Presentation hazop introduction

1. HAZOP STUDY
HAZard and OPerability
An introduction

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. 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. 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. 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. 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. HAZARDS
 Fire and Explosion
 Reactive Chemicals Incidents
 Toxic Exposure
 Corrosion
 Radiation
 Vibration
 Mechanical Hazards
Oct. 3, 2013 Risk Management 7

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. Study is based on
“PARAMETERS”
 Flow
 Temperature
 Pressure
 Level
 Composition
 Agitation
 Anything it is important to control
Oct. 3, 2013 Risk Management 9

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. 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. Deviations are logical
combinations like...
 More temperature
 Less pressure
Ignore illogical combinations like….
X Reverse temperature
Oct. 3, 2013 Risk Management 12

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. 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. 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. 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. 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. 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. 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. Typical nodes
E 201
R 201
P 201
NODE 1
NODE 2
Oct. 3, 2013 Risk Management 20

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. 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. 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. 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. 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. 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. 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