What is a HAZOP? by E72asoA

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   2005              CSChE-PSM Division (Hazard Identification: HAZOPs)                      1
   Hazard Identification - Hazard
     and Operability studies
             (HAZOP)
         William Anderson (University of Waterloo)
         Frank Collins (University of New Brunswick)
         Aaron Phoenix (University of Saskatchewan)

   Acknowledgements:
   Marvin Rausand (Norwegian University of Science and Technology)
   Steve Coe (Irving Oil Limited)
   Dyadem International Ltd.

2005            CSChE-PSM Division (Hazard Identification: HAZOPs)   2
Risk Management’s First Step:
admit there’s a problem!
                                 Determine Risk
                                     Review
                                  Requirements
McCutcheon -

                                    Identify
                                    Hazards


          Reduce                     Assess
           Risk                       Risk

                 Yes
        Can the risk     No         Is the risk
        be reduced?                 tolerable?
                                              Yes
                                                               To assess risk we must
          No
                                                               first identify the
                                     Manage                    hazards:
       Discontinue
                                     Residual
         Activity
                                       Risk                    Look DOWN !
                                                               Ask Questions!

2005               CSChE-PSM Division (Hazard Identification: HAZOPs)                   3
       Hazards Identification: HAZOPs
       A Hazard and Operability (HAZOP) study is a structured and
       systematic examination of a planned or existing process or
       operation in order to identify and evaluate problems that may
       represent risks to personnel or equipment, or prevent efficient
       operation.                                           - Rausand

       • an integral part of any design
       strategy or process safety
       management plan.
       • a qualitative cause-effect analysis
       made by engineering team
       • one of several systematic
       identification techniques: “What-If
       “Analysis, Dow F&EI or CEI, FMEA,
       etc..
       • each company may adopt their own
       preferred HAZOP methodology.


2005               CSChE-PSM Division (Hazard Identification: HAZOPs)    4
 HAZOP - History

  •The basis for HAZOP was laid by ICI (Imperial Chemical Industries) in
  1963 and was based on so-called “critical examination” techniques

  • First guide: “A Guide to Hazard and Operability Studies”, ICI
  and Chemical Industries Associations Ltd. 1977.

  • First main textbook: Kletz, T. A.: “Hazop and Hazan -
  Identifying and Assessing Process Industry Hazards”,
  Institution of Chemical Engineers.

  • originally developed for chemical process industries – now extended to
  many industries, and can even include procedures.




2005            CSChE-PSM Division (Hazard Identification: HAZOPs)           5
When should you perform a HAZOP?
• inherent safety is included at the earliest possible stage of design; HAZOPs are
typically conducted any time after a design flow sheet is considered functional:
         • during conceptual design (after plant layout drawings)
         • during detailed design (after complete P&IDs)
         • during definitive design (before capital expenditure)
         • during construction/commissioning
         • during normal operations


Generally: any significant design or operational change should trigger a hazard
identification procedure.




2005           CSChE-PSM Division (Hazard Identification: HAZOPs)              6
Types of HAZOP Studies:
 Process HAZOP
 The original HAZOP technique was developed to assess
 plants and process systems
 Human HAZOP
 A “family” of specialized HAZOPs. More focused on
 human errors than technical failures
 Procedure HAZOP
 Review of procedures or operational sequences
 Sometimes denoted SAFOP - SAFe Operation Study
 Software HAZOP
 Identification of possible errors in the development of
 software
                                                                    - Rausand




  Only Process HAZOPs will be covered in this presentation


2005           CSChE-PSM Division (Hazard Identification: HAZOPs)               7
       The HAZOP Team and Meetings




2005      CSChE-PSM Division (Hazard Identification: HAZOPs)   8
Process HAZOP Team - Organization
                                   Team Leader – “Facilitator”


                             HAZOP Secretary




       Project Engineer      Safety Engineer        Electrical I/C Engineer   Process Engineer



           Engineering Manager                                      Environmental Manager


Other possible team members:
- Operators
- Maintenance Supervisors
- equipment vendors
- technologists/technicians as required                                Need people who
                                                                    understand the process
2005                CSChE-PSM Division (Hazard Identification: HAZOPs)                           9
Process HAZOP Team - Responsibilities
   HAZOP team leader

   • Define the scope for the analysis
   • Select HAZOP team members
   • Plan and prepare the study
   • Chair the HAZOP meetings
        • Trigger the discussion using guide-words and parameters
        • Follow up progress according to schedule/agenda
        • Ensure completeness of the analysis

   The team leader should be independent (i.e., no responsibility
   for the process and/or the performance of operations)




2005          CSChE-PSM Division (Hazard Identification: HAZOPs)    10
Process HAZOP Team - Responsibilities
  HAZOP Secretary
  – Prepare HAZOP work-sheets
  – Record the discussion in the HAZOP
  meetings
  – Prepare draft report(s)


                                     HAZOP Team Member
                                     - Be active! Everybody’s contribution is
                                     important
                                     - Be to the point. Avoid endless discussion
                                     of details
                                     - Be critical in a positive way - not negative,
                                     but constructive
                                     -Be responsible. He who knows should let
                                     the others know
                                     - remember purpose is to identify hazards!
                                     (don’t try to solve the problem)
2005          CSChE-PSM Division (Hazard Identification: HAZOPs)                  11
Process HAZOP - Meetings
Proposed agenda:

1. Introduction and presentation of participants
2. Overall presentation of the system/operation to be analyzed
3. Description of the HAZOP approach
4. Presentation of the first node or logical part of the operation
5. Analyze the first node/part using the guide-words and parameters
6. Continue presentation and analysis (steps 4 and 5)
7. Summarize findings

Focus should be on potential hazards as well as potential
operational problems during:
         - normal operation
         - start-up and shut down
         - emergency situations



2005           CSChE-PSM Division (Hazard Identification: HAZOPs)     12
Process HAZOP - Pre-requisites
Before meeting, the Team should assemble:
                                                   • process flow diagrams
                                                   • process P&IDs
                                                   • plant layout drawings
                                                   • material and energy balances
                                                   • operation manuals/procedure
                                                   sheets
                                                   • MSDS on all materials used or
                                                   produced
                                                   • Plant Safety Manual
                                                   • Code and Standard
                                                   Handbooks

2005         CSChE-PSM Division (Hazard Identification: HAZOPs)                13
       Process HAZOP - Procedure




2005     CSChE-PSM Division (Hazard Identification: HAZOPs)   14
                      Divide process into
                        logical nodes
                                                    Process HAZOP
                                                      Procedure
                      Select study node


                                                    Apply deviation “guide
                        Select process                word” to parameter,
                          parameter                  identify hazards and
                                                       document actions
         yes                     yes


   Additional
                 no       Additional         no          Additional          yes
 nodes on flow            parameters                     guide words
    sheet?                applicable?                    applicable?


         no
                       Prepare HAZOP Report
2005             CSChE-PSM Division (Hazard Identification: HAZOPs)                15
Process HAZOP – Worksheets
•   Findings recorded at meeting on “HAZOP worksheets”
•   Worksheets take various forms (company dependent)
•   General Column Headings:

             1. Study node
             2. Parameter
             2. Guide-word
             3. Possible causes
             5. Consequences
             6. Risk Matrix (Severity x Likelihood = Relative Risk)*
             7. Safeguards
             8. Actions required (or, recommendations)
             9. Actions allocated to (follow-up responsibility)
             10. Status (complete, incomplete, pending)
*optional – an internal ranking system for prioritization (severity and
likelihood generally given a number between 1-4)


2005            CSChE-PSM Division (Hazard Identification: HAZOPs)        16
 Process HAZOP – Worksheets
Company:                                      HAZOP Team:
Process:                                      Drawing #                                      Date:
Section:                                      Operation Mode:                                Page:                    of




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  Study     Process    Guide                      Possible




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  Node     Parameter   Word Possible Causes     Consequences        Risk        Safeguards   Recommendations                   Status
                                                                S    L     RR




   The HAZOP Team                                               It is also very important to
   members should be                                            indicate the mode of
   identified, as well as                                       operation upon which the
   the flow sheet upon                                          assessment is made: normal
   which the assessment                                         operation, start-up, shutdown,
   is based.                                                    emergency


 2005                      CSChE-PSM Division (Hazard Identification: HAZOPs)                                                       17
 Process HAZOP – Worksheets
Company:                                      HAZOP Team:
Process:                                      Drawing #                                      Date:
Section:                                      Operation Mode:                                Page:                    of




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  Node     Parameter   Word Possible Causes     Consequences        Risk        Safeguards   Recommendations                   Status
                                                                S    L     RR




Node
A node is a specific piece of process equipment that is to be evaluated for
deviations from its design intent. Examples might be: separators, heat
exchangers, scrubbers, pumps, compressors, and interconnecting pipes
with equipment.




 2005                      CSChE-PSM Division (Hazard Identification: HAZOPs)                                                       18
Process HAZOP – Worksheets
   Selecting Nodes

       In dividing up the flow sheet into nodes, it is good practice to:

       •   Move with the flow of material through the process (start at the
           material entry point of flow sheet and move through units as you
           encounter them). This will avoid overlap of deviations.
       •   Proceed, if possible, through the first major piece of equipment
           and stop when you reach the fitting of the next major piece of
           equipment.
       •   Include, if possible, all instrumentation and control elements that
           feed back or forward to the node.
       •   avoid more than one large unit operation in a node. Large nodes
           may complicate the analysis.



2005             CSChE-PSM Division (Hazard Identification: HAZOPs)              19
 Process HAZOP – Worksheets
Company:                                      HAZOP Team:
Process:                                      Drawing #                                      Date:
Section:                                      Operation Mode:                                Page:                    of




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  Node     Parameter   Word Possible Causes     Consequences        Risk        Safeguards   Recommendations                   Status
                                                                S    L     RR




Parameter
The relevant parameter for the condition(s) of the process
(e.g. temperature, pressure, flow, composition, etc..).




 2005                      CSChE-PSM Division (Hazard Identification: HAZOPs)                                                       20
Process HAZOP – Worksheets
Typical Process Parameters




2005       CSChE-PSM Division (Hazard Identification: HAZOPs)   21
 Process HAZOP – Worksheets
Company:                                      HAZOP Team:
Process:                                      Drawing #                                      Date:
Section:                                      Operation Mode:                                Page:                    of




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  Node     Parameter   Word Possible Causes     Consequences        Risk        Safeguards   Recommendations                   Status
                                                                S    L     RR




Guide-word
A short word to create a deviation of the design/process intent. The most
commonly used set of guide-words is: no, more, less, as well as, part of,
other than, and reverse.




 2005                      CSChE-PSM Division (Hazard Identification: HAZOPs)                                                       22
Process HAZOP – Worksheets




2005   CSChE-PSM Division (Hazard Identification: HAZOPs)   23
Process HAZOP – Worksheets

 Additional Guide Words (ones that may be useful during start-
 up/shutdown or emergency situations):




2005         CSChE-PSM Division (Hazard Identification: HAZOPs)   24
 Process HAZOP – Worksheets
Company:                                      HAZOP Team:
Process:                                      Drawing #                                      Date:
Section:                                      Operation Mode:                                Page:                    of




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  Node     Parameter   Word Possible Causes     Consequences        Risk        Safeguards   Recommendations                   Status
                                                                S    L     RR




Possible Causes
Any and all reasons why the deviation could occur. It is often
recommended to start with the causes that may result in the
worst possible consequence.

                              Deviation = Guide Word + Parameter



 2005                      CSChE-PSM Division (Hazard Identification: HAZOPs)                                                       25
Process HAZOP – Worksheets
Possible Causes: there can be many for one deviation...

Deviation: NO FLOW
         Possible Causes: Wrong flow path - blockage - incorrect
         slip plate – incorrectly fitted return valve - burst pipe - large
         leak - equipment failure - incorrect pressure differential -
         isolation in error
Deviation: MORE FLOW
         Possible Causes: Increase pumping capacity - increased
         suction pressure -reduced delivery head - greater fluid
         density – exchanger tube leaks - cross connection of systems -
         control faults
Deviation: MORE TEMPERATURE
         Possible Causes: Ambient conditions - failed exchanger
         tubes - fire situation -cooling water failure - defective control -
         internal fires


2005             CSChE-PSM Division (Hazard Identification: HAZOPs)            26
 Process HAZOP – Worksheets
Company:                                      HAZOP Team:
Process:                                      Drawing #                                      Date:
Section:                                      Operation Mode:                                Page:                    of




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  Node     Parameter   Word Possible Causes     Consequences        Risk        Safeguards   Recommendations                   Status
                                                                S    L     RR




Possible Consequence
The result of the deviation, if it occurs. Consequences may be as simple as
a decrease in quality, or as complicated as an influence on process control.

There are often multiple consequences to one deviation.




 2005                      CSChE-PSM Division (Hazard Identification: HAZOPs)                                                       27
 Process HAZOP – Worksheets
Company:                                      HAZOP Team:
Process:                                      Drawing #                                      Date:
Section:                                      Operation Mode:                                Page:                    of




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  Node     Parameter   Word Possible Causes     Consequences        Risk        Safeguards   Recommendations                   Status
                                                                S    L     RR




Risk Matrix
A risk ranking scheme that allows for prioritization. It forms a relative weighting of hazards
based upon:
S=Severity - usually a number from 1-4 based upon magnitude of catastrophe of the
deviation.
L=Likelihood - usually a number from 1-4, based upon perceived probability and/or
recorded data supporting the probability of the deviation
RR=Relative Risk – the multiple result of S x L, used for relative ranking at the end of the
HAZOP process.

 2005                      CSChE-PSM Division (Hazard Identification: HAZOPs)                                                       28
Process HAZOP – Worksheets
Risk Matrix example:
                 Number of Consequences by Severity and Likelihood (Risk Matrix)




2005          CSChE-PSM Division (Hazard Identification: HAZOPs)                   29
 Process HAZOP – Worksheets
Company:                                      HAZOP Team:
Process:                                      Drawing #                                      Date:
Section:                                      Operation Mode:                                Page:                    of




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  Node     Parameter   Word Possible Causes     Consequences        Risk        Safeguards   Recommendations                   Status
                                                                S    L     RR




Safeguards
Facilities that help to reduce the frequency of the deviation or to mitigate its
consequences. For example:
          - pressure relief valves (PRVs)
          - gas leak detectors
          - level switches
          - control strategies
          - inerted environments

 2005                      CSChE-PSM Division (Hazard Identification: HAZOPs)                                                       30
 Process HAZOP – Worksheets
Company:                                      HAZOP Team:
Process:                                      Drawing #                                      Date:
Section:                                      Operation Mode:                                Page:                    of




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  Node     Parameter   Word Possible Causes     Consequences        Risk        Safeguards   Recommendations                   Status
                                                                S    L     RR




 Recommendations
 Actions that are suggested to mitigate the risk. These may include:

                - alterations to the design approach
                - addition/deletion of equipment in P&ID
                - addition of instrumentation
                - revision of control philosophy
                - establishing new maintenance procedures
                - recommendation for quantitative risk assessment

 2005                      CSChE-PSM Division (Hazard Identification: HAZOPs)                                                       31
 Process HAZOP – Worksheets
Company:                                      HAZOP Team:
Process:                                      Drawing #                                      Date:
Section:                                      Operation Mode:                                Page:                    of




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  Node     Parameter   Word Possible Causes     Consequences        Risk        Safeguards   Recommendations                   Status
                                                                S    L     RR




 Responsibility
 HAZOP Team Member who will initiate recommended action
 Reply Date
 Date to complete assigned action
 Status
 complete, incomplete, pending (further data required)



 2005                      CSChE-PSM Division (Hazard Identification: HAZOPs)                                                       32
       Process HAZOP – Reporting




2005     CSChE-PSM Division (Hazard Identification: HAZOPs)   33
Process HAZOP - Report
Typical Format:

1. Introduction
2. System description
3. Documents (on which the analysis is
   based)
4. Methodology
5. Team members
6. HAZOP results
   – Reporting principles
   – Classification of recordings
   – Main results
Appendix 1: HAZOP work-sheets
Appendix 2: P&IDs (marked)



2005          CSChE-PSM Division (Hazard Identification: HAZOPs)   34
Process HAZOP – Review Meeting

                           Review meetings should be arranged to
                           monitor completion of agreed actions that
                           have been recorded. The review meeting
                           should involve the whole HAZOP team. A
                           summary of actions should be noted and
                           their status classified as:

                                • complete
                                • incomplete
                                • pending further information




2005   CSChE-PSM Division (Hazard Identification: HAZOPs)              35
HAZOP - Summary
Results:
• Improvement of system or operations
         - Reduced risk and better
           contingency
         - More efficient operations
• Improvement of procedures
• General safety awareness developed
   between disciplines on process
• strong team building exercise

Advantages:
• completeness: covers design and
operations
• excellent screening exercise for
quantitative risk analysis
• structured format forces participants to
think “outside-the-box”


2005             CSChE-PSM Division (Hazard Identification: HAZOPs)   36
HAZOP - Summary
Pitfalls:
• defensive team members
• “no problem”
• diverted discussions (can be time-
consuming exercise)
• participants focus too much on
solutions
                                               Success Factors:
                                               • Company commitment to PHA
                                                  exercise
                                               • Accuracy of drawings and data
                                               • Experienced, independent, strong
                                                  Team Leader
                                               • Skilled, knowledgeable Team
                                                  Members
                                               • Co-operation of Team
                                               • Focus on goal: identify hazards
2005              CSChE-PSM Division (Hazard Identification: HAZOPs)                37
             HAZOP – References
  1. EC61882. “Hazard and operability studies (HAZOP
      studies) – Application guide”. International Electrotechnical
      Commission, Geneva.
  2. Crawley, F., M. Preston, and B. Tyler: “HAZOP: Guide to
      best practice. Guidelines to best practice for the process and
      chemical industries”. European Process Safety Centre and
      Institution of Chemical Engineers, 2000
  3. Kyriakdis, I.: “HAZOP - Comprehensive Guide to HAZOP in
      CSIRO”, CSIRO Minerals, National Safety Council of
      Australia, 2003
  4. Kletz, T. A.: “Hazop – past and future”. Reliability
      Engineering and System Safety, 55:263-266, 1997.
  5. Rausand, M. and Hoyland, A: “System Reliability Theory: Models Statistical
      Methods and Applications”, 2nd Ed., Wiley, 2003
  6. Crowl, D and Louvar, J.: “Chemical Process Safety”, 2nd Ed., Prentice- Hall, 2002
  7. Wilson, L and McCutcheon, D: “Industrial Safety and Risk Management”,
      University of Alberta Press, 2003




2005             CSChE-PSM Division (Hazard Identification: HAZOPs)                      38

								
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