pha training presentation
TRANSCRIPT
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Process Hazards Analysis
Process Safety
InformationProcess Hazard Analysis
By : MSd
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Philosophy
ECPL believes that Process hazardsanalysis (PHAs) shall be conducted on
regular basis to Identify, Evaluate and
Develop methods to control significant
hazards associated with Highly Hazardous
Processes (HHP) and Lower Hazard
Operations (LHO).
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Process Hazard Analysis Concept
PHA is a Methodical Study Approach used toExamine :
Each new or
Existing facility
To assure that hazards of "catastrophic and major"Safety or Environmental Consequences are:
Identified and
Adequately controlled to an acceptable risk level.
Seek a multi-disciplined consensus on hazardcontrol
Results are used for:
Follow-up
Emergency Planning and
Training
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Concept
Process hazards analysis (PHAs) are usedto:
Identify
Evaluate and
Develop methods
to control significant hazards associatedwith HHP and LHO.
These hazards generally represent thepotential for:
Fires
Explosions
Release of toxic materials
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What is Risk?
Possibility of loss
or injury
Probabilityan
event may
impact
&
Consequence
of an eventwhen it impacts
Risk = or
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Consequence
Risk Lowering thru Multiple Protection
Layers
Hazard
Consequence
Frequency
High
Med
Low
V Lo
Inherently Safer
Design
Inspections &
Tests
Procedures and
Training
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Consequence
Risk Lowering thru Inherently Safer Design
Hazard
Consequence
Frequency
HighMedLow
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Consequence Probability Matrix
4
3
2
1
0
Freque
ncy
Low
High
0 1 2 3 4Consequence
Medium
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PHA Planning and Frequencies
ECPL has a process which includes: Annual PHA planning.
Conduct PHA (including consequence analysis),
Documentation and Follow up.
PHAs are mandatory and must be
conducted for:
New Project Facilities
Existing Facilities (cyclical PHAs),
Mothballing or Dismantling of Process Facilities or
Any Significant change requiring a Management of
Change Authorization e.g., Sub SOC etc.
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Team
Conducted by Trained Team Leaders & aCross Functional Team
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Consequence Analysis
Consequence Analysis - Based on scientific andempirical information.
Estimate a range of potential release quantities
including worst case.
Estimate down wind effects, concentration for toxic,
heat effects for ignition and overpressure for
explosives.
Estimate impact on on-site and off-site people andtheir environment.
Documentation of Consequence Analysis includes
reasons for Worst Case Scenario Selection,
Methods used and Assumptions made.
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Process Hazard Reviews
Process Hazard Review (PHR) shall beconducted using one of following 04
methodologies.
What If / Checklist
Hazard and Operability Study (HAZOP)
Fault Tree Analysis (FTA)
Failure Mode and Effect Analysis (FMEA)
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PHR method logic diagram
Cause
Deviation
Cosequence
What / If checklist
FMEA HAZOP
Fault Tree Analysis
Legends
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What / If Checklist
Strengths
Covers a broad range of hazards
Requires little prior training
Is effective as a learning tool
Challenge design
Recognizes effects of adjacent processes
Compares process with previous experience.
Limitations Short cut leads to weak reiew
Depth of analysis depends upon team diligence
Works only if right questions are asked.
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What /If checklist method
Select the process segment to be studied. List the worst case consequence and other hazardous events.
Generate a list of "what if" questions
Do not discuss answers
There are no dumb questions. Cover all parts of process segment.
Use checklist to prompt additional questions.
Review human factor and inherently safer processeschecklists.
Assign questions to individuals to develop responses.
Develop responses to all questions
Ensure that team reaches a consensus on all questions
Summarize the recommendations, highlighting the high priority
items.
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HAZOP
Strengths Methodical assessment of all deviations from
design intention
Good for novel situations
Easy to document
Designed for chemical processes but can beused elsewhere.
Limitations Assumes design is correct
Requires accurate model or diagram
Easy to get side tracked
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HAZOP Deviation matrix
MoreOf LessOf NoneOf Reverse Part Of As wellAS OtherThan
Flowhigh flow low flow no flow back flow wrong
concent
contaminants wrong
material
Temprature
high
temp
Low
temp
Pressurehigh
pressure
low
pressure
TimeToo long
too late
too short
too soon
misses a
step
steps
backward
action
missed
wrong time
Guided
words
Parameters
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HAZOP Method
Define design intent of NODE
List important parameters and develop
deviations using guide words.
List the consequence of deviation on entiresystem
List existing protection against deviations,
causes and consequences.
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FMEA
Strengths
Methodical approach to failure mode and
consequence
Breaks unusual processes into segments forcritical analysis.
Easy to use and document with proper training
Limitations
Focus on "go-no-go" situations
Does not question design basis
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FMEA Method
Recommended for analysis of smallsegments
Select process segment to be studied
List the worst case consequence Identify component and human failure
Describe the system in drawing
Describe each component and number it. List the failure mode and error mode of each
component.
For each failure list the potential worst case
consequence on whole system
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FMEA Method
Develop approximate ranking of events Evaluate adequacy of existing process safe guards
Identifies hazards that may require Fault tree analysis
Document review findings
Assign a "Hazard rating" to each failure Assign a "Probability of failure rating" to each failure.
Calculate "criticality" for each failure
List the curent protection against failure
Determine whether additional protection is needed for highcriticality items
Review human factor
Make recommendations where needed
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Fault Tree Analysis
Strengths
Defines various routes to top event
Quantifies probability of reaching top event
Analyze combination of events
Analyzes human error
Allows for comparison of the loss rates (dollars per year)
Limitations
Not readily understandable to readers Focus is on event vs. process
Requires specialist expertise
Considerable efforts and expense may be required
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FTA Method
The Undesired event is placed at the top ofthe tree
The possible causes of top event are
portrayed in the form of tree in reverse order Each sub-event should be evaluated
independently
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Evaluations and Risk Scoring
The team evaluates: The possible harmful effects of each event versus
The current protection and
Decides on whether additional protection is needed.
For each hazardous event identified, the PHA teamshall document:
Consequence (C1 C4)
Frequency rating (F1 F4) and
A risk level (1 IV)
In a PHR following shall also be looked into:
Inherently Safer Process
Human factors if the process in a HHP
Facility Siting"
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What If / Checklist Example
ProcessStep or
Equipment
Piece
What If .... ? Consequence ProtectionNow
Recommendation
P-2509s at
D-2528
Seal Leaks Ammonia will
release intoatmosphere
Routine
surveillanceby
operations.
Get the seal
replaced withdouble
mechanical
seal design
P-200A/B/C
pumpsStartup /
Shutdown
Operator
operateswrong valve
Pump can
rotate inreverse
direction.
Seals damage
and ammonia
release.
Recycle
valve onstandby
pumps kept
open. NH3
cannot go
back thru
pump
None
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Qualitative Risk Assessment Protocol
One or more fatalities or
irreversible health
effects.
Multiple MTC injuries;
1-2 RWC / LWCs or
moderate health effects.
Minor injury or
reversible health
effects
No injury or
health effects
Employee safety and
health
Death or irreversible
health effects. Liabilityfor injury + damages
more than $ 1 MM.
Injury or moderate
health effects. Liabilityfor injury + damages
$500 M - $ 1 MM
Minor injury of
reversible healtheffects
No injury or
health effects
Public s afety and health
C-4C-3C-2C-1Type of Event / impact
> 10 -2May occur at least once in the life time of the
installation
F-4 Likely
10-2 to 10 -3Unlikely to occur in the plants lifetime, but
could occur in one of number of similar
plants
F-3 Unlikely
10-3 to 10 -4Not expected to occur, but not incredibleF-2 Very unlikely
< 10 -4Not realistically expected to occurF-1 Extremely
unlikely (or remote)
Approximate corresponding
quantitative frequency (per
year)
Typical DescriptionCategory
Consequence Category
Increasing severity
C-4C-3C-2C-1
IIIIVIVIVF-1Increasing likelihood
IIIIIIVIVF-2
IIIIIIIVF-3
IIIIIVF-4Frequency category
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PHA Recommendations Approval and
Tracking
Recommendations are made based on Risk Scorefor each and every identified risk.
PHA recommendations shall be reviewed andapproved by Sub SOC
Case of Substantial Cost and / or Risk of non-compliance is very high are also reviewed in SubSOC(P/M) & SOC.
PHA report completion and circulation
responsibilities lie with the sponsor (OperationsUnit Managers / Relevant Section Head)
Follow up on recommendations is done by UnitManager.
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Record, Training and Follow-up
PHA Follow up Coordinator is SafetyAdvisor.
PHA follow up lists are issued monthly bySite Safety Advisor.
Completed PHA Recommendations arefiled for the life of facility.
Training of employees on the PHA methods
would be conducted periodically - recordkept.
The Emergency Response Coordinator isresponsible for follow up of risk analysisreviews related to Emergency
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PHA Activity Flow
When to conduct a PHA
Planning and Preparing to Conduct a PHA
Define PHA Charter and Scope
Team Preparation
Start PHA Activities
Process Hazard Review
Human Factors, Facility Siting and Inherently Safer Processes
Develop PHA Recommendations
PHA Report and Presentation to Management
Hazards Identification
Recommendations Follow-up, Tracking, Monthly Stewardship
Closing Recommendations
Team Responsibilities
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A Typical PHA Out Come
0
1
2
3
4
0 1 2 3 4
Sample Data
Frequency
Consequence
High Risk (5) Medium Risk (57)
Low Risk (349) Not Specified (0)
4 1
3
7 1
9 18 6
4 2 7
324
13 6
6
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Tips for PHA Team
When the team considers risk andconcludes that a recommendation is
appropriate, the recommendation should
be specific and accomplishable.
Do Not make make recommendations to
study, consider or investigate a
situation.
The team should do any investigation
needed, except in cases where a long range
investigation by an expert is needed.
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Questions.