PHA Training Presentation

7/28/2019 PHA Training Presentation

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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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Oct. 2004 3

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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Oct. 2004 27

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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