i. Flame extinguishment atter lighting up due to 1

a. Lack of ventilationb. Poor draft0. lnsuificient air supplyd. improper gas supplyj. Biowing out of torch used for iighting up, either due to weak torch oropening too much gas.l<. Using improper tools, when opening flangejoint of gas iines.

In.

one POl§_<_)NlNG ANQ FIRST-AIQ

Carbon Monoxide combines easily with the haemcgiobin of the blood, formingunstable compound cailed oarboxy-haemoglobin. The affinity of Carbon Monoxide forthe blood is 2'30 times more than that of oxygen. So, even if a small amount is presentin the air, the haemoglobin will absorb CO in preference to Oxygen. When thishappens, the capacity of the haemoglobin carrying oxygen to the tissues of the body isreduced. More and more breathing of CO displaces oxygen, causing the body to sutferfrom oxygen starvation resulting in asphyxia.

sourzces OF CARBON Mgiygxiog IN sT§_eL Pi.A_rg_1;

1) Coke Oven gas — 6% to 8%

2) ' Blast Furnace gas - 25% to 30%

3) L. D. Converter gas - 65% to 70%

4) Mixed gas — 15% to 30%

5) Foundries « Cupola Section 13% to 17%

SYMPTOMS AND EFFECT

a) Headache e) ‘lightness in chestb) Dizziness i) Weakness in limbsc) Mentai dullness g) Vomiting

d) Yellcwness in front of eyes h) Unconsciousness

PERMISSIBLE LIMIT

1. Threshold Limit Value (T W) = 50 ppm or 0.05? rngllt.-_—-0.005% for 8 hrs. duration.2. Short term exposure limit (STEL) = 400 ppm for 15 min. duration

FIRST Alp IN orig OF eras POiSONlN(_3__

1) Do not become panicky

2) Take the victim to the fresh air against the wind direction.

3) Loosen the tight fitting clothes, shoes and belt of the victim.4) Ask the victim (if conscious) to take longer breathing.

5) Arrange Oxygen for the victim.

6) if unconscious, send the victim to nearest Medical Centre.

7) inform Gas Safety to take sampie of the area.

1) Never crowd around the victim.

2) Do not allow the victim (if slightly unconscious) to sleep.3) Never give anything to eat or drink.

4) Do not allow the victim to run.

5) in no case leave the patient alone.

6) Do not ignore any symptoms.

GAS SAFETY RULES

The gas safety rules are laid down for the guidance of all workers particularly

those connected with the gas fired furnaces, drying ovens and maintenance of gaslines. These rules refer to hazards of gas poisoning, gas explosions and fire.

1

'10

11

_lt is prohibited to make a fire or to smoke near the gas valves, gas line joints,

oompensators, water drainers, in gas booster and mixing station and where gasjob is going on.

No one should take rest or sleep near gas valves gas lines joints, seal pots andin gas dangerous areas. a

No gas burners shall be kept burning inside the furnace or in ciosed spacewithout an attendant.

Gas masks should be used while working in atmosphere contaminated withpoisonous gases.

The maximum allowable concentration of Carbon Monoxide in air is 0.05mgflitre for eight hours duration.

Not less than two persons should be allowed to work in the gas hazardousareas.

Wearing of shoes with iron nails on gas lines are strictly prohibited.

Control room, booster house or other room where gas pipes and impulse linesare taken for connection to instruments, should always be properly ventilated.

When a furnace is taken down for repair, a blank plate should be inserted intothe gas main preferably on the down stream side of the valve.

When some portion of a gas line is to be isolated for repairs, aublank plate mustbe inserted, even if the valve or valves are closed.

All steam points, bleeder pipes and valves should be pre-checked beforeblanking or deblanking job in the gas line. The first steam point should be nearto the place of blanking or deblanking. Gas, steam and air should freely pass

through bleeders.

12

13

'14

15

‘I6

‘i7

18

'19

20

21

22

23

24

25

when small furnaces are not in operation the pair of valves before the burnershould be closed and the bleeder between them should be kept opened. if thissystem does not exist, a blank must be inserted alter the valve.

The gas equipment, water drainers etc. should be inspected periodically bycompetent persons. All joints, valves, cocks, and water seal should be free fromleakages. Gas leakage should be rectified immediately and in the mean—time nobody should be allowed to stay in that area.

Checking for leakage of gas should only be done by soap solution or by GarboMonoxide gas monitor. '

F-‘or welding jobs on gas lines, it must be done only after a blank plate is insertedbefore the piece where welding is to be done and the line has been steamedout and proper sample analysis has been carried out.

All gasmen and workers dealing with gas equipments should be regularlytrained in using gas masks, first aids (including artificial respiration)

"Gas Danger“ or Caution Boards should be fixed at all the gas dangerous

places in all the shops.

When working on gas lines at height, a suitable platform with convenientescape routes should be erected.

Never use naked light in the vicinity of any enclosed space which may containinflammable gas or hear any gas main or equipment.

No welding 8. cutting jobs are allowed in the areas where gas is likely to bepresent without clearance from Gas Safety.

All those who are required to work in gas hazardous places and all those whoare connected with the maintenance of gas lineslequipment and operation ofgas fired furnacesfdryirrg ovens must undergo basic and refresher course inGas Safety Practices.

For all daily routine jobs in the shops a job card should be filled up beforestarting the work. Such job cards are issued by Gas Safety Section andavailable with Gas Safety Man/Gas Safety station attending the job.

All shop in-charges snail arrange to draw out emergency plan and day to dayoperational instruction in connection with use of gas in their shops, whichshould be made available in the control roomslproduction control, all the time.

A systematic scheme of gas lines in the shop indicating all the valves, throttles,bleeders, water drainers, position of steam points and position of isolating pointshould be displayed in the control room, Such a scheme helps in a normal workas well as in emergency situations.

Avoid the formation of expiosive mixture by purging the gas main with steam orNitrogen .

262728

29

30318233

34

Prevent the suction of air into the gas main under all circumstances.

Routine maintenance of gas lines, taking quick action for stopping ieakageswhen found, proper ventilation of enclosed spaces quick steam flooding

' arrangement and good house keeping help to prevent explosion.

No gas job shouid be carried out in night hours unless in case of breakdowns oremergencies.

Explosion proof eiectric lights must always be used for the inspection of insideof gas mains and furnaces and enclosed spaces where traces of gases arelikeiy to be present.

A manometer should installed in the gas line on which work is going on underreduced gas pressure. it should preferabiy be nearest to the point of work.

Persons engaged in the gas job must wear cotton cloth, hand gioves, safetyshoes, helmets, goggles, fire resistance suit, etc. '

Gas job should not done in the premises which are not well ventilated or whichare close to running furnaces.

The area of work during gas job should be properly cordoned otf and entry ofunauthorised persons should not be aliowed

in case of emergency if gas job is under taken in closedisemi ciosed areamonitoring of gas concentration must be ensured.

§AFETY §YSTEM WORK PROC§DUR__E_ 8- PROTOCOL FOR GASHAZARDOUS JOBS

The danger which may arise from faulty or careless handling of gases or

equipment associated with their handling, may be broadly into two classes 1

_(i)

<2)‘

'1rgasesetc. to safeguard persons and equipment.

Gas poisoning due to the presence of Carbon Monoxide.

Injuries to persons andior damages to equipment caused by burns orexptosions.

It is, therefore, necessary to understand the basic safety principles in handling,and equipment such as pipe lines, lighting up and shutting down of furnaces,However," the following general safety

precautions are given as a guldeiine to understand the safety aspect better.

(l)

at Gas pistrlbution Svstem

Gas Pressure :- For the safety of the total gas distribution system, the gaspressure in any of the gas mains including the departmental mains should not

' be allowed to fell below 100 mmwo.

(ii)

if the pressurefalls below the above mentioned safe limit, there are chances of ‘

air enteringinto the—gas,:;rnai_n_. and‘ causing backfires at the consuming end,

-»which "may affect the gas "distribution mains. Under such‘ circumstances, it is

absolutely necessary to curtail the consumption, as the gas pressure comesclose to the above mentioned critical limits. The consumption of gas byconsumers should be totally stopped and water seals should be made up orvalve should beclosed ifthe pressure-‘tails below the safe limits and EnergyCentre should be informed.

Water Drainers :- Water drainers of standard type are to be provided in gasmains. The water drainers with their water inlet, drain and overflow valves-andconnections should regularly be inspected and should be in a condition to befilled up at" a short notice. The valve should be of gate or cook type in goodoperating condition and easily approachable. Low pressure water drainerlHighpressure water drainer should be used depending upon the gas line networkpressure. i

Bieeders and Steammltrggan purging cognection 1- The steamiblitrogenpurging connection should be at the start of gas pipe after the isolating valve,while the bleeder should be at the other extreme end of the gas pipe. Thebleeder on gas pipes should have gate valves at the tapping point. The bleeder

' should discharge gas in open space at a suiticlentiy high level, avoiding, places‘where men work or E.O.T. crane power rails run, which may ignite the gas.

in any case, particular attention must be paid, when operating bleeders, so thatthe gas is not allowed to blow over men working in the vicinity. Bleeciers andsteam connections must be inspected periodically.

The bleeder height should be minimum 6 feet above gas line. Proper approachshould be there to operate the bleeder valve.

l lnsggction of Gas Lines

a) ‘Gas Lines :~ Gas lines and accessories should be inspected thoroughlyat least once in a month. Shop should carry out joint inspection withEMD once in a year.

b) N. D. T. :— Thickness measurement of the gas line should be carried outonce in a year in order to assess the pipe line thickness for repair!replacement of it.

Charging of gas line headers

The following procedures to be adhered to, after the testing of gas line :—

a) Purge the gas line upto the end bieeder.

b) Deblank gas line as per standard gas safety practices.

cl‘ Charge the gas line with inert media uptc the end breeder.

cl) Stop steamlnitrogen and purge the gas from end bleeder till oxygencontent comes below 1%. -

e) Finally close the end bleeder, and disconnect steaminitrogen hoseconnections.

Pnocgourte or= siiutoowu or: arms MAINS ANg_§ouIPM___rg_nT FOR l3§r_e1;Igwgnk iNc;__u_ome gyrrme rwg_L_r_:>iNo age

PLANNING

Proper plan of work should be drawn out by the department concerned with thejob (owner of the assets).

(a) For repetitive work, the plan should be drawn up by the shop. Where necessary,the expert agencies should be consulted. T ~

(b) For new jobs (Non-repetitive), this plan should be-scrutinized by the Chief ofi Energy Management, Chief of the Fire Services and Chief of Safety.

(o) The plan should be drawn up well in advance. The plan of work should ensureproper (1) isolation (ii) Purging (iii) Ventilation (iv) Sampling and clearance (v)Supervision.

A scheme of gas line under consideration should be appended with the plan ofwork. it should show the locations of blanking, branches, bleeders, valves (size)steaming points (size and Nos), sampling points, diameter and total length of the pipeto be purged.

!SOLATlON

The isolation of the gas line is completed by the goggle valve operation or by ‘U’Seal water filling or by inserting a blank plates at predetermined locations with properplan. The work involves special technology of work and special preparatory jobs, like (i)size and type of blanks ' (ii) good working platforms with escape routes (iii)arrangement for lifting the blanks and jacking for making the gap (iv) use of nonsparking tools during working (v) adhering to the goggle valve operation check list.

IN CI-\SfiE_ OF ‘U’--SEAL ISOLATION

a) Overflow of water in ‘U’-Seal outlet must be ensured.

b) If the shutdown is for the longer duration a blank plate should beinserted on the non gas side.

o) isolating flanges and bleeder should be provided on both sides of the‘U’-Seal.

IN case or ocean: VALVE ISOLATION

a) No two goggle valves should have common hydrauliclelectrical system.

b) After goggle valve operation the power supply must be switched off andfuses should be removed to prevent the malfunctioning of it.

c) For maintenance of goggle valve an isolating flange should be providedbefore the goggle valve.

\_Cl

All branch pipes on the portion of the pipe to be isolated, should be cut oii by

putting blanks at the nearest flanges.

PURGING

1.

All steamlbiitrogen points, bleeder pipes and valves should be pre-checked forproper working. The first steam point should be close to place of blanking. ifsteam point is not there, care should be taken to see purging is done fromblank plate to end of pipe line.

2. As soon as blanking is over, the purging points and the end bleeder should beopened and the condensate should be drained out.

3. Progress of purging shouid be recorded. The aim shouid be at completereplacement of combustible gas from the point of blanking up to end of the pipe.

4. Where there is a chance of gas trapped in a section, special arrangement andcare must be taken to purge out this portion. Duration of purging wili depend onrate of steaming, size and length of pipe.

5. Purging to be carried out for sufficient time from isolating point to the endbleeder of gas line,

6. During Nitrogen purging persons should not stand near bieeder/openmanholes. '

VENTILAIION

Alter proper purging, all the manholes and end flanges, if necessary should be

opened, so that circulation of atmospheric air is welt established from one end to theother. Duration of ventilation will depend on size and total iength of pipe to be ventilatedand purpose of work.

SAMPLING AND CLEARANCE FOR THE JOB

1.

The Stearrilhiitrogen is to be closed and after it replaced by air, samples are tobe drawn from suitable locations. Suction tube of the sampling equipmentshouid be inserted well inside the pipe and sampie should be taken from upperpart of pipeline for gases lighter than air, and lower part for gases which are

heavier than air.Sampies are to be tested for explosive mixture by explosimeter. it should be

tested for carbon monoxide (0.05 mg./liter maximum) and analysis for oxygencontent (20.6% minimum).

Samples are to be taken again and the analysis is to be repeated if the sampieis abnormal.

When steam is available near the place where outtinglwelding job is to be done,as an additional safety measure, steam flow in the pipeline may be

maintained.

_ Cautions _:—

Sampling and testing equipment for gas testing should be in good condition.Final clearance for the job including cuttingfwelding will be given in the givenproforma when purging, ventilation and test resuits are quite satisfactory asascertained by joint inspection of Energy Management Deptt, Shoprepresentative, executing agency, Safety and Fire Department.

The sequence of jobs should be followed rigidly.

' 2) No operation should be conducted in haste, which will jeopardizesafety. ~

3) Night operations should be avoided unless in cases of' ' emergency.

4) No work should be taken up till the clearance is clearly given andaccepted by authorised person. All personnel except workinggroup for cutting operations, to be removed from the entire area.

5) isoiated equipment or main shouid be monitored for leakage tillrecharging and this should be logged.

6) The departments will maintain iist of authorised persons.

SUPERV|SlbN

The overall supervision will be under one Otticer earmarked for the job by theconcerned department.

Specific tasks would be assigned to particular persons, by name when possibleand by Designation in all cases.

A log book should be maintained to show the progress of work anddetermination of the end point of purging. All important operations connected tothe shutdown, when this extends over more than one shift, should belogged. -

NERAL LIGHTING UP FROG DURE FOR FU N C

GE E 3&1‘-:s

' iii.

Ensure -

’ a) Burner gas valves are fully closed.in) Main isolation valve is fully closed.c) Chimney damper is fully opened.d) Furnace doors are fully opened for ventilation.e) Chimney is having sulficient draft.

‘Open steantlhlg In the gas main and purge through and bleeder.

DE‘.Dlal"lK the Isolation pflim.

N. Open the main isolation valve and charge the header with gas.V. Close all the steamlhlitrogen points and disconnect them. _VI. V" Purge the header with gas through the end bleeder.

VII. Take gas sample which should show Oxygen less than 1%.Vlll. start air blower, keeping ‘rt at minimum level.

IX. Place a burning torch in front of the bumer.

X. Open the bumer valve and adjust the flame.

L\_gwAYS* Follow the procedures strictty.* Keep the chimney damper opened.* Keep the burning torch in front ofthe burner before opening the gas* Close the burner valve if the torch extinguishes.

Repeat the procedure again.GENERAL SHUTDOWN PROOEQURE FOR Fgegncgs' I. Close gas burner valves.

ll. Stop the air blowers.lll. Keep the chimney damper fully opened.IV. Close the isolation valve of the furnace.V. inject steamlhlitrogen in the gas main.

Vi. Blank the isolation point.

period. _Vlll. Ventitate the furnace properly.

ix Take samples from the isolated gas tine which should show

Oxygen minimum 20.6%Carbon Monoxide maximum 0.05 mglltr.ALMQ * FOLLOW THE SEQUENCE STRtCTLY.

* PURGE THROUGH END BLEEDERS.

Vll. Purge the header with etearnl‘N2 through the end bleeder for a suitable ’

* KEEP CHIMNEY DAMPER OPENED.

5. GUIDE LINES FOR PROTOCOL FOR GAS HAZAR@US WORK I

_ All gas line jobs should be done on a protocol in order to assign responsibilityand effective co-ordination among various agencies involved and also to provide checklistsfpoints to ensure that no important step is over looked. The format is as foliows :—

SHOPApprovedby

Heading :- (Write down the main heading for which the hazardous gas job is planned).

DATE:TlME :

A. Brief Description :- (Mention in short the necessity of the above job).

8. Special Condition Required ;- (Technological regime to be followed; e.g. gas linepressure reduction, local pressure reduction etc. and its implications to theplant).

C. Overali Coordinator of the job :-

S.NO. i DESCRIPTION )RE8PONS!BiLlTlES| - I (By Name)A. PREPARATORY JOBS :— (With names and designation of personsresponsible for Execution)

i)

ii)

iii)E3. ACTUAL JOBS :- (Details of operation in sequence with name and designation

of persons respcnsibielsection responsible).

5)ii)

iii)iv)C. SAFETY PRECAUTKDNS :- (Ail safety precautions including fire prevention &rescue steps taken).l) ?ii)iii)

SlGNATORiES :- Oral! the rsonsco nected fit 0 ‘to be mentioned here(with namgg. desiuna ton and eoanr'§r‘leR§. _

I

INDEX

8. No. Particulars Page No

1. Prooerties of gases 1 — 3

2. Gas Hazards 3 — 6

3. Gas Safety Rules 6 - 8

4. Safe system work procedure & 8 — 13protocol for gas hazardous gobs

5. Guide lines for protocol for gas 14 - 15hazardous work

6. General gas safety precautions 15 — 16required for gas line repair( isolated I Live lines )

7. Standard maintenance practices '16 - 18(SMP) for live 1‘ isolated gas lines

8. Gashnecomponmfisandfis 18-22

aooessofles

OTH

10.

11.

12.

13.

U5 6 :~

Drawings, sketches and other technical documents to be attached, wherevernecessary. #-

Check list for the safe execution of the gas job to be attached separately withthe protocol. It should include all the necessary check points related to the jobs

;.._.,and should be signed. (by all concerned) just before the start of the job. it would

help in counter checking all the activities so that no point is overlooked. ‘

GENERAL GAS SAFETY PRECAUTlON§ FOR GAS LINE REP-Alfl max

flSOLATED / LIVE LINES)

Fire brigade should be on stand by duty for live gas line repair jobs, and ifrequired for isolated gas line repairjob.

All live repair work should preferably be carried out in day light hours only.Safety appliances as prescribed by SEC) should be used by the working group.

During liftingipositioning of the cladslplpes, the nearby acoessoriesfpipelinesshould not be damaged. -

if required additional structural supports should be provided for the replacementof gas pipe lines in consultation with designer. -

All the lilting devices, slings, ropes etc. should be properly tested and ensuredbefore using them.

All the repair work shouid be carried out under proper guidance andsupervision.

All welding transformers should be property earthed and cable properly

V insulated.

No smoldering objects should be left at the work spot on stoppage of work. itshould be extinguished before leaving the spot.

Proper scafioidinglplatforrn should be made with escape route for carrying outthe job safely.

A protocol should be made for all gas line jobs, listing all the safety precautionsrequired for it. .

‘Clearance from gas safety to be taken for the start of work.

Open steam hose ShOUld be made available near the pO|I‘lt 01' WOFK.

14.15.16.

17..

For live line repair job, leakage arresting tools should be made available at thespot.

Welding cable joint should not touch nearby auxiliary lines.

Only experienced welders should be deployed for working on gas iines.

Oxygen and [).A. cylinders shouid be kept away so that whilecuttinglwelding spark should not fail on them.

STANDARD MAINTENANCE PRACTICES [EMF] F-‘QR LIVE I‘[8OI:fi[§Q

GAS LINE

is)‘ sMP's for isolated gas line

1.

10.

11.

Purge the isolated gas line from blank to end bleeder of line with steam Initrogen for sufficient time.

[After purging, open manholes, bieeders, end flanges as per sitecondition.

After thorough ventilation of line, take bieeder sample from inside the pipe linefrom -as many locations as possible and aiso test with expiosimeterf

if the sample is as per norm (Oxygen = 20.6%, C0 <==0.D5 mgflt), clearancecan be given for cuttinglwelding in the prescribed form. '

in case, cutting ofupipe line is planned water spraying should be done from thenearby manhole! or by cutting pocket where as for welding slight steam Initrogen should be kept on.

in bigger size of pipes (1500 die. and above) minimum one round Inside andtwo round outside welding should be ensured. While welding from inside. properventilation should be ensured.

As far as possible air circulation inside pipe line should be avoided by closingmanhoieslend flange 8: putting inert media during cuttingfwelding.

While welding new pipelcompensator with old pipe, the matching portion shouldbe free of any deposits.

During cuttinglwelding of gas line depending upon site conditions ettorts shouldbe made to remove muck from the gas line.

Cladding on isolated gas line should be done in presence of. inert media toavoid spontaneous combustion of deposits.

After the completion of repairrreplacement work of pipe line, ail opening shouldbe closed for leakage testing.

12.

‘l3

‘l4.

15.

16.

‘I7.

18.

‘I9.

20.

21.

22.

Gas line should be tested with steamlairfnltrogen. in case of nitrogenlair soapsolution should be applied and if steam is used it should be ensured that all

welded joints are coated with lime.

g..After.identlfication of leakages manholes near blank should be opened and

sample should be checked for leakage.

Re-welding of‘ defective portion should be done preferably in presence of inertmedia.

Retesting should be done after rectification of defect by following the previous

i mentioned methods.

If there is any interconnection of water drainer, breeders, steam connections andimpulse lines of two different gases, it should be isolated by inserting a blank

plate. -

Sampling should be carried out, while doing job near blank point.

if blanking is done before valve, the valve should be kept open to release thegas pocket between blank and gate. .

Cuttinglwelding and smoking by unauthorized persons should not be done nearisolated gas line.

Locallsed "l3LJND” can be formed with sandbagsfbricl-cs in order to keep thewater level maintained inside pipeline in case fire travels in gas lines.

While cutting pipe near blank, the isolating flanges should be welded in orderto prevent gas leakage due to release of pipe tension.

To provide support to auxiliary lines area sample should be checked.

lb) SMP's for live gas line

‘I .

if leakage is observed, it should be plugged and area sample should beensured for safe working.

Prepare half oladlpatch as per the profile of the gas line.

While welding on gas lines low current is preferred, so welding transformersshould be checked for proper regulation of current.

Pipe line thickness of defective area must be measured before the start of job,this ‘will help in arranging proper size of cladlpatchlelectrodes. Besides this, itwill also help in proper regulation of welding current.

Only experienced and trained welders should be allowed to work, as the line willbe in charged condition.

As the oas line is charoed-. lob should be done onlv durino dav Iioht hours.

10.

11.

12.

‘I3.

14.

15.

16.

'17’.

18.

19.

Cladfpatch should be properly positioned and welded without excessivehammering on gas line.As far as possible clad should be welded to the fully welded ribs.

Wher'e"ever possible saddle supports of gas lines should be temporarilysupported and then‘ saddle should be removed for welding of clads. After

complete welding of claols, saddle supports should be repositioned.

While positioning of clads at the temporarily plugged leakage point, steamnipple should be welded to the clads for supply of steam. This will help in

"avoiding fire. ~

if cladding is done at the spot where leakage is there, that particular spot should

' be completely welded to prevent the travel of gas to other clads.

As experienced, if more number of clads are tack welded gas travels from oneclad to another, therefore less number of clads should be first completelywelded and then others should be positioned.

Places where complete welding is not possible, clads should not be positioned.

Not less than two rounds of welding should be done on clads.

After the completion of job, all temporary supports should be removed andscrap should be properly stacked for disposal and disposed.

‘All welding/earthing connections should be removed from the spot on

completion of the work.Open steam hose should be made available near the place of work

Welding work on charged gas line should be done very cautiously and withoutany haste.

Welding transformer should preferably have the return cable lines.

COMPONENTS OF GAS LINE AND ITS ACCESSORIES

Like the arteries in human body, gas pipe lines are the vital energy carriers to

the various energy (Fuel) consuming units of a Steel Plant. As the choking of arteries inhuman body’ paralyses the complete system similarly improper maintenance of gas

network results in premature failure of gas line.

' The pipe line carrying gas to dilferent consumers is made up of mild steel quality

of thickness" 8-10 mm.. Gas line of dia. 1600 mm. And above shall be provided withstiffening ribs normally 3 metres apart. These stilfenirrg ribs takes care of circumferentialload on gas line caused due to gas pressure. These are also used for welding thesuboortsfor auxiliary vibes and walk wave alone the entire length of the pipe with hand

rails. For proper draining of water the slope of gas line towards the nearest

drain potshould 5 mm. Per metre length of the pipe.

Accessories of gas line :

CompensatorsWater drainers

Bleeders

isolating facilities

Butterfly valve

Orifice plate .Rupture disc I Pressure relief valve

9. Manholes & hand holes

10. End flanges lsteam I Nitrogen points

12. Flanges I Packings I Saddle supports etc.

13. Goggle Valves

_’‘~‘.C”.U‘.1=-S'-'°Nr*

1. COMPENSATOR5

These are installed on gas lines to take care of axial expansion and contractionof gas line. During the gas job these compensstcrs help in giving way for gap which isnecessary for manual insertion ltaking off of btank plate.

The following two type of cornpensators are generally used on gas lines :-

a) Slip joint or gland type compensator for Coke Oven gas line.13) Disc type compensator for Blast Furnace gas and Mixed gas line.

in disc type compensators drain valves should be provided at the bottomportion, for draining out condensate at regular intervals. This will improve the life of thecompensator.

2. warren crwueas

These are installed on gas line at the end of slope of the gas line or at locationwhere water accumulation is suspected. Minimum height of the water in the drain potshall exceed by 500 mm. Over the maximum working pressure. Also no water drainercondensate pipe line should be interconnected. Regular steaming of water drainer willprevent the choking of clrainers. ‘

Problems due to poor upkeep of water drains-rs are z»a) Gas leakage due to puncture in drainer body or its accessories.1)) Gas pressure fluctuation due to water accumulation.c) F-‘ast corrosion of gas line. '

3. BLEEDERS iThese are installed in gas line to discharge gas or steaminitrogen mixture

during charging or shutdown of gas lines. Their location depends upon the layout

of thegas line keeeine in view the era-oer charging/oureina of ass line. i

These shall be installed as per :-

A)

a) Selection of bleeder shall ensure 5 times discharge of the gasvolume in 10-30 min.. They shali be more than 19 mm. indiameter.

b) The bleeder shalt be located above the roof level more than 4metre. *

c) For inter plant pipe line the height of the bleeder on gas line shaltbe more than 4 metre from the gas pipe upper axis’. The exit pointof bieeder on gas line shail be at a height not less than 12 metresfrom the ground.

d) Bleeder pipes of different gases shall not be connected through acommon vent.

e) Design of the top of the bleeder shall protect against falling ofy atmospheric dust. The bleeder shall also have point for coilectionof gas samples.

ISOLATING FACiLlTlES

Gate Vaive :- These are used to isolate a certain portion of gas line from maingas iine. Regular greasing of spindle, protection of the same from the dust andrevisioning of valves during capital repair wit! keep the vaive in good workingcondition.

Maintenance tike cutting I welding on such gas line is done onty after the

menus! blanking I goggle valve turning by closing the gate valve.

3)

C)

Ggmgle yalve :- These are remote operated isolating valve. The closing of

‘ goggte valve ensure 100% isolation of gas line.

Advantages of goggle valve over gate valves are :~

1. 100% isolation of gas main.2. Spread of gas leakage for shorter duration.3. Very iess manpower is required.

"U” Seal :- This is the safest method for 100% isolation of gas line. By filling thewater in U—Seal to create a water column, the gas main is isolated in a veryshort duration. T

Advantages of U—Seal are :-

1. No gas realqage in atmos here.2-. 103 /o isolation of ass ltn -.

3. No moving parts, hence no maintenance. (Except formaintenance of water drainer)4. Very less manpower required to create water seal.

6. BUTTERFLY VALVE

These are used to regulate gas pressure in the gas line. They are eitherpneumatically or hydraulically operated. Over the period of time due to deposits in gaslines their operation becomes sluggish. During repair of gas lines cleaning of gas linewith steam and high pressure water takes away the deposits and valve operationbecome smooth.

6. ORIFICE PLATE

To measure the rate of gas flow in the gas line, orifice plates are installed. Toboth side of orifice plate impulse tapping is given to measure the difference in pressurewhich is converted by an instrument to measure flow and the same is displayed incubic metre per hour. During repair this impulse line should be disconnected frominstruments to prevent the steam entering and damaging the instruments. All impulselines on gas line should be separately steamed to clear choking. '

7. RUPTURE {DISC I PRESSURE RELIEF VALVE

Rupture disc are made up of 3 mm. Aluminium sheet, tightened between twoflanges and located after a gate valve. These disc ruptures shenever the pressure in thegas line exceeds a certain value or in case explosion this gives way for liberating theforce of explosion thus preventing the gas line and its equipments from damage.Whenever the disc ruptures the gate valve is immediately closed to stop the spread ofthe gas leakage.

The function of relief valve is same as that of rupture disc. A counter weight withpivot arrangement is given to release excess pressure on explosion. After its functioningthe counter weight seals the gas leakage.

The rupture disc and relief valve are located at places where no possibleexposure of gas to work man or any tire source is suspected. -

8. MANHOLES I HAND!-IOLES

Manhoies are given on gas line to facilitate work man to enter into the gas lineduring shut down and also for ventilation purpose. This can be also converted into agas line tapping by a special deblanking process. Manholes are generally located neargate valves, compensators or at locations where gas pocket can form.

Hand holes are given on bends and smaller dia. Pipe lines for cleaning, flushingand ventilation of gas line.

9. END FLANGES I STEAM I NITROGEN INSPECTION POINTS

End flanges as the name suggest are located at the end of gas line. These areopened during shut nlrawn for ventilation of ems: tine-

2'?

The steam I nitrogen points are given after every blanking location or at placeswhere gas pocket accumulation is suspected. These are used for purging the gas fromgas line.

10. FLANGES I PACKINGS I SADDLE SUPPORTS

Flanges are used with all type of isolating valves, butterfly valves, compensators,orifice plate etc.. After gate valve and goggle valve a separate isolating flanges shouldbe given for quick and safe isolation purpose. .

in gas line graphited asbestos rope packing or permanite packing is given toseal the gas leakage. This should be properly greased to prevent them from gettingdried up. White asbestos rope socked in salt water is used at places, which areexposed to high temperature.

Saddle supports are given after every isolating valve, compensator and atregular distances to support the gas line with Ferro concrete columns. The saddlesuppoits should be of roller type so that the gas line does not get damaged during gasjob or at times when gas line expand or contract linearly due to varying temperature.

.«.,-;-- - _.f,,‘,

PROGRAMME SCHEDULE

SESSIONS TOPiC

1

TIME

Steel Plant Gases andTheir properties

Gas Hazards

Safe system work procedure8. protocol for gas hazardous jobs

L U N C H B R E A KGas Safety Rules & SNIPS

Gas Line Maintenance

Group Discussion and Presentation

Summing up I Feed back

09:00 -10:30 AM. ‘

10:30 - 11 :45 AM.

11 :45 - 01:00 PM.

01:00 - 02:00 PM.

02:00 - 03:30 PM.

03:30 - 04:30 PM.

04:30 - 05:30 PM.

05:30 - 06:00 PM.

1 . PROPERWES OF GASES

Fuel gases having sufficient calorific value are used for heating purposes indifferent Furnaces, Stoves, Coke Oven Batteries etc.. The danger involved in handlingsuch gases are — Fire, Explosion and Gas poisoning. Improper handling of such gasesmay lead to hazardous conditions hampering the production flow and may also result in

loss of human life.

One should always remember that “GAS IS A GOOD SERVANT IF HANDLEDPROPERLY, BUTA BAD MASTER IF HANDLED IMPROPERLY".

SOME CAUSES OF GAS LINE ACCIDENTS

- - KENORANCE

- LACK OF SERIOUSNESS

- SLACKNESS 1N SUPERVISION

- IM PROPER COMMUMCATION

- OVER CONFIDENCE

- NON ADHERENCE TO THE LAID DOWN PROCEDURE

TYPICAL ANALYSIS *8: PROPERTIES OF THESE GASES ARE GIVEN BELOW:

..—:—:u_

CONSTITUENTS B.F.GAS COKE OVEN GAS L.D.GA$(“la By Volume) (“A By Volume) (% By Volume}

1. Carbon 27—30 6-7 65-67Monoxide (CO)

2. Carbon 9-1 5 243 ‘I 5-20Dioxide (CO2)

3. Hydrogen (H2) 1 .5-2 55-80 2-3

4. Methane (CH4) 0.3-0.5 25-28 ~

5. Nitrogen (N2) 55-58 6-8 15-20

6. Oxygen (O2) 0.5 0.3-0.5 —

PROPERTHES 2

BLAST FURNACE GAS I

heat and reducing gases. B.F.gas

B.Fce. 6.0. L.D.Explosive 40-70% 6—30°/o 20-70% (By Volume)I - - V: H; .Density 1.33 ll<g/n‘rn3 ' . U.46Kgl'Nm3_ , 1.37 l<grNm" ‘Calorific 800 l<.calrl\lm° 4300 l<.calll~lm° 1300 l<.calrNm"‘Value 'Very poisonous Slightly Poisonous, Deadly poisonousColourless Highly explosive, colourless, OdourlessOdourless Cclourless Typicalsmell of hydrogensulphide andNaphthalenel ems with _ Blue flame _ Yellow flame Blue flameHeavier than T Lighter than Heavier thanair air airSOURCES OF GASES :

E3.F.gas is generated in Blast Furnace where Coke is burnt to produce

contains 27-30% by volume of Carbon

Monoxide.

Workers engaged in the concerned areas can get exposed to its hazards. Following are

the gas hazardous areas where

B.F.gas may be present :-

a) Blast Furnace Cast House, Hoist House and Dust Catcherb) Stoves Area

:2) Blast Furnace Top

Cl) Gas Cleaning Plant

e) Gas Boosting Station

f) Areas close to B. F. gas lines and BF. gas equipments

such as drip pot, goggle valves etc.g) Consumer Deptts. 'COKE OVEN GAS 1

it is a byproduct of Coke Ovens and the percentage of Carbon

\a) Coke Oven cellarsb) Coke Oven top

Monoxide ranges from B to 7%. Following are the areas where this gas may be present

C) Old as weli as New By—Product PlantsMain Boosters and Exhauster HousesArea close to CO. gas lines, drip pot, goggle valves etc.Ail instrument control cabins in the Coke Oven and By-Product Piant) All GO. gas consumers in piant

\

ICONVERTOR GAS 1

This gas is generated at Converter Shop in the LD. Converter during theSteel Melting Process. it contains about 65 to 87% of Carbon Monoxide by volume. it isused after mixing with Coke Oven Gas. Following are the important areas where thisgas may be present.

a) Converter Shop :- l.D.Fan room, Valve changing station etc.b) L.D. Gas Holder

c) Entire Converter Gas piping and its accessories.

d) Gas Mixing and gas booster station.

2. GAS HAZARDS :

................_...-..-—.........—......-

F¥REEXPLOSIONGAS POISONING

Fire is a controiled burning reaction of gas mixture.Action to be taken in case of fire in Gas Main 2

i. if gas catches fire during work or through some crack, or because of

some leakage, it should be extinguished with ciay, steam, CO2extinguishers, water, Dry Chemical Powder etc. The portion of the gasmain should be ccoied down with water and only after the fire isextinguished, should the main valve be closed completely for carryingout repairs.ii. it should be remembered that the valve is not to be closed when tire isstill there and the pressure in the main should not go down below 100mmwc

THE TETRAHEDRON OF FIRE

Heat

Oxygen

Fuel

Chain of reaction

J—‘-.W!\7.—“

EXPLOSION

Explosion is a fast rate of reaction of explosive mixture releasing energy

form of sound,

in thepressure and heat.

The following two conditions can cause explosions 1»

ii.

The gas and air mixture must be within their explosive range.

The heat must be sufficient enough to ignite the resuitantrnixture ofgas and air. if the mixture of gas and air is below the "lower limit" orabove the "upper limit" of explosive range of gas or if the heat is not

sufficient to ignite the explosive mixture, obviously, there will be noexplosion.GAS LOWER EXFLOSIVE UPPER EXPLOSIVELiMiT OF GAS iii! LIMIT OF GAS INTHE MIXTURE THE MIXTURE(% By Volume) (% By Volume)

with resgect to air 'CARBON MONOXIDE 12.5 74.2METHANE 5 fl 5,__HYDROGEN 4 75ACETYLENE 2.5 92COKE OVEN 6 ' 30BLAST FURNACE 40 70CONVERTER 20 70L.P.(3. 1.9 9.5

CONDITIONS WHICH CAN CAUSE EXPLOSION

. . M The following

. . formation of an explosive mixture and causing explosion.

e"en¢e

operating conditions in handling gas are conducive to the

lrnproper purging of gas lines and equipment.

improper charging of a gas main.

Adopting the wrong procedures in lighting a furnace.

Esieeder discharging gas into a space where gas is likely to comecontact with a source of ignition.

ignoring the dead pockets (Trapped explosive mixture) in the shut oifgas lines.

Gradual and unexpected gas leakage from broken or crackedvalveslgas lines (specially coke ovens gas) into closed and semi—closedspaces which may include pockets under the furnace platforms,underground or overground galleries, or unauthorised sheds around ornear the furnaces.

Delay in applying ignition source while lighting up a furnace.

Leakage of unburnt gas into furnace

in to