ENERGYEDGE WELCOMES YOU TO

Process Hazard Assessment Using The

HAZOP Technique And HAZOP Team Leader
Training
Instructor:
Alan Borrowman

11 – 15 September 2023 2PM – 6PM (Malaysia Time)

HAZOP Technique
Module 2.1 : Types of HAZOP
 In this module

 6 Stages of Hazard Studies

 HAZOP of Batch Processes
 HAZOP of Operating Procedure
 Group Exercise of Procedure HAZOP

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 When HAZOP Studies are undertaken

A HAZOP study is required for:

◆ design process for a new project

◆ design process for a plant modification
◆ re-HAZOP of existing facilities
◆ plant modifications (projects)
◆ safety critical procedures
◆ non-routine operations
◆ process change e.g. feedstock / catalyst / products
◆ support the Management of Change procedure

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 Timing of HAZOP Studies

Hazard identification studies can be performed at

several points in the lifetime of a facility:
Concept Development
Front End Engineering Design (FEED)
Detailed Design
Commissioning / Pre-Start Up
Post-Start Up (after 3-6 months)
Re-validation (re-do HAZOP every 5 years)
Decommissioning/Demolition/Abandonment
 6 Stages of Hazard Identification Studies
(refer to IEC 61882: 2016)
1. Concept stage : The design concept and major system parts are decided but the
detailed design documentation for HAZOP study do not exist.
2. Early Design stage : The main elements of the design and outline operating method
are decided. Changes can be made without major cost. It allows long delivery items
to be ordered and provides a basis for cost estimate for project approval.
3. Detailed Design stage : The process design is ‘frozen’ when 80 – 90% complete,
allowing time to make changes from the ‘main’ HAZOP before installation starts.
4. Pre-Start Up stage : Carried out before hazardous materials are introduced. Status
of actions from previous HAZOP studies and construction snag lists are reviewed
with comprehensive site checks that functional testing is complete.
5. Periodic Re-Validation : Considers the effect of any changes in design or operation a
few months after commissioning and then typically every 5 years.
6. De-Commissioning stage : Review activities related to decommissioning, cessation
of use or disposal if there are different risks from those in normal operations.
 Six Stages of Process Hazard Studies
Hazardous materials
VAR 1 VAR 2 VAR 3introduced
HAZID
Coarse Procedure
HAZOP HAZOP After 3 - 6
Main months then
HAZOP every 5 years
De-Comm
Pre-start
HAZOP
Up Review
Validation
HAZOP

1. Assess 2. Select 3. Define 5. Pre-Comm 6. Post 6. De-Comm

(Concept) (FEED) (Detail Start Up
Design)
Will it work?
Ability to change the design Did it work?
 Validation using ‘Delta HAZOP’
Review of ‘creeping’ changes since the last HAZOP to identify hazards
resulting from those changes, looking for trends. The focus is on :
▪ changes to equipment, instrumentation (such as alarm activations) and
plant operational data.
▪ missing MOCs and temporary MOCs still open
▪ ‘near miss’ incidents
▪ failure rates of safety-critical devices

Requirements
• At least two prior HAZOPs with the previous one verified as high quality.
• All findings of the previous two HAZOPs have been resolved and most
medium or higher-risk items have been implemented.
• All modifications since the last HAZOP have been controlled by MOC.
• Must have an effective and documented MOC system.
❖ Only applicable to a mature operating facility
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 Cost of Change

Cost

FEED Detail Design Execution

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 Batch Processes

Characterised by

• More common in food and pharma industries

• Multiple use of same equipment
• Sequential steps, some repetition
• Predominance of manual inputs, opportunity for error
• Usually small volumes but can be high hazard
• Contamination from residuals if not cleaned

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 Batch HAZOP
• Subdivide process steps into nodes
• Equipment may have multiple uses, so several ‘operating
modes’
• Guidewords = add, mix, heat, cool, transfer, etc
• Include appropriate human intervention deviations:
Time – more, less, none, wrong
Action – more, less, none, wrong
Sequence – sooner, later, not at all
• Same planning and preparation as for continuous HAZOP
• Useful to prepare a timeline of the batch process
• May take longer than a continuous process HAZOP for the
same number of P&ID’s.
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Batch HAZOP study
 Procedural HAZOP study

• Similar guidewords to batch HAZOP

• Written procedure is subdivided into steps
• Steps become the nodes
• Operator involvement likely to be high
• Other operability parameters:
HSE – toxicity, flammability, exposure, noise, PPE
Ergonomics – manual handling, work area layout, feedback
mechanisms, manual input panels & displays
• On site checks for practicality, feasibility
• Specific practical experience in team
• Make recommendations for improvements, don’t rewrite

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 Pre-Start Up Review
Conducted prior to introducing hazardous substances.
PSUR procedure is normally prepared as part of pre-commissioning/
commissioning documentation.
It covers not only equipment, but also procedures and training, to ensure:

❖ Installation meets the original design and operating intent of process

plant/facility.
❖ Safety, operating, maintenance and emergency procedures are adequate.
❖ Actions from safety reviews during engineering phase (HAZOP study,
model review etc.) have been completed.
❖ Any post-HAZOP design changes or site modifications during construction
phase have been properly controlled and documented.
❖ Training of each employee involved in the operating process is completed.
 Pre-Start Up Review

Carried out on site when mechanical completion is about 90-95

% complete and the site is reasonably accessible, concentrating
on such issues as:
❖ Equipment operability and maintainability
❖ Outstanding punch list items from mechanical completion
❖ Outstanding actions from previous HAZOP / HAZID studies
❖ Access / exit routes for operators and maintainers
❖ Security of small-bore connections
❖ Location of emergency and safety equipment, warning signs
❖ Fire and gas detectors
❖ Locking systems
 Post-Start Up Review

Many minor changes and adjustments may be made during

commissioning and early production in order to stabilise and
optimise plant operation. The changes may not be formally
recorded at the time.
The details need to be gathered, drawings updated to ‘as-built
status’ and operating procedures finalised.
A post-start up review would typically occur 3 to 6 months after
the first introduction of hazardous materials.
It is an opportunity to check that the changes do not invalidate
previous HAZOP findings.
 Exercise 5 - Procedural HAZOP

Process Description

• A large water tank is supplied with cold water via valve (7)
• Temperature controller (3) controls gas flow to the burner (10) via
valve (2)
• Continuous pilot light (5) reignites burner when gas valve is
opened by temperature controller
• Overpressure protection is provided by relief valve (1)

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Procedural HAZOP - Hot water boiler

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 Procedural Hazop - Deviations and Operability parameters

Flow – no, more, less, reverse

Temperature – more, less

Pressure – more, less

Level – more, less (incl. No)

Time – more, less, none, wrong

Action – more, less, none, wrong

Sequence – sooner, later, not at all

Operability – flammability, ergonomics

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 Procedural HAZOP
Hot water system boiler light up procedure
1. Ensure manual gas shut off valve (8) is closed
2. Ensure temperature controller (3) set point is set to minimum
3. Ensure water drain valve (12) is closed
4. Ensure hot water valve (11) is open and vent system through a nearby hot
water tap.
5. Open cold water supply valve (7) and allow tank to fill for 15 minutes. Close
the hot water tap
6. Observe the pressure gauge (6) for water supply pressure
7. Open the manual shut off valve (8)
8. Open the pilot valve (9) and ignite the pilot (5) manually
9. Raise the set point of the temperature controller to the desired temperature.
10. Observe the main burner to ensure ignition has taken place

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 Procedural HAZOP - Hot water system – suggested nodes.

NODE 1- all are checks prior to actions

1. Ensure manual gas shut off valve (8) is closed

2. Ensure temperature controller (3) set point is set to
minimum
3. Ensure water drain valve (12) is closed
4. Ensure hot water valve (11) is open and vent system through
a nearby hot water tap.

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 Suggested Nodes

NODE 2

5. Open cold water supply valve (7) and allow tank to fill for 15 minutes. Close the
hot water tap
6. Observe the pressure gauge (6) for water supply pressure

NODE 3

7. Open the manual shut off valve (8)

8. Open the pilot valve (9) and ignite the pilot (5) manually

NODE 4

9. Raise the set point of the temperature controller to the desired temperature.
10. Observe the main burner to ensure ignition has taken place

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End of module

Any questions ?

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HAZOP Technique
Module 2.2 : HAZOP Roles
 In this Module
The main roles and responsibilities of the core
members of the HAZOP team :-
❖ Team Leader or Facilitator
❖ Secretary or Scribe/Recorder
❖ Independent Process Engineer
❖ Operations Representative
❖ Process Design Engineer
❖ Instrument & Control Engineer

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 The HAZOP Team

1. HAZOP Team Leader

Role : to ensure the HAZOP technique is applied correctly

Must be : expert in use of HAZOP

independent technical
experienced constructive
meticulous arbitrator

Must not : be domineering

have own agenda
lose control of meeting

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 HAZOP Team cont’d
2. HAZOP Secretary/Scribe
Role : accurately complete HAZOP worksheets
Should be : familiar with technology / terminology
of at least average typing ability
familiar with word processing package
able to record with minimal direction

3. Independent Process Engineer

Role: question design assumptions
Should be : chartered chemical/process engineer
min. 5 years experience
independent of design
familiar with the process technology

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 HAZOP Team cont’d
4. Operations Representative

Role : identify operability problems

Should be : experienced in operation of the type of plant
knowledgable of safe operational practice
able to understand process drawings
5. Process Design Engineer

Role : explain design intent

Should be : familar with basis of process/control design
knowledgable of design codes & standards
able to call upon other disciplines as required

6. Instrument / Control Engineer

Role : explain detailed design of process control, alarms,
shutdown system, fire & gas detection system
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 Supporting Roles

Other personnel may be required to provide information on a full-time or

part-time basis, as appropriate

Other Discipline Design Engineers

Role : explain design of mechanical, electrical, HVAC, telecomms, etc

(Technical) HSE Engineer

Role : explain company HSE standards and design practices, advise on
risk analysis and assessment.
Plant Engineer
Role : explain maintenance requirements

Vendor Representative
Role : explain design/operation of his equipment

Specialists e.g. metallurgist, chemist, human factors

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End of module

Any questions ?

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HAZOP Technique
Module 2.3 : HAZID
 In this Module

HAZID is seen as complementary to HAZOP. Although

the approach is similar, there are differences in the
scope, guidewords and information requirements.

We will identify these differences and work through a

HAZID worksheet to understand the HAZID process.
 HAZID

HAZOP is concerned with deviations arising from or within

process equipment, HAZID predominantly addresses hazards
outside the envelope of the process equipment, i.e.

◆ Fire & explosion and other process-related hazards

◆ Impact from and effect on the environment
◆ Facility operation and maintenance
◆ Health hazard exposure
◆ Project implementation issues
◆ Management system issues
 HAZOP & HAZID
HAZOP = HAZard and OPerability Study
Hazard : threats to personnel, plant, enviro from process deviations
Operability : poor ergonomics, unsafe practices, excessive workload
HAZOP is concerned with deviations from design intent occurring inside the
process plant envelope (equipment, pipework, instruments).
Focuses on Guideword - Deviation - Cause - Consequence - Safeguards
Study ‘Nodes’ are sections of pipework or equipment items.

HAZID = Hazard Identification Study

HAZID is concerned with all types of deviations occurring outside the process
plant envelope, such as bad weather, collision, unsafe working, pollution.
Study ‘Nodes’ can be equipment items, areas of plant, operating activities, etc.
Focuses on Hazard – Threats – Controls – Consequences –Recovery.
Scenarios are risk assessed for harm to people / enviro / project / reputation.
 When to Conduct a HAZID
• HAZID process should be ongoing to
ensure existing hazards are known,
and new hazards recognised before
they are introduced:
– Prior to modification of facility
– Prior to change in organisation
– Before and during abnormal
operations, troubleshooting
– Plant condition monitoring, early
warning signals
– Employee feedback from routine
participation in work
– After an incident
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 Information Requirements

HAZID requires a wider section of reference documentation

than HAZOP

Process flow diagrams Project execution plan

Heat & mass balance Standards & regulations
Process description Chemical data sheets
Plant layouts Feasibility studies
Philosophies : e.g. safety, design, operating, safeguarding
 HAZID Guidewords
Hydro-carbon Hazards Layout, overpressure, over/under temp.,
composition, loss of containment, ignition
source, flammable materials, gas detection
Equipment/Plant Failure Integrity, installation, dissimilarities
Utility Systems Adequacy or failure of
Operation & Control Different operating modes,
commissioning, start-up, normal &
emergency shutdown
Maintenance Preparation, execution, re-instatement,
related tasks
Natural Environment Weather
Transport Vessels, air, land
Health Hazards Exposure, chemicals, working conditions
Damage to Environment Discharges to air, sea; pollution control
HSE Management Command & control, communications,
emergency response, security, interfaces,
manning, training, supervision
Detailed HAZID Guidewords (1 of 2)
Detailed HAZID Guidewords (2 of 2)
 Methodology
1. Explain the design intent and operating mode of the node.
2. Select a Parameter, e.g. Natural Environment.
3. Select a Guideword.
4. Identify potential deviations from the design intent / operating mode
5. Determine if the deviation gives rise to a significant safety or
environmental hazard.
6. If so, record the hazard, its cause, its immediate effects and the
consequences for personnel and environment.
7. Identify and record the existing safeguards (prevention barriers
and consequence controls).
8. Assess the risk using a Risk Assessment Matrix.
9. Record the highest risk for safety, environment, or economic.
10. Depending on the risk ranking (High, Medium, Low), make and
record recommendations to reduce risk to an acceptable level.
 HAZID Worksheet (without risk ranking)
Project Title: Oil Refinery Date: Sheet No:
Node/Activity/Scope: Export tank farm from custody meters up to loading jetty Drawings:

Guideword Hazardous Event Consequence Safeguards Risk Evaluation Recommendation By

Rim fire on Prevention: Main cost is to Instruct Joe

Lightning strike on top of oil tank lightning re-instate tank, maintenance
Natural oil storage tank with possible protection to covered by supervisor that
environment escalation to codes. insurance, and 1 work on tank
major fire day downtime to tops should stop
Control:
causing loss assign standby for duration of
Step 2 Remotely
of tank tank. Few thunderstorm.
Use team’s operated foam
inventory and personnel at risk.
experience nozzles on tank
damage to Major spill but
Step 1 to identify roof.
adjacent contained and
Consider causes of
tanks Mitigation: fully recoverable.
deviations hazard Step 6
each tank
from expected Finally, recommend
individually
conditions actions, if necessary,
bunded.
to achieve required
Step 4 degree of risk control
Step 3
What hardware protection Step 5
Identify immediate effects and
or operational controls Summarise why risk is/is not
wider impacts on personnel
are currently in place to acceptable and why additional
safety, environment, company
prevent, control or mitigate safeguards are/are not required
reputation or business
the hazard
 Risk Ranking Matrix
Probability
A B C D E
Unlikely Highly Improbable Probable Frequent
Improbable

1 Negligible

2 Minor
Severity

3 Significant

4 Severe
Catastrophic
5

High Intolerable: Risk reduction is mandatory.

Tolerable if ALARP: ALARP shall be demonstrated and
documented.
Tolerable: Maintain systematic controls and aim to continuously
improve.
Low: Main systematic controls and monitor.
End of module

Any questions ?

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