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    ABB GroupJune 19, 2013 | Slide 1

    Periodic Hazard Review as anessential part of your PSM system

    Gerry Brennan, Lead Principal Consultant, ABB Consulting / Piper 25 Conference June 18-20 2013

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    Periodic Hazard Review as anessential part of your PSM system

    Contents

    Process Safety Management

    Need for periodic hazard review

    Techniques: HAZOP vs HAZID

    Learning points from experience ofperiodic hazard review

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    Process Safety versus Personal Safety

    Major

    Accident

    Hazards

    Slips, trips

    and falls

    Very

    Unlikely

    Possible

    ProcessSafety

    Personal

    Safety

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    What is Process Safety?

    The prevention of unplanned & uncontrolled loss of

    containment from plant and process equipment that

    might cause harm to people or the environment.

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    Learning

    phase

    Hardware wearout

    Loss of corporate memory

    Change in people

    Creeping Changes in plant

    Why is periodic hazard identification and risk analysis needed?

    HAZOP Ongoing risk assessment?

    Accident

    Life of Plant

    Plant

    Safety

    Performance

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    Objective for Periodic Hazard Review

    Evaluate controls for the hazards of the process as they

    are currently understood

    because

    Process changes have introduced new hazards

    New knowledge on hazard consequences is available

    Recent incidents have revealed new scenarios

    Barriers previously credited have changed

    ABB GroupJune 19, 2013 | Slide 7

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    HAZOP or HAZID?

    Loss of

    Containment

    FAULT TREEEVENT TREE

    HAZID

    CAUSES

    CONSEQ

    UENCES

    Mitigation

    Measures

    Prevention/Control

    Measures

    HAZOP

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    Methodology

    1. Split process into sections;

    HAZOP node is a process line

    HAZID node is unit operation, typically 1 or more P&IDs

    2. Describe design intent for node;

    operating parameters

    key aspects of process control system

    protective systems, trips/relief's/bunds

    3. Apply guidewords - can it happen?

    4. Assess consequences - does it matter?

    5. Assess design safeguards - are they adequate?

    6. Agree actions required to reduce risk

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    HAZOP Guidewords (IChemE)

    No (not, none)

    More (more of, higher)

    Less (less of, lower)

    As well as (more than)

    Part of

    Reverse

    Other than

    Earlier/later than

    With appropriate process parameter

    Flow

    Pressure

    Temperature

    Level

    Concentration

    Mixing

    Etc.

    Look for deviations from intent

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    HAZID Guidewords

    Burst Internal Explosion

    Overpressure

    Runaway Reaction

    Puncture

    Impact

    Weakening

    Corrosion

    Wear

    Temperature extreme

    Openings

    Vent/Drain

    Overflow

    Flange/Seal Look for causes of Loss of Containment

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    Comparison application to offshore installations

    Re-HAZOP of UK and overseas platforms during 2010-

    2013

    Hazard Study Equivalent days per platform: 90-150

    Recommendations for improvement: ~500

    HAZID of UK Platforms during 2011-13

    Hazard Study Equivalent days per platform: 15

    Recommendations for improvement: ~100

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    Learning Points fromexperience of periodichazard review

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    1. Write down clear Terms of Reference

    Scope of review; what is included/excluded

    Timescale; duration of commitment;

    Team leader; competence

    Hazard study team; essential disciplines

    Method; guidewords, recording detail, recording tool;

    stipulations about safeguards

    Time required; hours of work; how many days per week?

    Meeting room; lighting; space; projection; away from the

    installation Data Gathering; up to date PIDs, process information;

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    2. Specify the right team

    Leader

    Operations Manager Operator or Supervisor

    Process,

    Engineering /

    Maintenance

    Independent

    Team Member

    Other specialists as required

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    3. Choose process node carefully

    HAZOP: line or vessel HAZID: system by system

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    4. Correct level of detail in records

    Example of poor recording

    GW Cause Consequence Safeguard Recommendation

    No Flow Valve closed , etc Overpressure of Vessel XXXX Alarm and trip Consider pressure relief on

    Vessel xxxx

    Individual causesshould be

    detailed. Manualvalve HVxxx

    closed throughhuman error, ORFlow control

    failure FICxx, ORspurious closure

    XV xxx

    Sequence should bedeterminedTellthe Hazard story.No flow causing

    build up in pressurethis will be slow as

    feed is low at y

    m3

    /min.Overpressuremaximum up to 4xdesign, but as slowrate of pressure riseline leakage at 2 to3x design. Release

    of flammablesubstance into localprocess area. 1 to 2fatalities if ignitednormal occupancy.

    Separatesafeguards.

    Alarmresponse

    detailed. Trip

    tags andactions.

    Consider should beavoided. Should

    detail HAZOP teamconcernNormaldesign practice to

    have pressure relief.Should be a review

    to determine if reliefis required againstdesign requirements

    and protectionrequired to avoid

    fatalityconsequences.

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    5. Recording:Can Link Hazop to bow tie

    GW Cause Hazard Consequence Sev

    erity

    Safeguard L R Recommendation

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    6. Hazard Study Recommendations

    Need to carefully word to avoid confusion

    Person given action may not have been at the meeting

    Use what wherewhy format

    Add instructions for securing of double block and bleedisolations on the fuel gas supply line XYZ123 to theBurner 1-B-07 prior to maintenance into plant operatinginstruction 23, in order to protect against the flow of fuelinto the burner and risk of explosion at start-up

    Limit the number of actions generated

    Complete simple design checks before report is issued

    Keep a separate list of observations for project team

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    7. Hazard study followed by LOPA

    Hazard study provides the list of initial failuresand the risk screening to pick out significant

    hazard scenarios

    Layer of Protection Analysis (LOPA) provides

    a more detailed risk estimate

    Increasingly applied where there is a

    significant consequence or a Safety

    Instrumented Function

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    7 Cont: But there some points to bear in mind..

    Scope of LOPA: Only those with a SIF? Which severity level?

    If HAZOP records are sketchy, lengthy discussion in LOPA is likely

    Failure sequence not quantifiable: Must be an equipment or human failure

    Poor: Operator error

    Good: Block valves HV1 and HV2 left closed after maintenance

    Poor logic in HAZOP: e.g. failure of a safeguard as cause

    Failure to determine ultimate consequence and hence all safeguards

    SIF cant be identified as no tag number on HAZOP record

    Also other safeguards, e.g. alarms, procedures, relief systems

    LOPA is top down from hazardous event, HAZOP is bottom up from cause

    Need to cross reference all causes in HAZOP record

    ABB GroupJune 19, 2013 | Slide 21

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    8. Evergreen Records and revalidation programmes

    Goals:

    Accurate, current, detailed description of hazards and

    safeguards available for reference in ORAs, MOCs

    Reduce resources demanded for periodic process

    hazard review Method:

    Update the periodic review record with

    Recommendations Closures and risk assessment

    results (such as LOPA);

    Revalidate the periodic review of hazards, every 5

    years

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    8 Cont.: Revalidation Method

    Select first node

    Ask the following questions

    Have all the recommendations been completed?

    Have the changes since the baseline Hazard Study been fully assessed?

    Have there been any relevant process safety incidents, has the learning

    from these been acted upon?

    Are there any current concerns?

    Is there any new knowledge or relevant good practice applicable to this

    node?

    In view of the above, does the hazard study need repeating? Repeat over all nodes

    Table updated and new recommendations in the revalidation report

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    ABB GroupJune 19, 2013 | Slide 24 ABB GroupJune 19, 2013 | Slide 24