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HAZOP STUDY 
HAZard and OPerability 
An introduction
Content 
 History 
 Purpose 
 Hazards 
 Deviations 
 Parameters 
 Guidewords 
 Consequences 
 Safeguards 
 Applic...
Origins of HAZOP 
 Concept dreamed up by Bert Lawley at I.C.I. 
in the late 1960’s 
 Result of a desire to have structur...
HAZOP in the 1980’s 
 U.K. HSE and the Dutch Arbeidsinspectie 
began to mandate HAZOP as part of Safety 
Report for “Seve...
Purpose of HAZOP 
 To identify credible causes, consequences 
and safeguards before INCIDENTS occur 
 To define recommen...
Scope of HAZOP 
 Review is limited to the piping, 
instrumentation and equipment shown on 
the P&ID’s (do not re-design) ...
HAZARDS 
 Fire and Explosion 
 Reactive Chemicals Incidents 
 Toxic Exposure 
 Corrosion 
 Radiation 
 Vibration 
 ...
“Deviations” 
 Hazards are caused by DEVIATIONS 
from the DESIGN INTENTION 
 HAZOP is a method for generating 
these “DE...
Study is based on 
“PARAMETERS” 
 Flow 
 Temperature 
 Pressure 
 Level 
 Composition 
 Agitation 
 Anything it is ...
In combination with “GUIDE 
WORDS” 
 “No” 
 “Less” 
 “More” 
 “Reverse” 
 “Instead of ” or “Other than” (e.g. 
someth...
Combinations of parameters and 
guide words are “DEVIATIONS” 
 No flow 
 Less flow 
 More flow 
 Reverse flow 
 Flow ...
Deviations are logical 
combinations like... 
 More temperature 
 Less pressure 
Ignore illogical combinations like…. 
X...
Determining the causes for a 
deviation 
 Consider only the causes that originate within the node 
(consequences may be o...
Consequences 
 Describe all consequences, even those that propagate outside 
the node. 
 Consequences may include: 
 Pe...
Safeguards 
 Safeguards may include: 
 Equipment design 
 Instrumentation (control, alarm and shutdown) 
 Pressure rel...
What can HAZOP be applied 
to? 
 Continuous processes 
 Batch processes 
 Operating procedures 
 Maintenance procedure...
Recommendations 
 Recommendations are made to: 
 Eliminate a cause 
 Prevent or mitigate the consequence 
 Reduce the ...
HAZOP Process 
Team maximum 6 persons from (example): 
 run plant engineer 
 programmer 
 process control 
 process ch...
Nodes 
 P&ID’s for the process are broken into manageable 
sections called nodes 
 Nodes generally consists of unit oper...
Typical nodes 
E 201 
R 201 
P 201 
NODE 1 
NODE 2 
Oct. 3, 2013 Risk Management 20
Nodes 
 There is no “right” way to define nodes 
 Usually start with a small node 
 As experience builds, move to a lar...
Starting the study: 
 The most knowledgeable person describes 
the INTENTION of the node 
 Composition (which chemicals ...
Start with Deviation “No Flow” 
 Team gives all the causes for no flow in the 
lines and equipment inside the node 
 Lea...
Team decision on “ACTION” 
column 
 Team may decide if any new action is 
needed 
 Can record any protective devices or ...
After “no flow” 
 Repeat exercise for “less flow” 
(usually similar to “no flow” 
 Repeat exercise for “more flow” 
 Re...
After “flow” 
 List causes for “more temperature” 
 proceed to consequences for “more 
temperature” 
 repeat all steps ...
When parameters are all done 
for node 1 
 Repeat whole process for node 2 
 And all the other nodes defined in the 
stu...
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Presentation hazop introduction

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Presentation hazop introduction

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Presentation hazop introduction

  1. 1. HAZOP STUDY HAZard and OPerability An introduction
  2. 2. Content  History  Purpose  Hazards  Deviations  Parameters  Guidewords  Consequences  Safeguards  Application  HAZOP in Dow  HAZOP Process  Nodes  Starting the Study Oct. 3, 2013 Risk Management 2
  3. 3. Origins of HAZOP  Concept dreamed up by Bert Lawley at I.C.I. in the late 1960’s  Result of a desire to have structured check on P. & I.D.s  Spread through I.C.I. in early 1970’s  Endorsed by the “Health and Safety Directorate” of the U.K. government  NL, Belgian and U.K. etc. governments have adopted HAZOP Oct. 3, 2013 Risk Management 3
  4. 4. HAZOP in the 1980’s  U.K. HSE and the Dutch Arbeidsinspectie began to mandate HAZOP as part of Safety Report for “Seveso Directive”  I.C.I. by this time were doing HAZOP on “everything”  Dow incorporated in its Risk Management process based on its own criteria (focusing on highest risk) Oct. 3, 2013 Risk Management 4
  5. 5. Purpose of HAZOP  To identify credible causes, consequences and safeguards before INCIDENTS occur  To define recommendations to minimize the HAZARD by eliminating or controlling the cause or providing “lines of defence”  Provide compatible information for subsequent Process Safety efforts (i.e. LOPA scenarios)  Comply with regulatory Process Safety requirements Oct. 3, 2013 Risk Management 5
  6. 6. Scope of HAZOP  Review is limited to the piping, instrumentation and equipment shown on the P&ID’s (do not re-design)  Review is limited to deviations from normal operations  Impact of process unit on the utility systems or other process units will be noted as requiring further study  Primary intent is to identify hazards and define action items for additional safeguards if appropriate Oct. 3, 2013 Risk Management 6
  7. 7. HAZARDS  Fire and Explosion  Reactive Chemicals Incidents  Toxic Exposure  Corrosion  Radiation  Vibration  Mechanical Hazards Oct. 3, 2013 Risk Management 7
  8. 8. “Deviations”  Hazards are caused by DEVIATIONS from the DESIGN INTENTION  HAZOP is a method for generating these “DEVIATIONS” using “GUIDE WORDS” Oct. 3, 2013 Risk Management 8
  9. 9. Study is based on “PARAMETERS”  Flow  Temperature  Pressure  Level  Composition  Agitation  Anything it is important to control Oct. 3, 2013 Risk Management 9
  10. 10. In combination with “GUIDE WORDS”  “No”  “Less”  “More”  “Reverse”  “Instead of ” or “Other than” (e.g. something else or wrong composition) Oct. 3, 2013 Risk Management 10
  11. 11. Combinations of parameters and guide words are “DEVIATIONS”  No flow  Less flow  More flow  Reverse flow  Flow of something not planned  More temperature  Less temperature  And so on…... Oct. 3, 2013 Risk Management 11
  12. 12. Deviations are logical combinations like...  More temperature  Less pressure Ignore illogical combinations like…. X Reverse temperature Oct. 3, 2013 Risk Management 12
  13. 13. Determining the causes for a deviation  Consider only the causes that originate within the node (consequences may be outside of the node)  Deviations could be caused by:  Equipment or process control failure  Human error  Loss of utilities  External events such as fire  Long term processes, e.g. erosion, corrosion, coking  If process instrumentation crosses a node boundary, control malfunction is considered a cause in both nodes  Deviations that require the simultaneous occurrence of two or more unrelated causes are not considered Oct. 3, 2013 Risk Management 13
  14. 14. Consequences  Describe all consequences, even those that propagate outside the node.  Consequences may include:  Personnel injury  Environmental damage  Equipment damage  Property loss  Extended downtime  Operability/Quality problems  Consequences are described assuming there are no safeguards  Describe consequences as a chronological sequence of events Oct. 3, 2013 Risk Management 14
  15. 15. Safeguards  Safeguards may include:  Equipment design  Instrumentation (control, alarm and shutdown)  Pressure relief devices  Administrative procedures  Only list those instrument systems that have at least an alarm as a safeguard  Control instrumentation must automatically correct or mitigate a process deviation  Operator training and administrative procedures should be listed provided they are part of ODMS Oct. 3, 2013 Risk Management 15
  16. 16. What can HAZOP be applied to?  Continuous processes  Batch processes  Operating procedures  Maintenance procedures  Any operation where the Design Intention is defined and deviations are possible Oct. 3, 2013 Risk Management 16
  17. 17. Recommendations  Recommendations are made to:  Eliminate a cause  Prevent or mitigate the consequence  Reduce the likelyhood that the hazard will occur  Examples of recommendations include:  Equipment/instrumentation changes/additions  Further study needed  Inspection and maintenance  Training  Administrative systems to manage hazards  Verification of design assumptions Oct. 3, 2013 Risk Management 17
  18. 18. HAZOP Process Team maximum 6 persons from (example):  run plant engineer  programmer  process control  process chemist  shift operations team member  study leader/facilitator Oct. 3, 2013 Risk Management 18
  19. 19. Nodes  P&ID’s for the process are broken into manageable sections called nodes  Nodes generally consists of unit operations and associated piping and connect to upstream and downstream units  Nodes are defined by the HAZOP team and can be redefined as needed  A “Global issues” node can be included to capture hazardous events that can impact the entire process unit. For example: Loss of containment Sampling Utility failure Oct. 3, 2013 Risk Management 19
  20. 20. Typical nodes E 201 R 201 P 201 NODE 1 NODE 2 Oct. 3, 2013 Risk Management 20
  21. 21. Nodes  There is no “right” way to define nodes  Usually start with a small node  As experience builds, move to a larger node  Follow the leader’s intuition  If the team gets bored, the node is probably too small  If the team gets confused, the node is probably too big Oct. 3, 2013 Risk Management 21
  22. 22. Starting the study:  The most knowledgeable person describes the INTENTION of the node  Composition (which chemicals are in the equipment)  Flow, temperature, pressure, phase, quantity, agitation etc  …. Anything important to the process  Leader records for study team reference Oct. 3, 2013 Risk Management 22
  23. 23. Start with Deviation “No Flow”  Team gives all the causes for no flow in the lines and equipment inside the node  Leader prompts their thinking  Team can add but not delete  These causes are recorded in software package  The library in the software can be consulted for possible additional causes  When the ideas “dry up” move on to CONSEQUENCES Oct. 3, 2013 Risk Management 23
  24. 24. Team decision on “ACTION” column  Team may decide if any new action is needed  Can record any protective devices or alarms which become active e.g. PSV’s  Can refer decision outside the team  Can refer serious consequences for “consequence analysis”  MUST NOT REDESIGN THE PLANT in the Hazop study session!! Oct. 3, 2013 Risk Management 24
  25. 25. After “no flow”  Repeat exercise for “less flow” (usually similar to “no flow”  Repeat exercise for “more flow”  Repeat exercise for “reverse flow”  Repeat exercise for “composition” (other than expected material composition)  UNTIL “FLOW” is completely studied Oct. 3, 2013 Risk Management 25
  26. 26. After “flow”  List causes for “more temperature”  proceed to consequences for “more temperature”  repeat all steps as for flow  when temperature is studied, go to pressure  after pressure, consider other parameters, e.g. agitation (use design intention as a guide) Oct. 3, 2013 Risk Management 26
  27. 27. When parameters are all done for node 1  Repeat whole process for node 2  And all the other nodes defined in the study scope  List actions and responsibility for follow up Oct. 3, 2013 Risk Management 27

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