag and Henderson - 10th Edition p 509 under the heading “Duty of Care”.
The proposition which the defenders drew from this citation was that a duty of
care is not owed to the world at large but to those to whom injury
may .reasonably and probably be anticipated if the duty is not observed. As a
statement of general principle that does not cause me too much difficulty. The
extension of the foregoing formulation of the principle which was urged upon me
was that legal liability is limited to those consequences of our acts which a
reasonable man of ordinary intelligence and experience so acting would have in
contemplation. The kind of injury sustained and the manner in which it was
sustained should be reasonably foreseeable but the precise chain of events
leading up to the particular accident need not be foreseeable. Negligence is not
to be equated with carelessness for one can be careless although it is not
anticipated that any harm will result from the careless act. Again in general I can
see nothing exceptionable about those assertions.
The defenders sought to analyse the case of Hughes v The Lord Advocate
1963 S.C.(H.L.) 31. In that well-known case small children intermeddling with
an allurement which had been left accessible to them resulted in one of the boys
787
being injured by fire following upon an explosion. The fire arose from an
unusual and intrinsically unlikely set of circumstances. However it was found
that burning (the kind of injury actually sustained) and the manner in which it
was sustained were reasonably foreseeable. However the House of Lords held
that whereas the events leading to the injury might have been unforeseeable the
danger was not different in kind from a danger arising from fire in some form. A
manhole, lamps and equipment (all involved in the accident) were obvious
allurements to children. At the Proof it had been held that it was reasonably
foreseeable that if the manhole was left unattended (as had happened) children
might enter the shelter. The defenders in this case contended that this means that
the manner in which the accident came about was reasonably foreseeable.
However this is rather simplifying the situation. All the finding in fact indicates
is that the first step without which the accident could not have occurred was
foreseeable. The defenders contended I think with some justification that there
was never any doubt that the accident had been caused by a lamp left in the
manhole and it is only the particular way in which the lamp came to be
implicated in the disaster which was unforeseeable. It should be noted that the
Lord Ordinary held that it was reasonable to anticipate that danger would be
likely to result from interference by children with the lamps that had been left
unattended. The anticipated danger was formulated in the Inner House by Lord
Guthrie as being “The Lord Ordinary had held that it should have been
anticipated that a boy might in the circumstances fall into the manhole and
sustain injuries by burning from the paraffin lamp”. Thus the danger to be
anticipated had become a rather more comprehensive narration of what actually
happened. What the defenders argued was that the essence of the House of
788
Lord’s decision was that the human activity which converted the potential danger
into actual injury was entirely foreseeable. Lord Guest in his opinion in the
House of Lords observed “the explosion was an immaterial event in the chain of
causation. It was simply one way in which burning might be caused by the
potentially dangerous paraffin lamp”. However the defenders insisted that the
decision in Hughes was dependent on the finding that the nature of the injury,
that is to say burning, was foreseeable.
An observation of Lord Reid in Hughes is also interesting. He said “no
doubt it was not to be expected that the injuries would be as serious as those
which the appellant in fact sustained. But a defender is liable, although the
damage may be a good deal greater in extent than was foreseeable.” I mention
this because the defenders seemed to be striving to suggest at points in their
submissions that Mr Sutton could never have anticipated that any slackness in
carrying out his particular job could ever have resulted in the massive catastrophe
which in fact occurred. If an act which could potentially and foreseeably cause
injury is committed the person at fault cannot limit his liability by seeking to
estimate and restrict the degree of injury which he supposes might result.
Lord Reid did concede that “the intrusion of a new and unexpected factor could
be regarded as the cause of the accident rather than the fault of the defender”.
The defenders said that in Hughes the cause of the accident was not a new and
unexpected factor. It was the lamp. However it behaved in an unexpected way.
The present pursuers argued that from Hughes what could be derived is that the
possibility of personal injury from the act or omission complained of must be
foreseeable. If you can foresee that people are so proximate to the danger that
personal injury to them can be foreseen then you have a duty not to expose them
789
to that risk.. That proposition in my view seems to be entirely consistent with the
law.
Lord Jenkins in Hughes gives expression to a useful test of foreseeability.
He asks “Is this the sort of thing that is going to happen if I don’t do my job
properly?” Lord Sorn in the Inner House gives a test which although its
application was not followed in the House of Lords may well give a further
indication of the sort of question that can be asked. He asks if the event which
caused the explosion was “an essential event outside the kind of events which
might have been foreseen”. One element in Lord Carmont’s opinion in the Inner
House which I have no hesitation in accepting and which must always be borne
in mind is that each case must depend on it own particular facts. In Lord Morris’
opinion in Hughes he refers to the fact that there does not seem to be anything
“fantastic or highly improbable” in the chain of events which caused the
accident. The test he employs is taken from Lord Keith in Miller v The South of
Scotland Electricity Board.
The defenders referred to the pursuers’ pleadings and to the fact that the
pursuers aver that under the contracts the contractors, Score, had warranted that
the work would be performed competently and there were specific stipulations
that the contractors would ensure that all employees should conform and abide by
Company procedures and regulations pertaining to safety. The pursuers also aver
that it was a requirement of the pursuers in terms of their contract that blind
flanges should be fitted securely to open ended pipework after the removal of an
pressure safety valves. The defenders did not challenge the averments as
narrating the relevant contractual conditions but disputed that these were safety
requirements. I find that a difficult proposition. Apart from other considerations
790
the fitters knew that the work was regulated by the permit to work system which
is one of the principal safety requirements on the platform. The permit for the
maintenance of PCVs provided that a blind flange was to be fitted to open
pipework (see number 12/233 of process). The pursuers also aver that one of the
reasons for the said requirement was to prevent a leakage from pipework in the
event of the inadvertent admission to it of hydrocarbons.
The defenders make the point that a fitter was entitled to suppose that if a
valve was ever to be exposed to other than incidental passage of gas - that is
exposed to full system pressure - it would first be pressure tested. However the
implication of that is that a valve fitter is entitled to suppose that if he fits the
valve incorrectly his inadequacy will be discovered by pressure testing before the
flange is exposed to serious pressure. This assumes a great deal of reliance and
certainty in any system of pressure testing. Indeed the very existence of a system
of pressure testing may emphasise how important it is to check that through
inadvertence or otherwise flanges have not been fitted insecurely.
The defenders argued that the possibility of the flange being exposed to
system pressure was highly improbable. Witnesses gave evidence that operators
would not deliberately re-pressurise a pump with the PSV missing. It was said
that it would be equally improbable given the elaborate safety systems that a lead
operator would not know that a PSV was absent.
It should be noted that the evidence showed that there is always thought
to be a danger when pipework is breached. That is no doubt why there is an
elaborate system to deal with such situations by flanges, valves, spading and
pressure testing. The point that was being made was that it is always necessary
to be careful when breaking into hydrocarbon.
791
The defenders claimed that the pursuers had nowhere averred that there
was a foreseeable risk of fire or explosion. However if there was one plain fact
in the case it was that the pursuers were attributing explosion and the consequent
fire to an incorrectly fitted blind flange. It is implicit in the pursuers’ pleadings
that Mr Sutton knew or ought to have known he was creating the danger which
caused the disaster if he did not tighten the bolts of the blind flange properly.
Whether or not the matter can be proved is another question but after Proof
lasting for years I doubt if the defenders could have been in any doubt as to the
pursuers’ case on this matter. Another approach taken by the defenders was that
it is essential to the pursuers’ case as pleaded that Mr Sutton must have known
that if he did not tighten the blind flange there was a risk that someone would
inadvertently re-pressurise the pump. It is of course contended that the pursuers
have not proved that it was foreseeable that someone would attempt to re-
pressurise the pump when the valve was missing. However if it were shown that
it was foreseeable that there was a risk that a dangerous quantity of gas was
likely to escape if the flange was not properly tightened I cannot see that the
further refinement that the fitter should have foreseen precisely how this came
about is needed. The defenders also submitted that it was only by re-
pressurisation that one could get an flammable mass. I think this is not a very
useful point. The flammable mass that is related to the particular explosion that
the pursuers say occurred is of course related at least in the pursuers’ view on the
kind of flammable mass that would be created upon re-pressurisation. It is also
related to the fact that in traversing the module the gas cloud would have to pass
gas detectors. Because it may not be easy to create flammable clouds at
particular detectors does not mean that there could not be a flammable mass
792
locally. In any event it cannot be asserted that even a small escape of
hydrocarbon does not pose some risk of fire of explosion. The whole thrust of
the evidence is that hydrocarbon is highly unstable and is, if uncontrolled, at least
to some degree a danger. I would be surprised if an experienced valve fitter like
Mr Sutton working on oil platforms did not realise that even a small escape of
hydrocarbon was undesirable because of its volatile nature. Whether that takes
the pursuers far enough of course is the critical question. There is force in the
view that the re-pressurisation of the pump with the PSV missing is an abnormal
procedure and a valve fitter might not even consider that particular possibility.
None of the witnesses from the production operating staff on the platform claim
to have ever seen a pump re-pressurised with a PSV missing. To do this would
be bad practice. Indeed Mr Henderson thought that it would be hazardous. On
the other hand Mr Murray thought that it might be done in dire circumstances
with the approval of the OIM. Mr Bollands also thought that if such an irregular
practice were ever to be followed it would require the approval of a higher
authority than Mr Vernon. As to a valve fitter it might be questionable if he
would have any experience at all of the detailed procedures for the re-
pressurisation of a condensate injection pump.
The defenders cited to me the case of Maloco v Littlewoods Organisation
Limited 1987 S.C.(H.L.) 37. While contractors were doing work connected with
the conversion of a cinema to a supermarket it became clear that young persons
were overcoming the security of the building. The building had been secured at
night but the miscreants were breaking in. Eventually the intruders set fire to the
building causing serious damage to adjoining buildings. Their owners sued the
owners of the cinema. The House of Lords on appeal held that there was no
793
general duty to prevent a third parties’ deliberate wrongdoing even although
there was a high degree of foreseeability that it might occur. This was modified
in relation to the special circumstances of an occupier who negligently allowed a
source of danger to be created on his land. The matter was one for the facts of
each case although cases where liability would arise were likely to be rare.
However it was held that the defenders were not liable in the case under
consideration since if there was a fire risk they had no means of knowing that it
existed. Lord Mackay of Clashfern in his judgment made the important
observation:
“It is plain from the authorities that the fact that the damage, upon which
a claim was founded, was caused by a human agent quite independent of
the person against whom a claim in negligence is made does not, of itself,
preclude success of the claim, since breach of duty on the part of the
person against whom the claim is made may also have played a part in
causing the damage”.
Another passage in Lord Mackay’s judgment of possible importance is:
“human conduct is particularly unpredictable and every society will have
a sprinkling of people who behave most abnormally. The result of this
consideration, in my opinion, is that where the only possible source of the
type of damage or injury which is in question is the agency of a human
being for whom the person against whom the claim is made has no
responsibility, it may be easy to find that as a reasonable person he was
bound to anticipate that type of damage as a consequence of his act or
omission.”
His Lordship then goes on to say that:
794
“The more unpredictable the conduct in question, the less easy to affirm
that any particular result from it is probable and in many circumstances
the only way in which a judge could properly be persuaded to come to the
conclusion that the result was not only possible but reasonably
foreseeable as probable would be to convince him that, in the
circumstances, it was highly likely”.
The defenders sought to derive comfort from the observations of Lord Mackay
that the anticipated action of the third party must be highly likely. If as the
defenders suggest the only critical danger that Mr Sutton had to anticipate was
that some employee of the operators might attempt to re-pressurise the pump
then Lord Mackay’s comments might indeed be highly relevant. The defenders
also argued that if it was objectively improbable that that someone would re-
pressurise the pump Mr Sutton could not be in a worse position if he did not
possess that knowledge than if he did.
Reverting to Maloco what Lord Goff of Chieveley states at page 77 also
has some interest. He is discussing circumstances in which a defender may be
held liable in negligence to the pursuer although the immediate cause of the
damage suffered by the pursuer is the deliberate wrongdoing of another. His
Lordship observes:
“This may occur where the Defender negligently causes or permits to be
created a source of danger, and it is reasonably foreseeable that third
parties may interfere with it and, sparking off the danger, thereby cause
damage to persons in the position of the Pursuer”.
795
I was referred by the defenders to the case of London Passenger
Transport Board v Upson &c 1949 A.C. 155. This case was cited for the dicta
of Lord du Parcq at page 176 of the report. His Lordship said:
“The correct principle was stated by Lord Dunedin when he said ‘If the
possibility of the danger emerging is reasonably apparent, then to take no
precautions is negligence; if the possibility of danger emerging is only a
mere possibility which would never occur to the mind of a reasonable
man, then there is no negligence in not having taken extraordinary
precautions’. I regard this statement and that of Lord MacMillan in the
same case, which was to the like effect as applying generally to actions in
which the negligence alleged is an omission to take due care for the safety
of others”.
The case involved the running down of a pedestrian by a taxi driver and Lord du
Parcq added “A driver is never entitled to assume that people will not do what his
experience and common-sense teach him that they are in fact likely to do so”.
The analysis I have just quoted is in general terms but is supported by judges of
considerable authority.
It should again be noted that Regulation 32(3) of the offshore regulations
say “It shall be the duty if every person while on or near an offshore installation
not to do anything likely to endanger safety or health of himself or other persons
on or near the installation, or to render unsafe any equipment used on or near it”.
This duty is hedged about with criminal sanctions. The defenders did not attempt
to dispute that the statutory duty was absolute and thus they argued that it does
not assist much to decide what is a foreseeable danger at common law. However
796
what the Regulation does do in my opinion is to bring home to those working on
offshore platforms the need in the interests of safety to take great care.
A further case the defenders referred me to was Woods v Duncan 1946
A.C. 401. This case which is mentioned elsewhere in this opinion in another
context involved a submarine undergoing diving trials. When the submarine was
submerged a torpedo officer opened a rear door of one of the torpedo tubes not
realising the bow-cap was open. Accordingly the submarine sank. The mistake
had occurred at least in part because a test-cock which had been painted had
stuck. It was held that those responsible for painting although negligent in the
painting operation had no reason to suspect that the blocking of a hole with paint
would be dangerous to the personnel of the submarine. In the House of Lords,
Lord Russell observed that he agreed with the view of the Court of Appeal that
although the contractors were negligent their negligence was not the cause of the
accident. He accepted that if the test-cock had worked the Torpedo Officer
would not have opened the relevant door. Thus to that extent the condition of the
instrument lead to the accident but notwithstanding this if the bow-cap had been
shut the accident would not have happened. What caused the accident was the
double event. However the core of Lord Russell’s opinion is that the contractors
could not have foreseen that the choking of the test cock could have endangered
the lives of those aboard the submarine. Thus the case is, like so many in this
area of the law, very much fact driven. It has to be noted that in Woods the
contractors were painting a ship which task would not on the face of it suggest
serious safety considerations. It was held in effect that they had no reason to
know or anticipate the safety function of the test-cock. The defenders contended
797
that Score had no reason to anticipate that the function of the blind flange could
include holding fast against the system pressure.
The defenders placed great emphasis on the fact that many witnesses
qualified to discuss the matter were not asked what they considered to be the
function of the blind flange. However that is not to say that there was not a mass
of evidence making the general function of a blind flange fairly clear. If the
defenders thought that the flange had a limited specific function rather than a
general function it was of course open to them to develop a challenge on this
point by cross-examination of any witnesses they considered could support their
view. It has to be noted that before the witness Todd ventured an opinion on
what he thought might be the function of the PSV 504 he was asked what
purpose there might be in fitting a blind flange to open pipework and he replied
“that is a precaution which we took on every piece of pipework”. Mr
MacDonald testified that even small bore water pipes would be fitted with blind
flanges. Mr Todd when asked specifically why blind flanges would be fitted to
the PSV piping answered that it was to prevent any leakage of fluids past the
isolation valve escaping to the atmosphere. Thus he gave an illustration of why
they might be fitted. Nobody asked him if that was the only purpose of having a
blind flange. He no doubt thought of the most likely contingency. Also it must
be noted that it was thought that even seepage from the isolation valve ought to
be prevented. Mr Todd did say that the fitting of blind flanges to PSV was an
invariable requirement and that fitted means “fitted properly”. Indeed he goes on
to declare “It should be put in place and secured as it was meant to be secured,
tightly, to prevent gas escaping or any fluids escaping from the open pipework”.
It would perhaps be odd that if a fitter was aware that the flange was there to
798
prevent escape of gas or fluids he should think that the only such fumes or fluids
it might be required to trap were such as might escape from seepage. Moreover
if this was in fact Mr Sutton’s expectation he may well have required to surmise
it since there was no evidence that he had ever been told that there was this
limited function. Even if he knew that an escape of gas can be dangerous and
that one reason the blind flange was there was to prevent seepage it would be a
curious definition of his duty to take care if this depended on a fine calculation of
how much gas could seep past the GOV and the potential of that particular
amount for causing fire or explosion. The duty to take reasonable care for one’s
neighbour cannot be founded on such narrow considerations.
Counsel for the defenders suggested that one reason why a blind flange
was fitted to prevent seepage escaping was to avoid the risk of false gas and fire
alarms. He did not cite any evidence in support of this supposition. Moreover if
a seepage was sufficient to set an alarm off it would be safer to avoid such a
contingency being possible by fitting the blind flange properly. If an alarm goes
off it is considered sufficiently dangerous to merit immediate investigation.
When the valve is removed the pipework will be open for a short time
while the blind flange is being fitted and certainly it was never suggested that this
creates any particular danger. This may indicate that the kind of escape that is to
be prevented is such as could occur over a material period and therefore would
be more likely to generate a dangerous quantity of gas. The question of valve
security, potential seepage, and consequent explosive mass was not explored in
any depth in the evidence and if it had been discussed with Mr Sutton during his
lifetime it is difficult to suppose it would have meant much to him.
799
The defenders suggested that there was no evidence that a blind flange
was designed to withstand system pressure but this is not quite so for there was
evidence about the Nowsco tests which suggested that a properly fitted blind
flange would be leak-tight when subjected to the equivalent of such pressure.
On the other hand the same tests established that all combinations of flange and
seal types would give what are described as gross leaks if the bolts were only
finger tight (Mr Standen’s Report which is number 13/79 of process). It should
perhaps also be noted that there was no evidence that the flange was likely to
warp and looking at the weight and solidity of the flanges I should expect that
any kind of warping would be most exceptional.
The witness Mr Reid had a more expansive idea of the purpose of a blind
flange. He stated that the purpose was “the same as any line, you don’t want an
escape of the medium into the module or whatever”. I have no reason to suppose
that the awareness of Mr Sutton was any less than that of Mr Reid. The
defenders suggested that Mr Reid may have had water lines in mind but I think
that is a bit far fetched. In any event Mr Sutton could hardly have expected an
escape of water from the relief line.
The defenders’ witness Mr Pirie was a valve technician with the Wood
Group. It is worth mentioning that he confirmed that the normal practice for the
fitting of blind flanges was to tighten them by flogging or the use of combination
spanners. He agreed that one of the reasons for fitting a blind flange was to
prevent leakage from the pipework. It should be noted that this answer was
prompted by a leading question and of course he was only referring to one of the
reasons.
800
Mr Rankin also had comments to make about blind flanges. He said that
he saw no difference in principle to fitting a flange to a valve removed for testing
and fitting one to the pipework. On the other hand this was in the context of the
valve being tested under pressure. As he stated “a blind flange must be used to
contain the pressure within the body of a valve”. He makes what is claimed by
the defenders was a distinction between a situation where a foreign substance is
to be introduced to a valve for testing purposes. He says in relation to the open
pipework the purpose of the flange is “to stop any accidental spillage from the
system, or to prevent any dirt entering from outside”. He considers that if a
valve is supposed to contain pressure it ought to be pressure tested. On the other
hand he seems to be acknowledging that one purpose of a blind flange is to
contain such material as might be expected to arrive at the flange. Any
hydrocarbon that escapes from the pipework into the atmosphere is after all an
accidental spillage and the flange was there to prevent that happening. The
defenders’ Senior Counsel expressed surprise that Mr Rankin was not examined
more closely about what was to be expected from a blind flange particularly as in
the pleadings he shares the imputed blame for the accident.
The purpose of the submissions of the defenders I have been discussing
was to convince me that the pursuers have failed to prove that the kind of
accident that may have occurred from an escape of hydrocarbon at the blind
flange fitted by Mr Sutton was not such as would have been anticipated by him
as a potential risk which could arise from the manner in which he fitted the blind
flange. I have no doubt that it probably did not cross Mr Sutton’s mind that any
action or omission on his part could expose the platform and its personnel to the
kind of catastrophe which actually occurred. However because the consequences
801
of an act are unexpected in scale would not be enough to exonerate a person who
otherwise had been negligent. In this area of the law a good starting point is the
observation of Lord du Parcq in London Passenger Board (which I have already
referred to above) where his Lordship said “if the possibility of the danger
emerging is reasonably apparent then to take no precautions is negligent”. It
must be noted that Mr Sutton was working in what was intrinsically a very
dangerous situation if normal safety precautions were ignored. The situation is
quite different to the one that arose in Woods. There the painters were carrying
out work which was essentially innocuous and they could not have conceived
that any careless painting might have caused the submarine to sink. Even if they
had been aware of the specific function of the test-cock it was not to warn if the
bow was open but to check the water level in the tube when torpedoes are fired.
It is well known to those working on a platform that the most critical safety
concern is to contain the massive quantities of hydrocarbon that are circulating
around the platform. Moreover that there is a risk of fire or explosion if any of
this escapes is very evident. On the production modules there is an array of fire
and gas alarms. If a workman is faced with a situation where a quantity of
hydrocarbon is at risk of escaping I do not think it behoves him to say that he
was not aware of the precise amount of the substance it needed to form an
explosive mass at any point on the platform. He well knows that it is not his
function to calculate precise risks arising from a particular operation. His
responsibility is to take the precautions laid down by the platform management.
There are rigorous statutory safety regulations which bring home to him how
important it is for him to carry out his work safely. There is a complex system
laid out by the defenders to control safety. Every person working on the
802
platform knows the important function of the permit to work system. There are
hot work permits and cold work permits and it is not a difficult inference to
understand that the special requirements of hot work permits are connected with
the prevention of fire and explosion. In the case of PSV calibration the Permit
which regulated the work carried out by Mr Sutton actually specifies that blind
flanges were to be fitted as a precaution. There was no doubt that the proper way
to fit blind flanges is to flog the bolts or to tighten them with a combination
spanner. There is no point in fitting them if they are not properly fitted. Apart
from any other consideration it would seem to me to be careless in the
circumstances of work on an oil platform to ignore a safety instruction stipulated
by the employers. The valve fitter can hardly be expected to be in a position to
assess what dangers may or may not arise from the system of working on the
platform. I do not think it is for him to consider what the purpose of a blind
flange is or what danger there is of hydrocarbon accidentally being introduced to
the relief line. This surely would be for management. It is not for the fitter to
consider “if I do not do this job as I am supposed to there is no obvious risk”.
How is he supposed to be sure about this. The appropriate approach in a
situation where generally potential dangers abound is to think “the Management
have asked me to take a particular precaution with safety implication so I had
better do what they have asked me to do and not try and decide the matter for
myself”. I do not think there is any doubt that the managers expected a blind
flange to be properly fitted so as to exclude any hydrocarbon that may have got
into the line accidentally. It may be that the possibility of an operator
deliberately introducing pressure into the valve when the PSV was missing
would be relatively remote. However I do not require to consider what would
803
have been the result if this had occurred since my view is that Mr Vernon, if he
re-pressurised the pump, did so as an act of inadvertence. Such acts are always
conceivable and they can present themselves in most unexpected ways. The
platform management (and consequently Mr Sutton) could not anticipate
precisely what accidental events might put more pressure into the pump than was
intended. I do not see this case, as some other cases which have been mentioned,
as being one where only the agency of a third party could have caused a danger.
There could have been a variety of circumstances causing a small or large but at
least dangerous amount of hydrocarbon to enter the pump and this could have
been caused not by human intervention but by mechanical problems such as a
GOV allowing more seepage than was normal or perhaps not closing fully. The
important point was that the pump was still connected with the system and it was
clear from the evidence that any breach of the flow system creates a situation
requiring special care. Moreover the evidence also showed that it was part of the
general system to have checks and counterbalances. Thus if a valve closed this
was generally not relied upon to seal the system but flanges or a second valve
would be in place as an extra precaution. In my view the blind flange sealing the
relief line was at the end of the day part of the layer of precautions. Emphasis
has been placed on pressure testing. This seems to me to be an additional
precaution to ensure in situations where pressure is to be reintroduced to a line
that the flanges have been fitted properly. Pressure testing is not meant as a
substitute for correct fitting of a flange but an additional safety measure. Of
course the provisions for sealing a blind flange in a valve calibration operation
did not require pressure testing. We do not know why. It may be that because
the valve is only there as a short term measure or because the likelihood of the
804
valve being subjected to extreme pressure is remote that it was not considered a
practical necessity. It should be again noted that the Nowsco tests showed that a
properly fitted flange should be able to contain such pressure as would develop
on re-pressurisation. Of course once the pump began to pump normally larger
pressures could develop and it may need pressure testing to be sure that the
flange could handle these. However I think OPCAL were entitled to assume that
any precaution aimed at assisting in the sealing off the process line would at least
function to anticipated capacity in that direction. The fact is that assuming a leak
from an ill-fitting blind flange caused the accident then if it had been fitted as the
Lead Production Operator intended when he issued the permit to work the
accident would not have happened. I think OPCAL were entitled to expect that
the safety systems they laid down would operate to best effect and that workmen
would not decide to depart from them. Indeed the defenders make the same
point in relation to the completion of the permit to work forms when they argue
that production staff should not off their own bat seek to adjust the terms of the
prescribed forms.
7.2.3. Novus Actus Interveniens
The defenders argued that since what is alleged to have occurred at the
accident was not foreseeable to Mr Sutton he had no duty to take care in respect
of what is said against him. However as a quite separate point the defenders
argued that there was a break in the chain of causation to the effect that any
slackness on the part of the valve fitter was not a cause of the accident. The
defenders argued that an act which is a sine qua non in the chain of causation is
not necessarily to be regarded as rendering the actor liable if the chain of
805
causation is interfered with and completed by the act or omission of a third party.
Senior Counsel for the defenders suggested that the prerequisite for liability is
that the act complained off should be a direct contributor to the harm even if the
harm would not have occurred without the earlier event. I do not think I can
disagree with these generalities.
I was referred to the case of McKew v Holland & Hannen and Cubitts
1970 S.C.(H.L.) 20 on appeal to the House of Lords. A workman had been
injured by an accident at work for which his employers were admittedly
responsible. As a result of that accident his leg was left weakened. Three weeks
later he sustained a further accident while he was descending some stairs and this
was attributable to his weakened leg. The House of Lords affirmed the judgment
of the Second Division in holding that the pursuer ought to have realised that
certain precautionary steps were needed to descend the stair safely, that he acted
unreasonably in omitting to take these steps, and thus his unreasonable conduct
was a novus actus interveniens breaking the chain of causation. It was noted by
Lord Reid that foreseeability did not come into the situation. Lord Reid said (at
page 25) that if a man is injured in such a way that his leg may give way at any
moment he must act reasonably and carefully. However it has to be observed
that in the case being considered the pursuer was aware of all the circumstances
dictating that he required to take care. Thus the reasonableness of his actions can
be assessed without reference to the facts surrounding the earlier accident. I
consider that the test applied by the Court was that the accident was caused
exclusively by the pursuer’s unreasonable conduct. The defenders attempted to
take from this case that if the chain of causation is broken by unreasonable
conduct independent of the first act of negligence then it is immaterial that the
806
earlier wrongdoer may have been able to foresee that the second event could
happen. Lord Guest suggests that what is required to break the chain of events
for which the second wrongdoer is accountable is “a new cause which disturbs
the sequence of events, something which can be described as either unreasonable
or extraneous or extrinsic”. It also has to be noted that the conduct in McKew
which was held to be unreasonable was the conduct of the victim himself.
The defenders also contended that if an act is so extraordinary as to
bebeyond possible identification as being in the natural course of events then that
would bring the doctrine of novus actus interveniens into play.
The next case cited to me by the defenders was Wright v Lodge &c
(1993) 4 All.E.R. 299. A motor car had broken down on the motorway and
while stopped for repair on the near-side lane a lorry drove into the back of it
seriously injuring a passenger in the back seat of the stationary car.
Unfortunately the lorry veered out of control on to the opposite carriageway and
a collision took place which caused a fatality and injuries. The root cause of this
accident was that the lorry had been travelling at excessive speed. The lorry
driver was sued and while admitting liability claimed contribution from the
original car driver. The judge of first instance found that the lorry driver had
been driving recklessly and that this was the sole cause of the accident to dead
and injured drivers. On the other hand in respect of the injured passenger the
judge found that the driver of the car had been partly to blame in that she had left
her vehicle unlit and stationary on the carriageway. The question in the Appeal
was whether or not the negligence of the original driver had also been a factor
causing the accident to the other drivers. It was held that the fact that a driver
was negligent in leaving his car on the carriageway and causing an accident
807
partly by his own negligence did not necessarily render him liable for subsequent
events as a result of another driver’s reckless driving. In the case under
consideration the lorry driver, driving an articulated lorry, had been driving at 60
mph in thick fog. The answer would have been different had only careless
driving on the part of the lorry driver been involved. However what took the
lorry onto the opposite carriageway was not so much the collision but the
reckless speed of the lorry. Thus the presence of the lorry on the opposite
carriageway was held to be wholly attributable to the reckless driving of the lorry
driver. Given that determination of the facts it is difficult to see how any other
result could have been arrived at than what the trial judge decided. Lord Parker
in his judgment observed that although there has been much discussion in the
authorities as to the tests to be applied in a case such as he was considering such
tests must be related to the facts of each case. There is in his view no single test.
He considered that the questions to be decided must be determined by applying
common-sense to the facts of each particular case. Although it is not always as
easy as it might appear at first sight to apply common-sense norms to such
complicated matters I agree entirely with Lord Parker that the common-sense
approach is the only safe way forward. However the matter which determined
this appeal was the distinction that was drawn between what might normally be
expected by way of careless conduct and the totally extraordinary implications
when someone drives recklessly. The trial judge, Mr Justice Hobhouse, had held
that the lorry driver had shut his eyes to the obvious risks that existed and that,
Mr Currie contended, was exactly what had happened in the present cases.
“Recklessness” in his submission was gross negligence in the face of obvious
danger. In his judgment in Wright Lord Justice Woolfe comments that in Clerk
808
and Lindsell on Torts the editors suggest the explanation for reckless driving
being treated differently in causation is that deliberate or reckless conduct is so
obviously more blameworthy than carelessness that it can be singled out as being
the substantive cause. However even that approach in my view is not so easy to
justify because there are many cases where the relative contributions of joint
wrongdoers to the accident are very disproportionate. The justification of course
would be that a distinction has to be made between quality and quantity but this
is not always easy to discern.
The defenders of course as I have already stated were urging me to find
that Mr Vernon was acting recklessly in that he knew that the PSV was missing
but nevertheless violated safe procedure by jagging the pump without at least
pressure testing (assuming of course that he did jag the pump) or if the fact was
that he did not have it in mind that the PSV was not in place then that represented
a gross failure to take account of his responsibilities and to keep himself
informed as to what was happening in the production modules.
The next case the defenders referred m to was Marvin Sigurdson v British
Columbia Electric Railway Company Ltd 1953 A.C. 291, a decision of the Privy
Council. In this case a street-car driver ran into the appellant’s motor car which
was stationary on the street-car track in the middle of a junction as the driver
waited for an opportunity to complete crossing the road. The judge of first
instance found that the street-car driver was solely to blame in not keeping a
proper lookout but on appeal the motor car driver was held to be equally to
blame. The respondents contended that where one party knows of the dangerous
situation created by the negligence of another but fails to take reasonable steps to
avoid the danger he is generally solely liable. On the other hand if that party did
809
not actually know of the danger, or by his own negligence or deliberate act has
disabled himself from becoming aware of the danger, he can only be held liable
for a proportion of the resulting damage. It was held that there is no warrant for
such a far reaching proposition. The implication that the defenders sought to
take from this case was that if Mr Vernon did not know that the valve was absent
this was due to his own negligence and he could not hide behind that negligence
to deprive the defenders of a result in respect of Mr Sutton’s part that would
otherwise be available to them. I must confess that I find that argument rather
difficult to follow. If a dangerous hole is left on the pavement and someone falls
into it because by looking at some distraction he has precluded himself from
being aware of the danger is he totally excluded from some degree of recovery.
The argument may make sense if what is being suggested is that only
Mr Vernon’s reckless conduct or what is described as ‘gross negligence’ could
have prevented him being aware of the risk represented by the missing PSV. To
keep oneself in the dark deliberately would of course be akin to wilful
misconduct.
In relation to the question of recklessness I was referred to the Stair
Memorial Encyclopaedia of the Laws of Scotland, Volume 7, paragraph 82 on
page 69. For criminal liability it is suggested that for there to be recklessness it
is required that there be a culpable indifference to the consequences, or a
blameful disregard of the results, or a total indifference to and disregard for the
safety of the public, or an utter disregard of what the consequences will be, or a
culpable disregard of the consequences. There were other references in the text-
book. It was argued that the two basic notions behind the authorities were a very
810
high degree of indifference or disregard relative to the potential consequences of
the conduct in question or alternatively gross negligence.
The final case I was referred to by the defenders in relation to this part of
the case is Knightly v Johns &c (1982) 1 W.L.R. 149. A motor car driven
negligently in a tunnel overturned. The Police Inspector who took control of the
locus forgot to close the tunnel immediately to traffic as required by police
procedures. He ordered two constables to go back for that purpose and to fulfil
that task they motor-cycled against the traffic flow. The plaintiff was injured
when he thus travelled round a blind bend. It was held that the original motorist
was not responsible because the new and direct cause of the plaintiff’s accident
(the conduct of the inspector) broke the sequence of events. The remarks of
Lord Justice Stephenson in the Court of Appeal are interesting because he says:
“I conclude from these rescue cases that the original tortfeasor, whose
negligence created the danger which invites rescuers, will be responsible
for injury and damage which are the natural and probable results of the
wrongful act and that those results include injury and damage of a kind or
class which might normally be foreseen or contemplated, although the
particular accident could not be expected”.
He seems to accept these same principles as applying to chain of causation cases.
After a long analysis his Lordship sees no reason for departing from the
established concept of a new cause breaking the chain from another link in the
chain. He repeats what has repeatedly been said that human beings, however
well trained, when they have to cope with a crisis, mistakes and mischance are to
be expected. He concludes by finding that (following Lord Reid in Dorset Yacht
Company) in the long run the question remoteness of damage should be answered
811
as has often been stated, not by the logic of philosophers but by the common
sense of plain men. The case of Knightly shows that whereas recklessness
represents one end of the spectrum in assessing novus actus a chain of events not
perhaps involving negligence can be so tortuous and extraordinary to make the
accident too remote from what may have originally preceded it.
The pursuers referred additionally to The Oropesa 1943 Probate 42. In
that case two steam vessels had come into collision and although one, the M.R.,
was badly damaged her Master thought she would survive. He had sent 50 of his
crew in two boats to assist the Oropesa. Later he decided to go himself to the
Oropesa with a number of men. The weather roughened, the boat capsized and
nine men drowned including an engineer. The parents of the engineer sued the
owners of the Oropesa for the loss of expectation following upon the death of
their son. It was held that the Master of the Oropesa had acted reasonably and
that the death was not the result of novus actus interveniens but was directly
caused by the collision. Lord Wright in his judgment (page 37) states that
human action does not per se sever the connected sequence of acts. For the rule
to apply there must be a breach of the causal chain (I doubt if that would ever be
disputed). If the interveniens acts unreasonably it was accepted that there can be
a breach in the causal chain but Counsel for the pursuers contended that one
never gets to that point in relation to Mr Vernon because the causal chain was
never broken. According to the submission it is necessary first to ask is there a
new cause and this is a question of fact. If there is a new cause - a break in the
chain of causation - it would be necessary then to ask if the interveniens
producing that new cause acted reasonably. It was said that there was no break in
the link between Mr Sutton’s negligence and Mr Vernon’s conduct. Mr Sutton
812
could be sued because despite what Mr Vernon did or did not do Mr Sutton’s
negligence remained a contributory cause of the accident. I was referred to a
further passage from Lord Wright in Oropesa where he approves the statement
“Cause and consequence in such a matter do not depend on the question whether
the first actions which intervenes is excusable or not but on the quest whether it
is new and independent or not”. In the light of the authorities I have no difficulty
in accepting that authoritative encapsulation of the law.
The pursuers further referred me to Rouse v Squires (1973) 1 Q.B. 889.
It was held in that case on appeal that if a driver creates an obstruction on the
highway which creates a danger to other road users (including those driving too
fast though not those who may deliberately or recklessly have driven into the
obstruction) then his negligence contributed to the causation of an accident
although the immediate cause was the negligent driving of another driver. In any
event the essential finding of Rouse was that if there is an act of negligence and
the consequential source of danger still exists to a substantial degree at the time
of a second act of negligence, and thereby contributes to the accident then a
defence of novus actus interveniens can never apply. In Admiralty
Commissioners v S.S. Voluta Lord Birkenhead said essentially the same thing.
The final case to which the pursuers referred me was Haynes v Harwood
(1935) 1 K.B. 146. I was referred to this case because of the dicta of Lord Greer
who said:
“If what is relied upon as novus actus interveniens is the very kind of
thing which is likely to happen if the want of care which is alleged takes
place, the principle embodied in the maxim is no defence. The escape of
hydrocarbon because the flange was loose is of course the kind of
813
eventuality a valve fitter could have anticipated if a flange is not properly
tightened”.
Lord Greer continued:
“It is not necessary to show that this particular accident and this particular
damage were probable; it is sufficient if the accident is of a class that
might well be anticipated as one of the reasonable and probable results of
the wrongful act.”
The defenders’ submissions about novus actus interveniens undoubtedly
raise difficult and interesting questions. The main thrust of their argument of
course is derived from their principal submission that Mr Vernon either acted in
deliberate contravention of the safety procedures or at least in a manner that was
grossly negligent. If I had agreed with this I should have had to decide the
important question as to whether I could accept that an act which is wilful or
reckless wrongdoing will break the chain of causation. However I am not in that
position. As I have set out above Mr Vernon in my view had let it slip from his
mind (that is assuming it was ever there in the first place) that the PSV was
missing. He had arrived that very evening on a fresh tour of duty. He probably
had to familiarise himself with a number of matters. Given OPCAL’s systems he
probably had proper opportunity to discover that the valve work was progressing.
There is at least a possibility that some time in the evening he would have known
this or had the opportunity to discover it. On the other hand given that the
pump A had been withdrawn from service for maintenance and isolated the
situation in relation to the PSV may not have impacted very strongly in his mind.
Later in the evening he was confronted with what on any view could have been
described as a minor crisis. The pump which pumped out the condensate
814
production stopped working. The defenders suggested that he had ample time to
deal with the situation comfortably. However the matter may have caused him
concern and he certainly had to take decisions. When pump B did not restart
Mr Vernon decided that he would bring pump A back from maintenance and
bring it back to production. He knew that to bring a pump back into production
when the PSV was not available was unacceptable practice. Nevertheless he
confidently and openly made arrangements to re-introduce pump A to the
system. He informed Mr Bollands and Mr Clark of his intentions yet never
mentioned the matter of the PSV. He made no attempt to consult senior staff
who were available on the platform. If he knew that the PSV was not in place he
was openly and unnecessarily exposing himself to reprimand by his superiors and
that in a situation when he could have hoped for a promotion. He arranged for
Mr Clark to restore the electricity and yet if he had known that the pump was
also isolated under a PSV permit his actings would not have made sense because
the pump would have remained isolated under the PSV tags. It is clear that his
measures took place only under one permit or permit application. The reason
why Mr Vernon had allowed the position in relation to the PSV to escape his
mind (if this is the case) will never be known. However I cannot conclude that
his actings represented gross negligence or recklessness. If he had forgotten that
the PSV was not in place he was not showing a reckless disregard for the risks
since such risks had never entered his mind. Assuming he was guilty of
inadvertence this is a serious matter for someone in his responsible position but a
serious degree of inadvertence is not the same as a reckless or even irresponsible
state of mind.
815
Unlike the novus actus interveniens situations set out above, Mr Sutton
(assuming he only put the flange on finger tight) had deliberately ignored
instructions which he knew or ought to have known had safety implications for
the platform. It is difficult to know what he was thinking. The flange was heavy
and it is likely that because of cramped space he found it difficult to hold the
heavy flange in position and to use flogging or combination spanners. He could
have called for extra assistance if this were the case. He may well of course have
thought that the flange would only be on for a few hours and that he would be
present during that time if any problem developed or was likely to develop at the
relief line. Were that so when he discovered that the flange was going to be left
in position overnight he should have taken steps even at that stage to tighten it
properly. It is very sad and unfortunate that Mr Sutton has not had the
opportunity to give his own version of events but I have to proceed on the basis
of the evidence available. As I have already said one purpose of the flange being
fitted was to exclude foreign substances from escaping from the pump and
entering the Module. If the flange had been properly fitted the probability is that
it would have fulfilled that purpose and the accident would not have happened.
As it happened the loose flange remained a danger even at the time of the
accident albeit that Mr Vernon’s actings had intervened. The complex events
leading up to the escape of hydrocarbon perhaps could not have been anticipated
in all their detail. However that some hydrocarbon could escape was perfectly
foreseeable. It was exactly the type of event that was to be feared and the blind
flange was part of the system of protection against such a contingency. As it
happened the introduction of a lethal quantity of gas into the pump required
human intervention but the situation could equally have arisen as a result of some
816
unexpected failure of equipment. A valve could have failed or someone could
have for some unexpected reason accidentally opened the GOV. In the case of
Wright what caused the second accident was that the lorry veered onto the
opposite carriageway. This was held to be a different type of accident to what
might have been expected from the fact that a car had been left stationary in the
inner lane. It was not only a question of scale of injury. Only a lorry travelling
at an excessive speed could have crossed to the opposite carriageway (or so it
was held). Supposing a bus full of passenger had been travelling at a reasonable
speed but collided with the stationary motor car killing a substantial number of
people then although the scale of the claim against the car driver would have
been materially different it is likely she would have been held liable if no
recklessness was involved. As I have already said an escape of foreign matter is
just the type of thing that would be expected if a flange is left loose. All that was
probably totally unforeseen was the scale of the disaster. Even allowing for the
negligence of Mr Vernon the accident would not have happened if the flange had
been fitted as instructed. At the end of the day there were two causes of the
accident both of which could properly be categorised as direct. One was the fact
that the pump was re-pressurised at a time when not all safety measures were in
place. The other is that when this happened the blind flange had not been fitted
so as to perform its proper function of sealing off the relief line. The chain of
causation stretching from the original fitting of the flange had not been broken.
When condensate entered the pump at that point of time the actings of Mr Sutton
were for the first time put to the test and the absence of a properly fitted flange
allowed it to leak out. The effects of the negligence of Mr Sutton and that of Mr
Vernon co-existed and they were both operative in connection with the accident.
817
One can feel quite sorry for Mr Sutton. He was engaged in a relatively
simple operation and no doubt he thought that if he cut a few corners not much
harm was likely to result. It may even be that he simply did not concentrate and
do his work carefully. Unfortunately the worst that could have been conceived
then happened because of his slackness.
The pursuers also made the point that the defenders had an obligation to
plead a case of novus actus interveniens if this is part of their defence because
they have the onus of proving it (S.S. Baron Vernon v The Canadian Pacific
Railway Company 1928 S.C.(H.L.) 21). This point might have a degree of merit
although, if so, how it would operate in a case like this is arguable. However I
need not decide the issue on a technical pleading point because for the reasons I
have set out above I am satisfied that the defence is ill-founded.
7.3. The Jagging of Condensate Injection Pump A
7.3.1. General
The pursuers’ case, of course, largely depends for its validity on the
proposition that the accident was caused because Mr Vernon in attempting to
start Condensate Injection Pump A tried to re-pressurise it by jagging at a time
when PSV 504 was missing. If the pursuers cannot prove that Vernon must have
been jagging the pump then subject to one matter their case must collapse. I
introduce a note of qualification because there is the pursuers’ separate argument
that if the cause of the accident is not established then they would still be entitled
to recover under the indemnities.
818
One fact dominates this area of dispute and that is that there is no direct
evidence that Mr Vernon jagged the pump. No-one claims to have seen him do
so. Thus proof of the facts on this topic must depend on inference. There is of
course the fact that Mr Vernon was faced with a need to get a condensate
injection pump running and proceeded to the 68-foot level after declaring that he
was intending to start Pump A. There is also the pursuers’ claim that the two-
phase pattern of the gas alarms would only be consistent with the leak having
been caused by a multiple phase process such as jagging the pump. The
pursuers’ contention is that the initial gas alarm was as a result of a gas escape
after the first stage of the jagging process. A second stage of jagging carries out
a few minutes later caused a second escape of gas which not only caused the
second flurry of gas alarms but also was fuel for the explosion.
The general layout of the 68-foot area is conveniently shown in the
schematic number 13/49 of process. It will be seen there that the push/pull
buttons relating to the opening and shutting of the relevant GOVs were situated
on stanchions which placed them about a yard or so from the GOVs themselves.
Each pump had in the same area a running control panel (shown in the schematic
to the right of each pump). Each of these panels was about two feet from its
pump. A pump is started by pushing the start button relating to the pump.
One fact that is not disputed is that at the time of the accident Pump B
had tripped and Pump A had been taken out of production for a proposed planned
maintenance. This meant that Mr Vernon would be concerned to get one or other
of these pumps running as quickly as he could. Failing this there would have
been a serious loss of condensate production. In respect of restarting the pump
that had tripped the operator would there be dealing with a pump already
819
pressurised. To restart the operator would reset the speed selector to manual and
wind the signal off the pump. Then at the control panel JCP 57 the operator
would reset the GOVs which relate to the pump. Then one would proceed to the
GOVs and re-latch them which would have the effect of opening both GOVs.
This would put the operator in a position to try and restart the pump by pressing
the start button. If the pump started the manual speed controller would later have
to be adjusted. Thereafter the pump could be switched back to automatic
running. It was easier if there were two persons involved in restarting the pump
but one person if he worked quickly could restart a pump in a few minutes.
It is plain that after Pump B had tripped Mr Vernon (who had come down
to the pump from the Control Room) together with Mr Richard attempted to
restart Pump B and failed to do so. Thus were it at all possible to bring Pump A
back into commission it would have been an obvious step to take even if efforts
to get Pump B restarted were continuing. After Mr Vernon had attended to his
business with Mr Clark which he carried out from the Control Room, he returned
to the 68-foot level. There he and Mr Richard were shortly thereafter joined by
Mr Grieve although not long afterwards Mr Richard left them when a gas leak
was reported to him. However for at least a short period there would have been
three men available at the two pumps. Mr Grieve for his part seems to have been
engaged in trying to restart the tripped pump and in particular he was engaged in
switching the speed controller to manual, winding it back, and in resetting the
GOVs. Of course each time the pump failed to start or tripped the procedures
which Mr Grieve was attending to would have to be repeated. Mr Grieve did
indicate that it was not all that unusual for a pump which had tripped to be
stubborn about restarting. Once the pump does restart then a red control light
820
goes on to show that the pump is back running. He was there with the intention
of adjusting the speed controller of the pump. On the other hand the witnesses
Henderson and Seddon stated that if it was the intention to bring a dormant pump
into operation it would be expedient to get it re-pressurised as quickly as possible
in case it proved to be needed.
We were told that if a pump has been isolated it was practice to put on the
valve a tag saying “Do not operate”. However we were told very little about the
operation and effect of such a system. If a pump is being isolated then various
ventilation valves require to be opened and these in turn have to be closed when
the pump is restarted although at what stage is not entirely clear. The isolation
procedures in respect of adjusting valves takes about 10 minutes and that of
course is exclusive of the actual de-pressurising. To de-pressurise manual valves
are opened and the hydrocarbon escapes to flare. That particular part of the
process we were told takes about 5 minutes. Then the operator would isolate the
lines that sends this pressure to flare. After that the operator opens the zero vent
line to the atmospheric vent system. This runs out to the flare system without
any other control valves. From start to finish the de-pressurisation procedures
could take up to 2 hours. The defenders claimed that these procedures have some
implications for the re-pressurising of the pump.
Even if a pump tripped and the other pump was pressured-up and on
standby the first step would be to try to restart the pump that had tripped if this
seemed feasible because this is generally easier that trying to start a pump on
standby. The one fact that the operatives seemed to be clear about is that the
pumps were somewhat temperamental both as to their propensity to trip and to
their readiness to restart. A pump on standby would not only be pressurised but
821
would be set at manual speed and wound back to facilitate bringing it back to
operation. If the pump which had not tripped was available but not pressurised it
would be necessary to re-pressurise it before attempting to start it. This was done
by the gradual process called jagging and this involved opening the suction GOV
for short periods on a number of occasions so that a limited amount of
hydrocarbon was introduced to the pump at each stage and the damaging stress
on the pump which would result if all the pressure was introduced at once could
be avoided. During the jagging process the operator could see what was
happening by means of a suction pressure control gauge that was accessible to
him as he jagged. Even if the pump which had been de-pressurised had been de-
pressurised and reserved for a planned maintenance if this programme had not
actually begun the procedure would be firstly to try and restart the tripped pump
and then to retrieve the other pump if the tripped pump could not be started.
Preparing the second pump for re-introduction would be a matter of “major
concern”. As the witness Mr Henderson also said if the tripped pump could not
be restarted, if it was thought helpful in relation to restarting that pump,
electricians and instrument technicians would be summoned to help. In fact just
before the explosion Mr Young, an Instrument Technician had been summoned
to the 68-foot level. Thus the procedure which Mr Vernon is alleged to have
followed would have been perfectly normal had PSV 504 not been absent. It
would not be too difficult to suppose that he would have acted in the fashion the
pursuers ascribe to him were the situation that he did not have in his mind that
PSV 504 had been removed from its site. The situation I have been referring to
would always be accompanied by at least a measure of urgency because
condensate would still be filling the collection vessel. However some time in this
822
respect could be bought by unloading and recycling the reciprocating
compressors thus slowing the condensate flow. It should be perhaps noted that
there was on the local control panel a green light which shone if electrical power
to the pump was switched on.
No re-pressurising of a pump could take place without re-connecting the
air supply (assuming that this had been disconnected) but this would only take a
few minutes. The time required to jag the pump appears to depend to a degree
on the practice of the operator who is doing it and the time seems to vary
between about 30 seconds and 5 minutes. There does not seem to have been an
established procedure in respect of the timing of a jagging process. However it
would be possible to jag the pipe fully in some seconds if this was desired. The
number of jagging procedures required would also depend on how an individual
operator went about jagging. The objective of the procedure was obviously to
avoid a re-introduction of pressure to the pump which was too drastic.
7.3.2. Events at the 68-foot Level
On the evening of the accident Pump B tripped just before 9.45pm. Upon
receiving the alarm that the pump had tripped Mr Bollands alerted Mr Richard
and at the same time Mr Vernon “grabbed his helmet” and went down to the
pump. Mr Bollands did not find Mr Vernon’s immediate concern surprising for
as he said if the condensate injection pump goes down the whole gas plant may
trip so that it is essential to act quickly. Mr Bollands reckons that Mr Vernon had
left the Control Room about a minute after the alarm had annunciated. A further
minute at most would have taken Mr Vernon to the Control Room.
823
So far as Mr Bollands was concerned the next event was that the JCP
Panel alarm went off and he notified Mr Richard. He asked Mr Richard if he had
unloaded the reciprocating compressor but cannot recollect his reply.
Mr Bollands estimates that about three or four minutes had passed between the
pump alarm and the JCP Panel alarm. I think almost all the estimates of time
have to be taken with some caution since it is difficult for witnesses to be
accurate about such short times. I think the JT Flash drum can be discounted as
the source of the explosion since this would have leaked into the 68-foot level.
Moreover Mr Grieve walked passed the JT Flash Drum some short time before
the explosion and noticed nothing remarkable other than that a high level alarm
was indicating.
At the time the pump tripped Mr Grieve had been in the Gas
Conservation Module and he had noticed the radio conversation about the pump
between Mr Bollands and Mr Richard. Some minutes later Mr Grieve went
down to the 68-foot level to see if he could give the men there a hand. All he can
remember is that from the conversations over the radio it was clear to him that
they were not getting the pump started. Nevertheless he regarded this as a
normal routine problem. His estimate as to how long before the explosion he
decided to leave the gas conservation module is from five to ten minutes. On the
other hand he thought that he had only been at the 68-foot level for a few
minutes before the explosion. Walking down to the 68-foot level and passing
through Module C he noticed nothing unusual. This might suggest that there was
no appreciable quantity of gas at the east end of the module at the time when he
passed otherwise he might have smelt it.
824
Mr Bollands has Mr Vernon coming back into the Control Room about
ten minutes after the pump alarm had annunciated. This timing must be
approximately right considering what must have passed since the alarm. At the
point of his return to the Control Room Mr Vernon seems to have supposed that
the trouble relating to Pump B stemmed from a problem with the lube oil system.
Mr Bollands in relating what then occurred said “He wanted to get the other
pump going, he wanted to take it back off maintenance.” If at that point
Mr Vernon had tried to contact any of his superiors over the radio the likelihood
is that his message would have been heard by others. The practice for operators
was to keep their radios on all the time. Further if Mr Vernon had contacted his
superiors by telephone from the Control Room Mr Bollands would have heard
this. Mr Vernon’s intimation to Mr Bollands that he wanted to take Pump A
back from Maintenance caused the latter no concern which of course is consistent
with Mr Bollands having no knowledge of the position relating to PSV 504.
When Mr Clark was contacted about the retrieval of Pump A for production
according to Mr Bollands he was “happy” about that suggestion. After leaving
the Control Room (possibly having met Clark and had a discussion with him) Mr
Vernon returned directly to the 68-foot level. Between Mr Vernon’s return to the
Control Room and the first gas alarm he would have had enough time to jag the
pump especially when it is considered that at best timings must be rather
approximate. Of course whether any jagging operation took a few seconds or 30
seconds and whether it comprised one operation of the push/pull button or more
would depend on how it was done. Certainly it looks as if about 15 minutes
lapsed between Mr Clark receiving his Tannoy call from Mr Vernon and the
explosion. Thus even allowing for a measure of flexibility in the timing of
825
incidents like the first alarm there was space for Mr Vernon to have jagged the
pump. Indeed if the jagging at that point consisted of two consecutive short
operations close to one another in time there would even have been time for this.
The pursuers of course pitch their main case at there having been two quite
separate jagging procedures. This must be the minimum they require since there
were seemingly two distinct leaks causing two separates alarm responses. Indeed
it is the staggered operation involved in the re-pressurisation of the pump that
they say justifies their view that a leak during jagging caused the accident.
However it is more probable, I think, that if Mr Vernon (or for that matter Mr
Richard) jagged the pump he must have completed the first stage of jagging (the
one causing the first low level alarm) before Mr Grieve came on the scene.
There would probably not have been enough time left after Mr Grieve arrived
and certainly Mr Richard went away soon after Mr Grieve’s arrival. Moreover
had there been two distinct jagging operations when Mr Grieve had been present
then the possibility that he would have noticed this happening must increase
substantially. On the other hand if Mr Vernon or Mr Richard sought to re-
pressurise the pump before Mr Grieve arrived on the scene we can only surmise
just how the operation would have been carried out since there were no eye-
witnesses. Different operators seem to have employed their personal and
individual jagging techniques. Thus it is perfectly possible that if there was an
attempt to re-pressurise the pump, at a point in time before the first alarm and
before Mr Grieve arrived, two separate lots of hydrocarbon were admitted into
the pump at that stage. It is equally possible on the basis of the evidence of Dr
Davies that the first entry of material if it caused a leak would not have extruded
sufficient hydrocarbon to have set-off an alarm. When the valve was opened
826
again then the material that emerged may have been heavier gas and triggered an
alarm. With the pump leaking Mr Vernon may have decided some minutes later
that the pump was still not fully pressurised and at that stage introduced the gas
that caused the second stage alarms. The pump had a pressure gauge so that the
person jagging the pump could see if the pump had been adequately pressurised.
If Mr Richard had been the person who first jagged the pump Mr Vernon may
have looked at the gauge to see if the pump was satisfactorily re-pressurised.
Given that within limits jagging procedures vary it would be difficult to be
certain as to just what the jagging sequence was and the only indication that gives
positive information is the pattern of the alarms. If the pump was jagged against
some minutes after the first insertion of hydrocarbon to the pump this may
explain why there was a delay between the first escape that registered and the
second.
The tags appear to have been left with Mr Clark after he had signed them.
This would follow from Mr Clark’s own account of events since he has
Mr Vernon out of the Control Room before he arrived there. Thus as far as
Mr Vernon was concerned Mr Clark had the tags and was arranging for the
electricians to de-isolate the pump. Mr Clark’s instructions had never been
cancelled. This all leads to the important conclusion that the arrangements to re-
start Pump A were going ahead and indeed were in train when the explosion
occurred. It should also be noticed that a decision to re-introduce Pump A did
not mean abandonment of plans to start Pump B as soon as possible. Mr Clark in
his account of his telephone conversation with Mr Vernon (direct or indirect)
said that the objective of re-introducing Pump A was to secure more time to work
on Pump B. As Mr Clark added there was obviously a problem with Pump B so
827
we needed more time to investigate it. Thus at least the objective would not be
to spend time with Pump B if this would be at the expense of getting Pump A
started.
Mr Clark seemed to think that he had telephoned Mr Savage from his
own office after his communication with Mr Vernon but before he went to the
Control Room. Since Mr Clark arrived at the Control Room before the first gas
alarm his contact with Mr Savage must have been some minutes before that first
alarm. If Mr Clark is right and Mr Vernon was away from the Control Room
when he arrived there then Mr Vernon may well have left the Control Room as
soon as he had done all he had to do there by making his arrangement with Mr
Clark. This too could demonstrate that there was a space of time between Mr
Vernon’s return to the Control Room and the first gas alarm.
It can be observed that the electrical switchgear for Pump A was at the
107-foot level in the Utilities Mode. Of course Mr Vernon may not have realised
how long it would take Mr Clark to have the pump electrically de-isolated so that
he may have had the intention to press on with the de-isolation of the pump as
quickly as he could reasonably do so.
The evidence of Mr Grieve as to what was happening on the 68-foot level
at the time of the explosion is particularly important because he was one of the
two survivors in that position (the other being Mr Young). Mr Grieve says that
when he arrived at the 68-foot level it was rather noisy. This comment is not
surprising because there is a lot of noise in the working areas of a platform and
this is why the men working there often wear ear protectors. I mention this
because it could have a bearing on a suggestion that perhaps Mr Vernon had any
kind of elaborate conversation with Mr Richard. To get to his worksite
828
Mr Grieve had ducked under the JT Flashdrum. Mr Grieve walked past the
control panel JCP57 up towards Pump B. He noted that the level in the
Flashdrum was relatively high and that Pump B was not working. However the
higher level was still well short of the danger level. He also noted that the GOVs
for both pumps were closed. Of course Mr Grieve may not have known of the
intention to de-isolate Pump A and he may well have assumed that the focus was
on Pump B which he knew had caused trouble. As he approached the pump he
became aware of Vernon and Richard at the west side of Pump B and at the foot
of the GOV on the south side. Now Mr Grieve according to his own recollection
was at the 68-foot level for about two or three minutes before the explosion. He
does not claim that Mr Vernon and Mr Richard were doing anything in particular
when he first caught sight of them. If the explosions were caused by two distinct
jagging operations and there was as witnesses describe a few minutes between
the first gas alarm and the second flurry of alarms then one would expect a
similar time difference between the two jagging operations.
By signals from Mr Vernon (which Mr Grieve describes as shouting or
sign language) it was indicated to him that another attempt would be made to
start Pump B. He cannot remember if he personally reset the GOVs but they
seem to have been set and another attempt made to restart the pump. Mr Grieve
makes an important concession for when asked what the others were doing at the
time he says that it is a difficult thing to say if you see people going about
functions that are done routinely and he states “I can’t say I was aware of exactly
what was being done at the time”. Given that Mr Grieve had just arrived at the
scene I cannot say that this is surprising. However he does say that he had the
impression that the others were in the vicinity of Pump B and a decision was
829
made to have as he puts it “another go at starting B Pump as GOVs for B Pump
were re-latched at that period”. He cannot say whether it was Vernon or Richard
who reset the GOVs for the pump. However that may suggest that the work on
the GOVs was done when Mr Richard was still there for not long after
Mr Grieve’s arrival Mr Richard departed. This would coincide with the message
he received from Mr Bollands that a gas alarm relating to Module C had gone
off. It is perhaps significant that the message received by Mr Richard which
presumably Mr Vernon also heard over the radio that an alarm had gone off at
the east end of Module C did not appear to have concerned Mr Vernon as might
have been expected if he knew that he was doing something irregular affecting
that area. Mr Grieve accepted that he personally had carried out some function at
the Control Panel and this would have taken him to a position about half way
between the two pumps. Indeed he recollects that he pressed the button for
Pump B, watched the motor turn, stopped the motor when he took his hand off
the button, and then proceeded to the torque converter to make sure that it was at
manual with the speed wound off it. He claims that he never actually got a
chance to check the speed controller before the accident. When he was asked if
he was aware of anyone else at that stage he said that he remembers seeing
Mr Richard called away. This was the last time that anyone saw Mr Richard
because he did not re-emerge after the accident. The interesting point is that in
response to the last inquiry he makes no claim to have noticed what Mr Vernon
was doing.
In the course of the duties I have referred to Mr Grieve also had to give
some attention to the local pump panel. This comprised a cabinet with a door
and this door had to be opened to gain access to the button inside. There were
830
also some lights within the panel that could if circumstances were appropriate
indicate alarms. Indeed he noted that the alarm for the JT Flash Drum was
indicating. The point of giving these details is that there was the potential for Mr
Grieve having his attention occupied as he performed some of his duties. The
defenders argue that it was never shown that Mr Grieve knew that the injection
pump A was not on standby. Indeed he himself claims that he did not know the
state of the pumps and I have no reason to disbelieve him about this. However I
am not sure to what extent it matters. Indeed if the case was that Mr Grieve was
not aware that Pump A was de-pressurised this may have been a reason why he
would not readily have supposed that Mr Vernon was jagging the pump. In any
event whatever Mr Vernon was doing Mr Grieve seems to have had no precise
knowledge of this.
The defenders argue that whatever Mr Vernon had been doing when
Mr Grieve arrived he was not at the GOV push/pull button. A little later he saw
Mr Vernon and Mr Richard at the west side of the Condensate Injection Pump B
towards the south end. He did not know what they were doing. Of course Mr
Vernon had already indicated that he considered the lube oil system as being the
source of the trouble with Pump B and it is possible that when Mr Grieve first
saw him he was inspecting it. He also indicated that when he arrived Mr Vernon
signalled or called out to him that they would go for a run on the B pump. Mr
Grieve was not sure if he was the person who had reset the pump. The last Mr
Grieve saw of Mr Vernon before the accident Mr Vernon was between the GOVs
on the pumps. He did not say whether he was coming or going. Thus he had no
idea what he was doing in that area. For that matter Mr Grieve does not specify
what he himself was doing at that point of time. He thinks he may have been
831
walking round the local panel. Of course it is consistent with this evidence that
Mr Vernon was not proceeding to jag Pump A but was returning from having
done so.
I must add that in relation to what was happening at the 68-foot level and
elsewhere just before the accident the very short timescales remembered by
witnesses cannot be taken too literally.
If Mr Richard had arrived in Module C after an initial jagging and after
the first gas alarm had annunciated then by the time he arrived there may not
have been any obvious escape of gas. Indeed two quite separate escapes of gas
dispersing quite quickly and with an interval between them may explain why he
sent no immediate signal to Mr Vernon or Mr Bollands that there was a serious
gas escape. If there had been a steady leak of gas filling a substantial part of
Module C Mr Richard might have been expected to pass an emergency message
on to Mr Vernon or Mr Bollands at once. On the other hand a leak from the
PSV, if there was one, would have decayed and much of the initial leak of gas
would have been transported eastwards along the module. However if the
explosion was caused by a second jagging process then this would have occurred
so close to the explosion that Mr Richard may not have had time to contact the
Control Room particularly since by that time Mr Bollands was heavily occupied
with a flurry of alarms. On the other hand Mr Grieve said that Mr Richard left
the 68-foot level about a minute before the explosion.
Mr Grieve last saw Mr Richard going up the stairs to the south side of the
pumps (which leads to C Module.) This happened after Mr Richard had received
a call which Mr Grieve says he did not listen to. Apparently radio messages are
directed towards particular participants and Mr Grieve said that if the message
832
was not for you one might not listen “if you were busy”. He stated that you
would carry on with what you were doing and not listen to the message. This
may suggest that Mr Grieve was occupied when Mr Richard was called away.
The message that Mr Grieve would have received was that an alarm had gone off
in zone 3 of Module C so that it is not difficult to suppose that he was proceeding
to the east end on that Module. According to Mr Grieve the explosion was about
one minute after the last time he saw Mr Richard.
As far as Mr Young is concerned he cannot say much about what
preceded the explosion. He came down the stairs to the 68-foot level after
Mr Richard had left there. He had only taken a step or two after coming off the
stairway when the explosion occurred. It is perhaps significant that Mr Young
did not encounter Mr Richard on the stairway since this adds support to the view
that there was a material interval between Mr Richard leaving the 68-foot level
and the explosion. He thought that when he arrived Mr Vernon and Mr Grieve
walked towards him to speak to him but the explosion occurred before they got
together. Mr Young heard a strange sound before the explosion. Mr Grieve does
say that as he was attempting to start Pump B he was watching the motor which
may suggest a degree of pre-occupation. When the motor would not start
Mr Grieve went round to the speed controller and it was then when the explosion
occurred.
Mr Young went to the 68-foot level after receiving a radio message to go
there. This is consistent with Mr Clark’s evidence that Instrument Technicians
would be called to assist in starting a tripped pump that was resistant to
restarting. It is perhaps significant that Mr Young was at the west side of the
platform shortly before the accident because an idea that was canvassed was that
833
the blue flash noted by Captain Clegg may have been caused by a trail of escaped
gas along the west face of the platform. If there was such a trail it would appear
that Mr Young did not notice it. When Mr Young arrived at the 68-foot level
Mr Vernon and Mr Grieve were near the condensate injection pumps but they
apparently moved towards him perhaps to get into a better position to talk to him
above the noise. However before he got a chance to speak to them there was a
sound like a quick escape of steam and this ended in a dull thud. Dr Mitcheson
ascribed this noise to the gas moving at the explosion.
The defenders make the evidence of Mr Grieve one of the lynch pins of
this aspect of their case. Their argument put simply is that Mr Grieve’s evidence
makes no mention of the jagging of the pipe by Mr Vernon. This evidence they
say was not the subject of cross-examination so that the pursuers must be taken
not to have challenged it. The defenders therefore claim that there is
uncontroverted evidence of the fact that Mr Vernon did not jag Pump A during
the time Mr Grieve was at the 68-foot level which was the space of about
three minutes before the accident. If the facts were that Mr Grieve’s evidence
positively excluded the possibility that Mr Vernon jagged the pump during the
period his evidence covers then clearly this would make the pursuers’ cases
difficult. I may say that I have no trouble in concluding that Mr Grieve was an
honest witness trying faithfully to remember what he had observed. I doubt
whether the pursuers would disagree with that or otherwise they would no doubt
have cross-examined Mr Grieve. I think the pursuers did not challenge
Mr Grieve because they accepted that all he describes is precisely how he
remembers the situation and he did accept the possibility of imprecision in his
recollection. Mr Grieve did not give evidence that Mr Vernon did not jag the
834
pump. What he did was to give evidence that he did not notice Mr Vernon
jagging the pump and it was this that the pursuers must be deemed to have
accepted. In fact going beyond that I think the pursuers must be taken to have
accepted that what Mr Grieve is accurate so far as it goes. If this is so the
pursuers had no need to challenge Mr Grieve because they accept what he says.
The question of course is how far does Mr Grieve’s evidence actually go.
Mr Grieve states what he saw and that certainly gives little support to the
suggestion that while he was present Mr Vernon jagged Pump A. Of course the
question is whether what Mr Grieve says excludes the jagging of the pump. If
Mr Grieve is effectively saying no jagging of the pump took place while he was
there then that evidence if unchallenged would as the defenders contend be bad
for the pursuers. However he in no way goes as far as that. All he is saying is
that he personally did not see any jagging. However that must be taken against
the whole context of his presence at the 68-foot level. The positions he gives as
relating to Mr Vernon only cover discrete points of time in relation to what
Mr Grieve was doing. Moreover he accepts that he was not concentrating on just
what Mr Vernon was doing apart from taking a general interest in starting
Pump B. Whereas these positions do not support specifically that Mr Vernon
was jagging the pump they do not negate that suggestion either. After all we are
discussing a procedure that would have involved Mr Vernon in moving a few
yards and taking perhaps 30 seconds or so. Mr Grieve was not standing watching
most of the time but rather was engaged in his own work. As he himself
observes he may well not have registered the routine work of his colleagues if
engaged in his own tasks. When he arrived at the 68-foot level his thoughts were
not on jagging Pump A since he thought that pump was pressured up and on
835
standby. Thus he would scarcely have expected Mr Vernon to be jagging the
pump and could easily have missed that if it occurred. If the only evidence that
Mr Vernon might have been jagging the pump was the eye witness evidence of
Mr Grieve then I could not possibly have concluded that he was thus acting.
However Mr Grieve’s evidence does not stand alone. There is good evidence
that Mr Vernon went to the 68-foot level with the express intention of starting
Pump A. There is other expert evidence that the jagging of the pump would be
consistent with the circumstances of the explosion. I do not see the evidence of
Mr Grieve as defeating the inferences about jagging that might be drawn from
other facts and circumstances. It is true that if the pursuers had seen fit to ask
Mr Grieve if he could possibly have missed what Mr Vernon was doing they may
have unearthed strong support for their hypothesis or conversely unearthed
additional information which would have defeated it altogether. However the
same could be said for the defenders. I can only decide the case on the evidence
actually put before the court and the inferences that can be drawn from that
evidence as it stands.
7.4. Noise
The pursuers have pleaded a case that the noise heard by personnel
shortly before the accident was consistent with the hypothesis that the accident
was caused by a leak from PSV 504. However this case was developed
somewhat half-heartedly compared with the effort that went into other aspects of
the case. For example I did not have the benefit of expert evidence about
acoustics. However there was some relevant evidence. Nevertheless it must be
observed that there was evidence from Dr Mitcheson that locating the source of
836
noise is a very subjective matter (as anyone who has tried to react to a foghorn
will know).
Dr Richardson claimed that he had been present at a release when gas was
leaked through holes and he describes the resultant noise as a very high pitched
screech. This would tail off as the pressure decreased.
Witnesses who were present in the Instrument Workshop or the Tea-room
heard a noise before they were conscious of an explosion. Other witnesses heard
nothing significant but then they were often further away from Module C where
the explosion is alleged to have taken place or in noisier areas of the platform.
At least out on the Modules ear protectors are often worn.
Mr Young heard a rushing noise just before he was hit by a blast of gas
but as I have said Dr Mitcheson thought that the likeliest cause of this was fast
moving gas propelled by the explosion. On the other hand Mr Grieve heard a
noise above his head sufficiently loud in the noisy atmosphere where he was
working to cause him to fall on his knees (and he was wearing ear muffs).
There was some evidence about noise from Mr MacGregor who was a
Mechanical Technician and was in the Mechanical Workshop Tea-room when the
accident occurred. Mr MacGregor describes how he was sitting talking when all
of a sudden there was a loud noise like a banshee screaming. This description
requires a certain amount of imagination since the phenomenon he mentions is
not one with which many of us are directly familiar. In any event the noise was
said to have lasted about half a minute. The noise disturbed the company he was
with. He thought that it must be due to trouble with the air start of the west
crane. It is interesting that he associated it with pressurised gas such as the air in
a crane. This does not appear to have been the same kind of noise that Mr Young
837
described because Mr MacGregor says that conversation stopped and then started
up again just before the explosion. A minute or two afterwards the explosion
occurred. There was blackens and the lights and fittings fell down.
Mr Thompson was a Maintenance Rigger and he was in the same location
as Mr MacGregor. He also speaks of a loud screeching noise. He was surprised
by the volume of this noise. The explanation for the noise that was considered
by this witness was that someone had got stuck in machinery so obviously we are
dealing with a very unpleasant sound. He thought that the noise had lasted for
about 10 seconds. He also thought that the noise was ten times louder than any
sound that may have come from the air of the crane could be. Twenty or
thirty seconds or so after the noise there was an explosion. Again the explosion
was accompanied by physical phenomena like the collapse of the ceiling. It
seems clear from the evidence that the explosion was accompanied by a fair
degree of violent vibration and some of the damage after the explosion may be
attributable to this. Mr Thompson accepted that the sound he heard could have
been caused by steel ripping apart.
The witness Mr Cassidy was an Instrument Technician who was in the
Instrument Workshop when the explosion occurred. He describes how before the
explosion he heard a very, very, high pitched noise like metal grinding at high
speed. It was a frightening noise such as he had never before heard in his life.
The noise lasted a short time perhaps ten seconds. As soon as the noise stopped
the workshop began to shake and he was knocked off his feet. Apparently when
Mr Cassidy gave evidence at the Cullen Inquiry he said that the noise he had
heard had lasted some minutes. This confusion in his evidence may not matter.
In these proofs a lot of time had passed since the Cullen Inquiry and in any event
838
in the circumstances experienced by these witnesses I would not take timings too
literally. On the other hand the timings put forward by Mr MacGregor and
Mr Cassidy were not challenged and were fairly consistent one with the other.
Mr Standen in his tests had found that escapes of gas through a leak could
produce a high pitched noise.
The evidence given by these witnesses seems in general to negative any
suggestion that the main cause of the explosion was an escape of hydrocarbon
some minutes before the explosion (rather than seconds). Moreover the location
of the witnesses might suggest that the likelier source of the noise was Module C
and not Module B which was further away. Indeed the divers who had been
working closer to Module B do not speak to having heard a similar noise. I do
not think it can be doubted that the noise heard by the witnesses I have been
discussing was related to the explosion and that gas escaping through a leak can
in certain circumstances cause a noise.
7.6.Conclusions about cause of accident
7.6.1. Outline of the Pursuers’ arguments
The pursuers, as might be expected, were anxious to convince me that the
accident had been caused by the explosion of a heavy gas which leaked out of
PSV 504. They contended that the explosion occurred at the east end of
Module C and that is consistent with the fact that the alarms which annunciated
related to that end of the Module. Moreover the escape of gas according to the
pursuers can be related to contemporaneous activities at the 68-foot level.
Mr Vernon not only intimated to Mr Bollands an intention to start Condensate
839
Injection Pump A but he had the opportunity to begin the procedures needed to
secure that objective. Counsel argued that it would be highly co-incidental for
gas to have accumulated at the east end of Module C and yet not be the cause of
the explosion. It would be a further co-incidence that the activity of introducing
a heavier than air hydrocarbon at the pump was unrelated to the accumulation of
gas at the east end of the module at the same point of time. The pattern of the
alarms support a limited release of gas followed some short time later by a
further release. It was said that the evidence showed that the blind flange would
have leaked if it were insecure and the amount of gas released would depend on
the size of the leak and the conditions within the pump. Because the size of leak
would be related to the extent of the re-pressurising of the pump one could have
a small release succeeded by a much larger release. The general picture of the
leak and its potential could be arrived at without reference to the computer work
carried out by Dr Bakke or Dr Richardson and also without the detailed wind
tunnel tests carried out by Dr Davies. The pursuers’ case is that the firewalls
were breached and the breaches established were totally consistent with the site
and extent of the explosion which the pursuers seek to demonstrate. Moreover it
was said that if there was an explosion which breached the firewall then it could
be readily inferred that fragments of the wall would be propelled under some
force and that this phenomenon could itself damage the condensate line within
Module B and cause it to leak. It was, so it was claimed, established that the
large fire in Module B at an early stage of the accident was fuelled by condensate
and this fact goes to show that the condensate line was damaged by the initial
explosion. The pursuers were at pains to point out that they were not depending
on any individual circumstance but rather on the way the circumstances fitted
840
into one another and combined. It was claimed that the hypothesis that the
explosion happened in Module B was in no way supported by the evidence. The
fact that there were two flurries of alarms goes to support the inference that the
escapes of gas occurred during a multi-stage process such a jagging. Dr Davies it
was suggested confirmed that for only one gas alarm to have triggered at the first
stage any appropriate release of gas would have to have formed a shrunken
cloud. One release of gas during jagging if it encountered an insecure blind
flange at PSV 504 would generate a gas cloud downwind of the valve. It was
said that Dr Davies should be read as saying that depending on the size of any
leak the time taken for the cloud of gas to form and trigger alarms would range
from 15 to 40 seconds. Even without the modelling tests it was clear on the
qualitative evidence that it would take only a small lapse of time for any escape
from the blind flange to arrive at the point where alarms would be triggered. If
the initial release was a limited release then by the time Mr Richard arrived at
Module C to investigate it would have dissipated sufficiently to make the leak
hard to identify. When Mr Vernon realised that Mr Richard had been called
away to investigate a gas alarm the fact that he proceeded with his work suggests,
so it was contended, that he did not connect an alarm in Module C with what he
was doing. He would have made the connection more readily if he had been
aware at that point that PSV 504 was missing. Indeed this was one of the factors
I accepted as being relevant to forming a view about the state of knowledge of
Mr Vernon. It was said that after Mr Richard went upstairs to investigate Mr
Vernon would have carried on with his work and jagged a second time. A
consequential leak would explain the second flurry of alarms. The greater the
spread of the gas then the more likely it would be that not one, but a flurry, of
841
alarms would go off. Although there were a number of detectors perhaps
designed primarily to detect gas within the compressors they could also detect
gas outside the compressor compartments. The experts estimated that the sort of
cloud that emanated from a leak at the blind flange might occupy about one tenth
of the volume of the Module and would be driven by the airflow to the east end.
Dr Bakke considered that the kind of gas cloud that is being postulated could if it
exploded develop an overpressure of between about 0.2 and 0.7 bar and that
these pressures would endure for about 100 milliseconds or more. This has a
bearing on the response of the C/D firewall to any explosion because being a
stiffer wall than the B/C wall it would have a shorter natural period and thus
would respond in a static rather than a dynamic way. The evidence was that the
overpressures that the postulated cloud could generate upon explosion would
have been more than enough to cause penetration of the C/D wall. It was
submitted that the evidence shows quite clearly that both the B/C and C/D
firewalls failed so that the latter wall being stronger if it failed it is not difficult to
conclude that there would be more than enough overpressure to collapse the other
wall. Moreover the C/D firewall was stronger than the A/B firewall so that if
there had been in Module B an explosion sufficient to penetrate the C/D wall
then certainly one would have expected the A/B wall also to have been
penetrated. It was pointed out that the evidence was that the A/B firewall
remained intact. Dr Richards calculated that with a hole of a certain size and an
upstream pressure of 46 bar then a release rate of 180 kilograms per minute
would be generated. Dr Davies calculated that a release of the order of 150
kilograms per minute could after being sustained for 30 seconds create a
flammable cloud of about 45 kilograms. Dr Mitcheson and Mr Cubbage thought
842
that that size of cloud was the size likely to have caused the particular explosion
which occurred. I was asked to accept Dr Palmer’s evidence that with such an
explosion the pressure pulse generated on the B/C firewall would have been of
sufficient energy to cause a projectile capable of damaging the condensate line.
Pursuers’ Senior Counsel saw the expert evidence of the pursuers to have a
general consistency. It was contended that the pursuers can comfortably
establish their hypothesis even without the evidence of Dr Palmer.
Dr Drysdale thought that the inventory of fuel oil that might have escaped
from the small bore piping in the vicinity of the fire would not have caused a
sufficient pool of fuel to have sustained the fire which later developed. He
postulated that the most likely explanation for a continuing oil fire in excess of
the available inventory was backflow from the MOL via ESV 208 it having
failed to close. The ESV not only had the electrical power which normally drove
it but it had a back-up nitrogen system. However the nitrogen was transmitted
through a valve from the pneumatic connection and it was argued that these
would be vulnerable to fragments propelled by an explosion. The pursuers urged
me to accept Dr Drysdale’s hypothesis about the fuel supply. It should be noted
that quite soon after the explosion men located near the Divers’ Skid noted oil
running freely down the MOL. In relation to the explosion causing damage to
small bore pipe work carrying oil it should be noted that at the time of the
accident the prover loop was missing and since the prover loop normally sat on
top of small bore pipework it would have provided some protection to the
pipework which would at the time of the accident not have been in place.
If an explosive cloud leaked from the blind flange at the suction side of
the site of PSV 504 then this, it was contended, inevitably reflected adversely on
843
the care taken by the fitter, Sutton who had fitted the blind flange. A flange
which has been properly fitted and tightened by the prescribed procedures should
not leak hydrocarbon. Since the blind flange in question did leak the inescapable
inference is that Mr Sutton failed to take reasonable care when he fitted it.
7.5.2. Outline of the Defenders’ Submissions
The thrust of the defenders’ attack on the pursuers’ case was that the
pursuers had failed to prove the cause of the accident. The pursuers could not
recover under the indemnities unless the cause of the accident were established.
Without the cause of the accident being demonstrated the pursuers could not
prove that they were under any legal obligation to settle with the victims and
their families. It was not enough that the pursuers might claim that a particular
suggested cause of the accident was a possibility. The circumstances of the
accident had to be proved on a balance of probability. The defenders urged upon
me the various rules and principles which I have set out above and which
circumscribe the law of evidence.
According to the defenders because all the main witnesses did not survive
the accident, and furthermore all the platform and its equipment rest
irrecoverable at the bottom of the ocean, the precise cause of the Piper Alpha
tragedy will never be known. At best the pursuers case is highly circumstantial.
However if a necessary link in the circumstantial chain is shown to be untenable
then the whole hypothesis derived from the circumstantial evidence must
collapse. The pursuers seek to build up their case by relying upon coincidence
based mainly on the fact that Mr Vernon expresses an intention to re-pressurise
Condensate Injection Pump A. However there were numerous other hypotheses
844
derived from coincidence which point to quite different results. Thus several
days before the accident the platform had changed from Phase II to Phase I
operation. This meant that the existing equipment required to cope with
considerably enhanced operational pressures and the ageing equipment may not
have been able to cope with this. There had been trouble with one of the
Condensate Injection Pumps following upon the transfer to Phase I. It was
curious that when the explosion occurred all three Centrifugal Compressors had
tripped. The Prover Loop had been displaced at the time of the accident and this
could have caused a hydrocarbon leak in Module B. On the day of the accident
work had been proceeding in the area of the Prover Loop. The safety door
between Module B and Module C may have been left open. The Flotta Terminal
had registered a breakdown in production before the alarms and this too was
more than co-incidence. The defenders made much of the blue flash reported by
Captain Clegg and of the embarrassment Dr Mitcheson experienced when he
dealt with this. The expert evidence, it was said, agreed that the blue flash
described by Captain Clegg could not have been caused by an explosion in
Module C. The pursuers had accepted Captain Clegg’s account of events which
meant that they could not continue to maintain their circumstantial case. When
Mr Grieve had approached the mouth of Module C after the accident he had not
seen anything indicating a breach in the B/C firewall.
The defenders maintained that neither Dr Mitcheson nor Mr Cubbage had
anything like the experience of hydrocarbon explosions enjoyed by Dr Bakke.
Likewise Dr Drysdale was an expert on fire affecting solids and did not have the
relevant experience of Professor Magnussen. The latter had suggested that both
the original fire and the fireball were consistent with a pool fire in Module B and
845
his evidence cannot just be discounted. No one had explained in satisfactory
terms why if the fireball had been caused by the combustion of condensate
released from the 4 inch line there had been a gap of 15 seconds or so between
the explosion and the manifestation of the fireball.
The pursuers’ evidence about the alleged destruction of the B/C firewall
was not satisfactory for the reasons indicated in the evidence of Professor Reid
and Professor Stollery. At best for the pursuers a strong shadow of doubt had
been cast over that evidence. In respect of their static analyses of the failure
point of the firewall Professor Fenner and Dr Palmer had contradicted each other.
Nevertheless Dr Bakke in his simulation had been asked to incorporate
Dr Palmer’s failure value and if this was the wrong value Dr Bakke’s results
were suspect. On the other hand Dr Palmer had relied on Dr Bakke’s pressure
pulse in his own dynamic analysis so that the conclusions of these two experts
are critically inter-related. Important factors including membrane stress, strain
hardening, kinematic impossibility, collapse mechanisms and theory and flexural
rigidity had not been properly taken into account by Dr Palmer and therefore in
any event his conclusions cannot be accepted as valuable. Dr Bakke in his
general evidence had expressed doubt as to whether the overpressure created by
an explosion of 45 kilograms or so of hydrocarbon would have been sufficient to
destroy the effectiveness of the firewall. Moreover he had noted with lighter
structures than the partitions these had only moved away about 10 centimetres at
the end of the explosive pressure pulse and this does not consist with the sort of
movement in the firewall that the pursuers would require to create projectiles
with sufficient energy to damage the 4-inch condensate line in Module B. In any
846
event it is not possible to conduct an exercise such as ventured by Dr Palmer
without a computer analysis.
The evidence of Professor Reid and Professor Stollery had to be
considered in relation to projectiles and this evidence at the very least casts doubt
on Dr Palmer’s calculations. He had not taken sufficient account of shock tube
theory nor had he taken the support conditions of the condensate line into
account.
The defenders did not accept that the A/B firewall had not been punctured
by the explosion. If the C/D firewall had been punctured this could result from
an explosion in Module B which was amplified by the process known as pressure
piling. The C/D firewall was not necessarily seriously damaged by the
explosion. As Professor Magnussen had explained the penetration of flame and
smoke to the north face of the platform could be due to flame emanating in
Module B being blown over the roof of the Accommodation Modules.
The defenders contended that the evidence of Dr Davies and
Dr Richardson in fact destroyed the pursuers’ hypothesis. The important
consideration was that any gas which might have escaped from the PSV blind
flange would not have been heavier than air as Dr Davies’ modelling assumes but
rather would have been neutrally buoyant. This is because of the flashing off of
lighter ends when the hydrocarbon stream first enters the empty pump and also
the accumulation of compressed air that has to be expelled from the relief line
before liquid condensate can escape. In fact given the fact that the alleged first
jagging would have produced a neutrally buoyant escape the modelling of
Dr Davies shows that such an escape could simply not occur without a detector in
the C2 zone triggering an alarm. This did not happen. Moreover Dr Davies
847
acknowledged that the presence of scaffolding beneath the blind flange would
have the effect of dispersing any escaped gas and this would prevent the
formation of a compressed low lying cloud. such as was required to escape
triggering the C 2 alarm. The evidence of Dr Bruun also casts doubt on the
reliability of the modelling methods of Dr Davies.
The defenders also placed considerable stress on the fact that Mr Grieve
was the only witness who could have seen Mr Vernon or Mr Richard jagging the
injection pump but his uncontroverted evidence was to the effect that when he
was present at the pump just before the accident he did not see this happen.
The defenders submitted that there was no evidence to suggest that
Mr Sutton had not properly tightened the bolts on the blind flange. He was an
experienced valve fitter. The bolt tightening operation was straightforward and
there was no reason why he should have departed from standard procedures.
Certainly none of the eyewitnesses suggested anything from which it could be
supposed that he did so. Moreover he was not at fault in relation to any escape of
gas due to a loose fitting flange. The combination of events that led to
Mr Vernon attempting to start a pump when the blind flange was missing was
totally unforeseeable. Moreover Mr Vernon’s intervention in the matter broke
the chain of causation.
If Mr Vernon did cause the accident by attempting to re-pressurise the
pump when the PSV was missing then his actions were reckless and amounted to
wilful misconduct on his part. In any event the Company had been guilty of
wilful misconduct in tolerating irregularities in the permit to work system and in
failing to monitor and audit this and the handover system.
848
In a case of this dimension both the pursuers and the defenders developed
many issues in their submissions and those I have outlined are only the more
salient of these.
7.5.3. The Cause of the Accident
The Piper Alpha disaster is one of the worst tragedies, if not the worst,
ever to have been suffered by the Oil Production Industry. To establish the cause
of this accident is of critical importance to the parties in the cases before me but
because of the extent of the catastrophe it is also of considerable interest to the
industry and the public. Of course I have to make a decision about the matter
within the limits of the evidence the parties have led before me and within the
technical confines of the rules of Procedure and Evidence. However the issues
surrounding the cause of the incident were explored before me in considerable
depth (and also I may say at considerable length).
The defenders sought to persuade me that the elucidation of what caused
the accident was a matter of such complexity and difficulty that no firm
conclusion as to what happened could properly, or indeed safely, be pronounced.
There is no doubt that such evidence about the accident as is available is
considerably less unarguably decisive than I should have preferred. Many of the
platform personnel who had direct involvement in the events alleged to have
caused the accident (or the circumstance relevant to their determination) did not
survive the accident. The result is that I am left to decide many mysteries which
those most directly involved could have unravelled with likely authority had they
been able to give evidence. The same position arises in relation to such parts of
the structure and its equipment as could have cast light on what occurred. The
849
platform and the equipment on it are, as far as the parties were concerned,
irrecoverably lodged at the bottom of the North Sea.
A particularly difficult situation arises in respect of OPCAL’s Lead
Production Operator, Mr Vernon, and the Valve Fitter, Mr Sutton, who was
employed by Messrs Score. Both these men tragically died in the accident yet it
is said that their fault was the cause of this dreadful event. In fact the pursuers’
case depends on this being established. Obviously it is a matter of great concern
to be asked to blame an accident as serious as the present one on two workmen
who do not even have the opportunity to explain themselves and give their
version of what happened. I am well conscious that the situation I have just
mentioned calls for particular care and that the employees in question cannot
have blame for the accident attributed to them unless it is clear that this is
justified. The core argument of the defence is that such evidence as I may find
acceptable is so flimsy, the inferences needed to support the pursuers’ case so
uncertain and complex, and the possible causes of the accident so multifarious
that the only reasonable course available to me is to hold that the cause of the
accident simply cannot be proved and indeed may never be proved.
To extract from the huge array of available evidence a convincing
explanation for the accident is indeed a formidable task and it therefore would be
tempting to follow the course urged upon me and declare that it is just too
difficult to arrive at a firm view. It also has to be admitted that no single feature
of the evidence points so strongly in one direction that the solution of the case
could be found in it. However as so often is the case in such matters individual
pieces of evidence themselves inconclusive can when viewed together paint such
a clear picture that only one conclusion is possible.
850
In the cases before me there is factual evidence spoken to by witnesses
and opinion evidence explained and spoken to by a number of highly qualified
experts. The evidence I found most important and useful was that of the facts
and circumstances spoken to by witnesses with direct knowledge of them. Much
of the technical evidence spoken to by experts was somewhat speculative and
often disputed. Had I had only the technical evidence available I should not have
been able to arrive at any conclusions. However the technical evidence can itself
acquire added significance if it fits in well with the facts established by the direct
evidence of lay witnesses.
The most important and incontrovertible fact affecting this aspect of the
cases is that some minutes before that explosion that triggered-off the accident
the Lead Production Operator Mr Vernon signalled his intention to attempt to
start up Condensate Injection Pump A. At the time the pump had been
withdrawn from Production for a planned maintenance procedure and moreover
the relief line from the pump was interrupted because PSV 504 been removed for
calibration. The end of the relief line which had thus been opened was
supposedly sealed by a blind flange that had been fitted by Score’s employee
Mr Terrence Sutton. When he indicated that he was about to re-pressurise the
pump Mr Vernon was in immediate control of the production processes.
Moreover not only did he intimate an intention to re-pressurise the pump but
there is little doubt that he took at least certain practical measures to execute the
operation he intended such as having isolation tags signed-off and arranging to
summon electricians to de-isolate the Pump. Before he could start the pump the
empty pump chamber had to be re-pressurised by the admission of the main flow
of condensate and this operation would have been carried out in a number of
851
stages by opening the main suction GOV leading to the pump by a series of
controlled operations know as jagging.
The important implication of Mr Vernon’s intention to start Pump A is
that it is recognised as dangerous practice to start a pump with a relief line having
only a single PSV (like the pump under consideration) if that valve has been
removed. The main need to have a PSV present is that if the pressure in the
pump is suddenly increased beyond its normal operating limits by a surge in
pressure then the PSV will automatically open and relieve pressure by allowing
some of the condensate to escape to flare. To jag a pump will introduce to it a
certain sudden surge in pressure. Moreover it was practice on the platform that if
the open end of any line was closed-off by a blind flange then pressure would not
be re-introduced to the line without the blind flange being pressure tested. There
was satisfactory evidence that if a blind flange was properly fitted with its bolts
adequately tightened then it should be able to contain the flow material in the line
without significant leakage. Presumably the practice of pressure testing (which
seems to have been a mandatory requirement on the platform) was a double
precaution to ensure that a particular blind flange had in fact been properly fitted.
There is no doubt that the prevention of hydrocarbon escapes was perhaps the
major safety consideration on the platform. At the time that Mr Vernon was
proposing to restart the pump there was no suggestion that the blind flange on the
relief line had been pressure tested. Thus the pursuers’ case begins with a
situation that just before the time the accident occurred Mr Vernon was
proposing to initiate a procedure that the witnesses recognised was irregular and
dangerous. The connection in time between the explosion and Mr Vernon’s
852
highly irregular act must make the re-pressurising of the pump a prime suspect as
a cause of the accident.
Of course a declared intention to commit an irregular act would not alone
be enough to prove that this act had occurred and caused the accident. However
the fact that there were two distinct phases in the annunciation of gas alarms just
before the accident indicates the likelihood that there were two distinct escapes of
gas separated by some minutes. Dr Davies had no doubt on this point. The
introduction of condensate by way of jagging the pump (assuming that the relief
line leaked) would provide just the explanation for the two leak episodes. So far
as the evidence goes nothing else was occurring on the platform at the time likely
to result in a two stage leak. Defenders’ counsel suggested that an escape of gas
from a relief valve could have created a two stage leak (such as for example
when compressors tripped). This may be an interesting possibility but it was not
explored with any of the expert witnesses. It is also to be noticed that Mr
Richard must have arrived at the east end of Module C just before the explosion.
He would it is to be assumed pass directly to the east end of the Module since
that was where he had to fulfil the urgent task of tracing the gas leak. He was
only there for a short time before the accident but nevertheless the fact that Mr
Young did not pass him on the stairs combined with the evidence of Mr Grieve
would suggest that he had at least a short span of time before he was consumed
by the explosion. Mr Richard made no immediate report of gas over his radio.
This may be consistent with a situation where the leakage was not continuous.
The airflow in Module C at the time of the accident was from west to east
so that if there had been an escape from PSV 504 some of the detectors at the
east end of the module are those that would be expected to initiate an alarm. The
853
detectors at the said end of the module were precisely those that responded just
prior to the accident. On the other hand none of the detectors in Module B
signalled a gas escape in that module. I have already expressed the opinion that
the evidence viewed as a whole does not suggest that all the relevant detectors in
Module B could have been inoperational. Thus on the detector evidence alone
Module B could be excluded as the source of the leak. However the evidence
pointing to that result does not depend on the detectors alone. The probability is
that the Oil and Water Operators were working in Module B until the explosion
but they did not report any oil leak or escape of gas. Moreover the blue flash that
was manifest when the explosion occurred is unlikely to have been caused by an
explosion of gas flashing off a pool of crude oil in Module B. I accept the
evidence of Dr Drysdale who on this matter was supported by Dr Mitcheson.
The evidence of Professor Magnussen on the point was not very clear and
somewhat tentative. There were no process upsets signalled by any of the
process alarm equipment in Module B nor did the Oil and Water Operators on
duty report such upsets. Moreover the B/C and C/D firewalls were definitely
opened up by the explosion. Apart from there being incidental damage in the
Control Room complex in Module D Mr Bollands and Mr Clark were swept
across the room. Mr Bollands described the experience as being like the wall
coming in. On the other hand the A/B firewall did not fail - at least not to any
significant extent. The C/D firewall was the strongest of these firewalls. I do not
accept that it was shown that a pressure piling mechanism could have played any
part in the explosion. The involvement of such a mechanism would have
required an accumulation of gas in Module B sufficient to cause an explosion
there and then also sufficient to survive the dilution en route to Module C, and
854
form an explosive cloud there. The gas alarm patterns do not bear out such a
possibility. In any event there was no satisfactory evidence to show that pressure
piling was even a possible factor within the open ended Module C.
There are a number of features in the evidence from which (when they
are considered together) it can be concluded that the initial explosion originated
in Module C. In the first place there was the blue flash spoken to by Captain
Clegg which he claimed seemed to come from the mouth of Module C. Since he
had firmed up his evidence on this since the Cullen Inquiry I should have been
reluctant to place much store on this particular observation were it not that it fits
in so well with other evidence. Whatever doubts there may be about the
evidence of Captain Clegg I thought that he was an observant and fair witness so
that his evidence can be accepted insofar as it is reinforced by other evidence.
On the other hand it would not be surprising if a momentary observation such as
he was reporting contained some inaccuracy. I have certainly no reason to doubt
that he saw a blue flash and indeed it would be strange if such a detail as the
colour of the flash had imposed itself in his memory unless it were well founded.
I have also no reason to doubt that he had seen the flash low down in relation to
the production modules. This is a detail that he seems to have been positive
about both at the Cullen Inquiry and before me. The one aspect of his evidence
that is transparently not satisfactory is his description as to how the flash had
extended along the west face of the platform both to the north and south of
Module C. Captain Clegg seems to have adjusted his evidence about the extent
of the flash between the Inquiry and the Proof. In any event he described his
evidence as being an “impression”. It is difficult to explain a flash along the
north west face of the platform in terms of an explosion at the east end of Module
855
C. However it is equally difficult to accept that such a flash could have been
caused by the explosion of a trail of gas stretching along the platform face.
Firstly this in all likelihood would have been noticed by personnel who passed
along the walkway just before the accident. It is not easy to see how a trail of
gas would have spread to the south of Module B (assuming the gas had come
from there) against the prevailing wind. It is not impossible that this could have
happened but unlikely. Nor does that hypothesis fit in with what was observed at
the time of the explosion. If there was an explosion along the west face of the
platform this alone could not explain the explosion which caused the initial
damage. It is difficult to see where a trail of gas along the platform could have
come from if not the west end of Module B. If there had been such an escape in
Module B then given the prevailing wind not all the gas would have emerged for
the west end of the module and one would have expected gas alarms to go off. If
the blue flash was caused by an explosion in Module B then one would have
expected the accumulated vapour within the module to explode at the same time.
As I have indicated it is unlikely that this would have been marked by a blue
flash alone. The hypothesis of Professor Magnussen was founded on the
supposition that the explosion and the fire seen in Module B were one continuous
event. This runs directly counter to the evidence of Captain Clegg. He observed
a blue flash which clearly was the initial explosion. It was followed by a
shimmering silence which may have been the effects of vibration. In any event it
was only a few seconds after the flash that, as a separate event a fire developed in
Module B. Dr Mitcheson thought that this gap in time was a important factor in
confirming that the explosion had been in C. What Captain Clegg described was
literally a flash so that a misdescription of its extent would in no way be
856
surprising. Moreover given the perspective he enjoyed in relation to the platform
a flash coming directly out of Module C could quite readily have seemed to
extend along the platform. I do not think it in any way destroys the hypothesis
that the initial explosion took place in C which is in any event supported by other
evidence.
There are a number of other factors suggesting that Module C was the
location of the initial explosion. Captain Morton also seemed a reasonable
witness although again it would not be surprising if his memory was not accurate
in every detail. However what he first noted was what appeared to be smoke or
dust coming out of the east end of Module C. There does not seem to have been
a fire at the east ends of either B or C. Moreover the first thing noted by the
witness Flaws was smoke rising above the east end of Module C. Thus again
there is evidence that the first incident of the explosion was in Module C.
Dr Drysdale, Dr Mitcheson, and Dr Bakke all confirmed that a blue flash
would be indicative of an explosion of a lean mixture and particularly of a cloud
of condensate at the east end of Module C. If the visible manifestations of the
explosion suggest that the initial explosion is consistent with a leak of condensate
then it is condensate which would have escaped from any leak at the blind flange.
The pursuers’ expert evidence was also to the effect that an explosion causing a
blue flash was only consistent with a situation where only part of the module was
filled with gas. This of course suggests a finite and limited source of fuel.
The evidence of Mr Grieve is important in relation to the location of the
explosion. Firstly he describes in graphic terms how the explosion seemed to be
just above his head. Like something dropping there he said. The location of the
source of noise is admittedly often difficult to pinpoint but is perhaps another
857
coincidence that as far as he was concerned the explosion seemed to occur above
his head in the general area of the suspect PSV. Moreover some fifteen seconds
or so after the explosion he noted a fireball burning in the roof space in a location
not far from the location above it of PSV 504. Insofar as this was dealt with by
the experts they thought it consistent with a fire in Module C which had been
fuelled by heavy gas dropping through pipe penetrations. The defenders argued
that this phenomenon was possibly caused by unburned gas pushed ahead of the
explosive gases which had knocked Mr Young and Mr Grieve over. It was said
that these might have accumulated in the roof space and then somehow been
ignited. This theory was not really explored with the pursuers’ experts. Given
that the explosive gases were moving at speed when they knocked Mr Young
over it is not entirely clear how unburned gas pushed ahead of the flame would
accumulate presumably relatively stationary in the roof space under
consideration. The defenders argued that the penetration in the ceiling between
the 68-foot level and Module C were probably sealed. I do not consider this to
be an important point. Whatever their condition before the explosion this had
caused considerable vibration that had dislodged much material such as lagging
and presumably sealant. Thus I consider that the likely cause of the fireball
(which occurred about 15 seconds after the explosion) was a leak of unburnt gas
through the ceiling from a fire burning in the floor above. In any event it is a
significant coincidence that this phenomenon should emerge from a situation
quite close to the PSV site. An other important implication of the fireball is that
if the gas dropped through the ceiling above this suggests that the fuel was a gas
heavier than air such as a propane mixture.
858
Certain observed manifestations of the accident, although possible
consequences of an explosion in Module B, are more consistent with the
explosion having occurred in C. These include the damage to the Chantry Riser
Gantry, the fact that Mr Elliot had been beaten to the ground in a position below
module C at the time of the explosion, and the fact that MOL panels which had
been situated in Module C had been projected onto the west face walkway.
These matters would not be conclusive if each stood alone but taken together and
against the background of other events they fit very well into the supposition that
the explosion was in Module C.
Undoubtedly shortly after the initial explosion there was some fire in
Module C but much more extensive fire in Module B. Of course there was more
potential for fire in module B because it had much heavier inventories of oil and
condensate. Just how these fires happened to be fuelled is difficult to determine.
As I shall discuss, the fireball phenomenon in Module B seems to have been
fuelled by an escape of condensate but to maintain the fire in module B there
must have been and escape of oil. Dr Drysdale gave some views on how oil may
have escaped from the MOL. He is an experienced chemical and fire engineer
but not of course a mechanical engineer so that his views have to be regarded
with much care. The fact is that there is no doubt that shortly after the explosion
crude oil was escaping. Of course some of the lighter ancillary piping carrying
oil may have been damaged. The persons in the diving skid saw crude oil
running down the MOL as it passed through there. Of course once fire was
established the heat itself could cause damage. There was some fire in Module
A, on the skid deck and elsewhere on the platform. If it is evident that the
explosion occurred in Module C then it is inescapable that subsequent fires were
859
a result of this. Two unconnected accidents of the scale observed occurring at
the same time is beyond credence. Upon the original explosion there would have
been at least some projectiles when the firewall ruptured, considerable vibration
which may have affected fuel lines and equipment and of course heat and new
explosive forces.
Dr Drysdale and Dr Mitcheson convinced me that the likeliest fuel
feeding the fireball phenomenon in Module B which occurred about 15 seconds
after the accident is condensate. I accept their interpretation of Mr Miller’s
photographs. I also accept Dr Drysdale’s calculations which point to the fact that
there was likely to be just enough condensate in the condensate line to provide
the fuel for the fireball (which was in any event the consequence of a limited
escape of fuel). On the other hand Professor Magnussen’s attack on
Dr Drysdale’s fuel calculations was not persuasive and in any event I think had
been put together very much at the last minute. The defenders said that there was
no explanation for the gap of about 15 seconds between the explosion and the
emergence of the fireball (the point being made was that if the condensate line
had been severed by a projectile there would have been no gap). The defenders
therefore sought to persuade me that the initial cause of the accident was flashing
gas from a pool of oil followed by a pool fire as the fire heated up. I have
already made the point that the initial explosion and the subsequent fire appear to
have been separate events. There is also the evidence of the witness Mr Wood.
This witness observed a burst of fire from Module B with dimensions that must I
think have been the fireball. However just before this happened he heard a loud
metallic sound from Module B. This could have been due to equipment
changing state or even condensate under pressure escaping from an enclosed
860
space. The Nowsco tests confirmed that a leaking flange can create a noise
because of gas escaping from a confined space. I think this evidence of Mr
Wood confirms that there was some seconds delay between the explosion and the
escape of condensate. Exactly how this came about will never be known.
Perhaps the initial explosion damage combined with further local explosion or
changes in the line support system or deterioration in the state of the damaged
pipe from some cause was the explanation for a delayed escape of condensate.
The defenders relied upon certain evidence to suggest that perhaps the
B/C firewall was not penetrated by the explosion. For example Mr Grieve
approached towards the mouth of Module C after the accident and did not see
any fire from Module B through the west end of the B/C firewall. However this
kind of evidence is not very significant since by the times the very limited
observations were being made there was so much smoke that precise observation
was difficult. No one got really near to the mouth of Module C. I also found no
attraction in the theory of Professor Magnussen that fire and smoke may not have
penetrated through the C/D firewall to the north face of the firewall but rather
could have been swept to the north from Module B over the accommodation
module. This view did not get much support from the eye-witnesses who were
present. The witness Swales gave a limited support to Professor Magnussen in
that he saw some smoke and flame proceeding over the top of the platform.
However it is obvious from other witnesses that there was heavy smoke emerging
from Module D at the north face. Thus Mr Vernon before he died tried to enter
the east part of Module D to gain access to firefighting equipment but was unable
to do so.
861
For reasons which I have elaborated upon I do not think that the
phenomena observed at the Flotta Terminal have any adverse reflection on the
pursuers’ case on the cause of the accident. It should also be noted that there was
no evidence that the B/C fire door was open during the night shift. There was no
evidence that work in the area of the door was proceeding during the night shift.
If the door had been left open by the day shift then one would have expected the
Oil and Fire Operators to close it. Of course an escape of gas from B into C
through the door would have to progress to the alarms at the east end of C to
trigger the alarms there. Such gas would have had to be considerable in amount
to survive dilution. Thus other gas alarms would have been triggered.
Dr Mitcheson and Mr Cubbage both thought that an accumulation of
condensate at the east end of Module C was a possible cause of the accident.
Dr Bakke confirmed the view that a local accumulation in the module was
likelier than a gas cloud that filled more than a proportion of the module. If gas
in Module C had extended materially to the west of PSV 504 then the progress of
the gas through the Module would have initiated other alarms than those which
responded. Moreover the explosive flame that came into the 68-foot level
included hot gas. Mr Young got his eyebrows singed. However the gas that
penetrated to the Control Room was cold gas and the Dr Mitcheson and
Mr Cubbage considered that this indicated that the explosion had been caused by
a limited amount of gas perhaps corresponding with what could have leaked from
the pump. Dr Mitcheson considered that a mass of about 50 to 60 kilograms of
gas would have been sufficient to cause the explosion witnesses described. This
is important evidence because the defenders did not challenge it nor lead
contradictory expert evidence. Indeed he thought these values represented an
862
upper bound. If there had been more than a limited amount of condensate
leaking then there would have been a more extended fire in the module. Dr
Davies considered that to explain the alarm pattern the initial explosion must
have been towards the eastern end of Module C. However he went further than
that. His view is that an explosive cloud collected in the north east quartile of
Module C would have set off different alarms to those which annunciated.
Accordingly he thought that the south east quartile of Module C was the likeliest
source of the explosion. This fits in with the theory that a leak from PSV caused
the accident. Indeed none of the experts suggested other equipment at the south
east of the module that could be considered a likely cause of the accident. Dr
Davies with his modelling exercise eliminated an intrusion of gas from Module
B. In any event such an escape would have triggered off alarms in B.
The evidence points unambiguously to the fact that the explosion
occurred in the south east segment of Module C. This means that if PSV 504 had
nothing to do with the accident there is yet another formidable coincidence. The
defenders say that the closeness in time between the change over to Phase 1
Operation and the accident is also a coincidence. However the new procedure
had been operating continuously for several days without apparent problem. The
possible implication of the changeover was not explored with experienced
witnesses such as Mr Wottge the Process Engineer. There was evidence to
suggest that when the gas flow was altered when the reciprocating compressors
were unloaded and recycled the flare arrangements operated and flaring
increased. The experts were not asked to identify any other equipment at the
south east end of Module C which night have been vulnerable after the
changeover. Pump B had tripped on one other occasion after the changeover. It
863
is unlikely that this pump was leaking since men were working next to it. On the
occasion of the trip before the accident Mr Vernon suspected that this was due to
a lube oil fault. If the pump was merely being overworked one might wonder
why it did not restart. Certainly the centrifugal compressors tripped just after the
first gas alarm. No expert evidence was led to suggest how these compressors
could have caused a leak. The tripping of the compressors appears to have been
a normal accompaniment of recycling and unloading the reciprocating
compressors. The compressors tripped after the first alarm and if one was
causing the leak it is perhaps odd that all three tripped just before the explosion.
If the leak was internal to a compressor it would perhaps be curious to see all
three showing alarms. The annunciation of alarms associated with all the
compressors seems rather to suggest a gas source external to the compressors but
common to them. The relief valves of the compressor were situated in Module B
and if there had been leaks there we would have expected alarms and some
indication of explosion or fire at the east end of Module B.
I agree with Dr Davies that it is quite possible that the detector G 103/1
was a candidate for the detection of a gas cloud escaped from PSV 504. Its
ability to detect gas would depend on a fine balance arising from the exact
position of the walkway, the position of the head of the detector, and its
relationship to other structures that might have hemmed it in. If other factors
pointed to it having been a detector that triggered then I see nothing to exclude
that possibility. Indeed Dr Davies thought that because the escaped gas had a
clear path to the detector being considered it was the likeliest candidate to give
the first alarm.
864
Dr Davies gave evidence of his modelling exercises to test the pattern of
gas releases needed to cause the alarm patterns that were observed. The
defenders point out that he was asked to assume that the gas which leaked was a
heavy gas and that is so. Dr Davies had no hesitation in accepting that the task
he had undertaken was complex and his results had to be viewed with care.
Indeed since the Cullen Inquiry he had modified his tests and results. There are
difficult technical problems in such as exercise as he conducted such as scaling,
calibration of test probes and making accurate allowance for the congestion
within the Module and the consequent turbulence. Dr Davies gained his basic
data from Dr Richardson, a fluid engineer who gave evidence about the structure
of the pump, and its GOVs and PSVs as well as the relevant flows of
hydrocarbon that one might expect under re-pressurising or leaking. The last
two witnesses were very well qualified and able which does not of course mean
that they were always able to arrive at the right conclusions in respect of the
complicated problems they were dealing with. The defenders brought a specialist
witness Dr Crofton about the mechanics of GOVs. His evidence was somewhat
theoretical compared with that of the men who actually worked with the valves
and also Dr Richardson had practical experience of valves which demanded
respect. I did not find that Dr Crofton contributed anything to the case which
affected the more general view that I can take from Dr Richardson and Dr
Davies. I have no doubt that with a staged jagging of the pump which leaked the
kind of mass of hydrocarbon which could have generated the explosion could
have been generated. Moreover if the gas released were a gas heavier than air
then two releases could create the alarm patterns observed. The defenders attack
this approach on two grounds. The first was that the first stage of the jagging
865
would inevitably be of neutrally buoyant gas. In an elaborate extrapolation from
pieces of the pursuers’ evidence the defenders sought to persuade me that a
staged escape from the PSV could not produce the alarm patterns that had been
observed. They claimed that the condensate which would enter an empty pump
would flash off at lighter ends. Moreover the air plug at the top of the relief line
would a have to be expelled before any condensate leaked out. Their essential
point was that the material that would be expelled during an assumed first stage
of jagging would be neutrally buoyant gas. Such a gas cloud could not travel to
the end of the module without rising and triggering a C2 zone alarm and in
particular G101/1. This they say follows inevitably from the conclusions of
Dr Davies. In the first place it has to be observed that the defenders’ theory was
not put specifically to either Dr Richardson nor Dr Davies. Although both these
experts had been asked to assume that the escape of gas would be heavier than air
this assumption did not appear to trouble them. The behaviour of condensate
when it enters the pump and thereafter leaks will be a delicate balance between
pressure and temperature. If heavier ends flash off there will be mixing and
stratification of the different gases. In any event the prospect of the gas cloud
missing alarms will depend on the relative heights of the detector and the PSV
leak. These heights were not absolutely clear. Obviously the pursuers
anticipated the escape of heavier gases since they replaced some of their detectors
at lower levels to account for this. Thus not only are the defenders constructing
scenarios that were not put specifically to the pursers’ experts but the reality is
that the observed phenomena suggest that the explosion was of a low lying
material. I refer in particular to the fact that the blue flash was said to be low in
relation to the modules and also the fireball observed by Mr Grieve. The
866
material which escaped from the PSV indeed seems to have avoided setting off
the C2 alarm and that could confirm that the defenders’ explanation of events is
not inevitable and indeed I do not think that it is. Even assuming that the
defenders’ postulation of what happens when the condensate enters the pump is
correct it does not follow that the pursuers’ case will fail. As I have mentioned it
cannot be assumed that the pump was empty when the first jagging which gave
rise to a detectable leak took place. If the pump was jagged before the first gas
alarm we do not know precisely how this was done. The first stage of jagging
may have consisted of Mr Vernon or Mr Richard allowing condensate into the
pump in say two applications of the push/pull button. This could have caused an
expulsion of lighter gases which did not contain enough hydrocarbon to trigger
an alarm. Then as the pump filled the condensate or heavier gas would begin to
leak out and when it reached the zone three alarm it would trigger an alarm. The
second stage of jagging would then consist of what must have occurred when Mr
Grieve arrived at the scene. In this operation the latch may have been opened
rather longer to be sure of fully pressurising the pump but that would still be an
operation that would take less than a minute. The second operation perhaps
releasing a greater weight of material would set off the second pattern of alarms.
The defenders make another important point since they claim that Dr Davies
accepted that his modelling results would be affected if there was a scaffolding
below the site of the blind flange. This is not quite an accurate representation of
Dr Davies’ posit. What he was saying in effect was that he could not accurately
model the situation taking account of the scaffolding. He did attempt to model
the scaffolding by placing a block beneath the presumed leak site but this he
accepts was not very satisfactory. In effect he found himself unable to model the
867
scaffolding without details of its structure, its location in relation to the blind
flange, the equipment surrounding the scaffold, and the size and direction of the
leak. It became too difficult to perform precise modelling taking into account the
conjectural factors introduced by the scaffolding. However Dr Davies did not
say that the presence of scaffolding made it unlikely that the alarms were
triggered by an escape from PSV 504. In fact even in the knowledge that the
material which had been introduced to the pump was said to be condensate and
with the additional knowledge about the scaffolding he appeared to accept that
leaks from the PSV could account for the alarm sequence. The scaffolding of
course admittedly could have affected the accuracy of his modelling. There was
however room for a combination of events that could have caused the alarms to
go off and that was consistent with a phased attempt to re-pressurise the pump.
Thus the main lesson that can be taken from the evidence of Dr Davies is that the
pursuers’ hypothesis, if supported by other evidence which fits well together, is
eminently possible.
The parties spent a considerable amount of the time occupied by this
proof seeking to establish the structural strengths of the firewalls and the
explosive overpressures that would be need to cause their collapse. I was never
entirely sure what the pursuers’ intention was in undertaking this formidable
exercise. One objective certainly was to seek to demonstrate that an explosion
sufficient to destroy all or part of the firewall (and in particular the south-west
end of the B/C firewall as viewed from C) would have generated projectiles with
sufficient energy to breach the 4-inch condensate line in Module B. Another
problem may have been that these are extremely extensive proofs and thus parties
may not always have been sure what precisely their opponents were planning to
868
do - particularly in reply. Thus the pursuers may have been seeking to protect
themselves against evidence from the defenders to the effect that the pursuers’
hypothesis is impossible.
The experts were agreed that whatever the value of hand calculations in
the exercise (and this itself was in dispute) a finite element computer modelling
or at any rate an exercise assisted by computer modelling was likely to arrive at a
more accurate result. The pursuers certainly recognised that because as I have
earlier indicated their original intention was to lead evidence of such modelling.
They had to abandon this plan but I think it is clear that the failure of the
pursuers to approach these questions by way of a computer exercise was not due
to any deliberate planning but rather due to faulty organisation. It also had to be
noted that the introduction of a computer model does not remove every
difficulty. It simply creates different difficulties. The experts agreed that
however the matter is approached the dynamic analysis of structure raises many
profound engineering problems. If computer modelling is used it is common to
find questions raised about the appropriateness of the model or the adequacy of
the input material and there was even a foretaste of this in these proofs. It cannot
therefore be said with absolute confidence that a computer analysis of the
firewalls in this case would have saved a massive amount of time. However I
should definitely have expected such an exercise to save some time and probably
even a lot of time. There was also a fair prospect that it would have produced
more reliable results.
In these cases the pursuers led evidence based on manual calculation from
Professor Fenner. He was a computational analyst and recognised his incapacity
to do a complete dynamic analysis of the firewall by manual methods. He did do
869
a static analysis of the firewall using beam theory and also he worked out
comparative strengths of firewall components. I think it was largely in
connection with the last-mentioned material that the pursuers were relying on
him. They may also have hoped to use Professor Fenner to provide the
foundation material for the exercise by Dr Cox. On the other hand the witness
Dr Palmer did a complete dynamic analysis of the B/C firewall by hand
calculation. The defenders attempted to diminish the value of such an exercise.
However as Dr Palmer sought to remind me on a number of occasions, until
recently engineers used to manage all their work by way of hand calculation. In
any event the result of the pursuers’ approach is that I was assailed for many
months with complex mathematics (at least so I judged it to be). Because much
of this was difficult the witnesses producing the evidence required to spend much
of the time explaining what they were doing and even with their expert help there
were areas of the evidence which were close to being unintelligible to a non-
scientist. A look at some of the oral evidence, the productions and the
calculations on the flip charts will make this point perfectly obvious. When it
came to submissions much of the detailed mathematics was not challenged.
Whether this was out of deference to my faint antipathy to the material or
because it was not considered helpful to the parties’ submissions I do not know.
However I am left with wondering why much of the mathematics could not have
been agreed in the first place since little of the pure mathematical calculation was
challenged. This would have saved a lot of time. There may of course have been
practical problems about such agreement.
The approach of the defenders to this area of the case has to be noticed.
The defenders brought Professor Reid to challenge Dr Palmer’s methodology.
870
He was a very capable witness and I am sure that, in particular, he was quite
capable of producing his own quantitative analysis to illustrate the impact of the
points he was making. However he had not been asked to do this and indeed
only occasionally attempted it. Thus the defenders’ approach was to attack Dr
Palmer’s methodology but they made no attempt to themselves establish the
answers to the problems being considered.
Dr Palmer, Professor Fenner and Professor Reid were all in my opinion
highly competent and exceptionally well qualified experts. That is not to say that
their evidence often agreed. It is acknowledged that the theoretical structural
problems in the kind of exercise I have to consider are very difficult and experts
disagree over many aspects of the methodology. I can form certain broad
opinions about the general approach of the witnesses. However given witnesses
of such quality unless I can see a clear way through a particular problem I do not
think it would be appropriate that I should attempt to resolve theoretical and also
practical differences that have divided the engineering profession for years. I
have set out above some of the detailed issues that arose in the proof but do not
think it necessary or advisable to resolve the problems that arise other than in a
broad manner and to the extent that I have already dealt with them.
Certain differences in the witnesses are significant. Professor Fenner had
a narrow remit. He was mainly used for his comparative analysis of components
and his results in these respects were not seriously challenged. Dr Palmer struck
me as being very experienced in the resolution of practical problems so that his
approach was to look for broad and pragmatic solutions. Professor Reid on the
other hand was looking for solutions that were more scientifically rigorous so
871
that he was inclined to be concerned about issues that in practical terms Dr
Palmer thought could be looked at more broadly.
I should perhaps also add for good measure that I had no occasion to
doubt the qualifications of Dr Bakke and Professor Stollery.
The important point is that if I conclude that on the basis of the other
evidence I have considered it is clear that the re-pressurisation of the Condensate
Injection Pump resulted in a leak at the blind flange and that this caused the
explosion it is not critical whether the strength of the firewall or its capacity for
developing damaging projectiles is established or not. If an accumulation of
condensate at the east end of Module C exploded then I think that it is
inescapable that all the damage to the platform that ensued after the explosion
was triggered-off by it. Thus if there is evidence that the B/C firewall failed (and
I am satisfied about that fact) then it may not matter precisely how strong the
firewall is. If the firewall fails and this is followed by a conflagration it may not
matter precisely how this has developed. Of course I would have to be persuaded
that an explosion of the quantity of hydrocarbon that could have leaked from the
blind flange would on the face of it be sufficient to damage the firewalls and set
off fires in Module B. If the defenders were to have shown that an escape from
the pump could not possibly have destroyed the integrity of the firewall then of
course I should have to reconsider the other evidence pointing to the blind flange
as the source of the tragedy but the defenders certainly have not done that.
It was pointed out that there is a difference between the results of
Professor Fenner’s static analysis of the firewall and that of Dr Palmer. The
argument was that the pursuers’ experts contradict one another so both should be
disregarded. Professor Fenner brings out a failure value for the firewall of
872
0.007 bar as compared to the value of 0.1 bar produced by Dr Palmer. However
we are not comparing like with like. Professor Fenner’s result was arrived at by
way of a beam analysis. However Dr Palmer’s value was achieved as a result of
a plate analysis. This clearly is a more complete methodology since it takes into
account the effect of lateral support. Moreover Dr Palmer’s result is supported
by Dr Bakke who expected that the failure pressure of the firewall may have
been even higher than Dr Palmer found. However it has to be noted that Dr
Bakke was only expressing a general impression and he never seriously
challenged Dr Palmer’s results. Moreover in respect of the collapse of fairly
complex and substantial structures such as the firewall then being himself a
specialist in gas dynamics he was prepared to defer to the experience of a
structural engineer like Dr Palmer. Dr Bakke also accepts that the calculation of
an overpressure that might develop in a structure like Module C from the
explosion of a specific quantity of hydrocarbon is a difficult and sensitive
calculation. One very important factor is turbulence and this is very hard to
assess accurately. The volumetric size of the cloud can affect the overpressure.
The very source of ignition can affect the overpressure by a factor of five. Thus
I do not think that Dr Bakke ever seriously challenged the general evidence of a
witness such as Dr Mitcheson that the explosion of the 40 or 50 kilograms of gas
that could emerge from a leaking injection pump could cause an explosion that
would pierce the firewall. Indeed he supported their point of view and indicated
that a cloud which occupied about one-tenth of the Module could generate an
overpressure of 0.5 to 0.6 bar. He thought that the overpressures which the
pursuers were basing their case on were rather conservative.
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Dr Palmer was a highly experienced engineer. He was prepared to
venture a conclusion for a dynamic analysis of the strength of the firewall. His
results even by his own admission must be taken as very approximate.
Professor Reid has expressed the view that Dr Palmer’s results are seriously
unreliable but he has not himself offered quantification of this view. Thus I am
left with only one complete analysis of the overpressure that would be required to
destroy the integrity of the firewall. It is obviously not the only result that an
experienced engineer might arrive at. However it is the only one I have and it
comes from an expert well able to advance justification for his methods. It also
has to be restated that many of the objections that were eventually suggested in
relation to his methods were not put to him. Thus in deciding what reliance if
any I can place in his work I must recognise that the approximate validity of his
conclusions fit in well with the other evidence in the case. On balance I do not
need to take any more from his evidence than that the destruction of the B/C
firewall by an explosion of such gas as may have leaked from the injection pump
is probably quite possible. Even if his calculations are not accurate there is
general evidence which I accept that escaped material from the pump would
generate sufficient pressure to destroy the integrity of the firewall.
The matter of the projectiles is more difficult. Again Dr Palmer
calculates the projectile force that might be expected from such part of the
firewall as is forced loose by the explosion. Professor Stollery gave evidence
about shock tube theory but for the reasons which I have already discussed I do
not think his reservations on Dr Palmer’s results are conclusive. Professor Reid
is a particular specialist on the impact of projectiles and I accept that his views
demand respect. However some of his opinions involve fairly difficult and
874
controversial areas of his subject. Once again I am handicapped by the fact that
much of the pursuers’ evidence was not put to Dr Palmer. Thus although on this
branch of the case I can only have limited confidence in Dr Palmer’s views and
could not rely upon them if they stood alone equally he is too experienced an
engineer to have his views totally discounted. I have now arrived at the point
where I can decide that the accident occurred because of an explosion in Module
C. This explosion resulted from the fact that Mr Vernon jagged Condensate
Injection Pump A at a time when the essential PSV was not in position. The
explosion caused a substantial part of firewall B/C to break up. This was the
cause of fire developing in Module B. I cannot make a finding as to precisely
what energy fragments of the wall would have developed as they broke away. I
am not sure that this matters. Just how the fragments impacted on the equipment
in Module B will never be known. However I think it is clear that the impact of
the fragments from the wall had sufficient force to do some damage. Dr Palmer
with his experience must be right at least to that extent. I think it probable that
the condensate line in Module B sustained some damage from the explosion.
The same applies to the smaller bore oil lines. Just how damage to the
condensate line operated to cause the escape of condensate cannot be known but
with such an explosion the connection not only seems possible but it is shown to
be possible by what actually happened.
The defenders contended that Mr Grieve was the only eyewitness present
at the 68-foot level when Mr Vernon would have required to jag the pump if the
second flurry of alarms is to be explained. That fact is true and the defenders
therefore argued from it that since Mr Grieve did not see Mr Vernon jag the
pump it could not have happened. I cannot accept that conclusion. Mr Grieve
875
was himself occupied in helping to try and restart Pump B. He was not really
aware what Mr Vernon himself was doing and said so. The jagging operation
would have taken less than a minute and would have been carried out relatively
close to where Mr Vernon is described as having been seen. It would have been
quite surprising if Mr Grieve had noticed and remembered all that Mr Vernon did
in a short period when Mr Grieve himself had detailed work to perform. Mr
Vernon had indicated to others that he was intending to start Pump A. He was
awaiting an electrician so that he could complete that objective. He could not do
much before he had his electrician but it would have been natural that he would
try and get the pump ready for starting so far as was possible before the
electrician came. It was also to be expected that if he had changed his mind
about using Pump A he would have instructed the cancellation of the electrician.
There would be no point in de-isolating the pump and then requiring to
electrically isolate it again. The preparatory work would include re-pressurising
the pump. The jagging operation would only take a few minutes in total so that I
see nothing peculiar in that at the same time as he dealt with pump A Mr Vernon
should continue efforts to restart Pump B particularly when an instrument
technician is coming on the scene.
If condensate came out of the Pump system during jagging then the only
probable explanation is that Mr Sutton was careless. The evidence shows that
blind flanges should not leak if they are properly fitted. Therefore I must
conclude that Mr Sutton did not fit the blind flange properly. I do not know why
he did not take care but there are various possibilities such as that he found the
flange troublesome to fit in a confined space or that he expected the valve to be
refitted before the end of his shift and therefore did not bother to do his job
876
correctly. I have already found that the defenders’ arguments on foreseeability
and novus actus interveniens are not well founded.
Insofar as Mr Vernon did not know or recollect that the PSV 504 was not
in place I find that he was careless. However I cannot find that he was reckless
or acting so as to show wilful misconduct.
877