7/21/2019 212625045-HAZOP

1/28

HAZOP STUDY

Sabic E&PM Process & Process Safety SectionMarch 2007

7/21/2019 212625045-HAZOP

2/28

HAZOP STUDY

1.0 INTRODUCTION

HAZOP stands for HAZARD AND OPERABILITY

The application of a formal, systematic, critical, rigorous

examination to the process and engineering intentions

of new & existing facilities to assess the hazard

potential of mal -operation or mal -function of

individual items of equipment & the consequential

effects on the facility as a whole.

7/21/2019 212625045-HAZOP

3/28

HAZOP STUDY

1.1 Hazards & Risks.

Hazard is a physical situation with the potential for

human injury, damage to property, damage to the

environment or a combination of these.

Risk is the likelihood of an undesirable event occurring

within a specific period or under specified circumstance.

7/21/2019 212625045-HAZOP

4/28

HAZOP STUDY

1.2 Hazard Studies & SABIC Project Gate Process

: Hazard Reviews/Studies part of Safety Management

System (SMS),

: To identify safety, health, environment, operating and

maintenance problems.

: New Projects, a number of studies in different stages.

: Each study also verifies recommendations of previous

study have been implemented.

7/21/2019 212625045-HAZOP

5/28

HAZOP STUDY

1.3 SABIC PROJECT GATE PROCESS1.0 Concept Rationalization & Pre-feasibility.

2.0 Feasibility Study and Venture Philosophy (Preliminary HSE Review-

PHA I)

3.0 Project Strategy & Execution Plan.

4.0 Design Basis Development (PHA II)

5.0 Basic Design and Appropriation (HAZOP-PHA III)

6.0 Detailed Design and Construction .7.0 Close Out and Reappraisal Phase (PSSR)

SABIC Project Gate Process: At Gate 5, Basic Design and appropriation,

a detailed HAZOP study is carried out.

The application of HAZOP at the correct stage in a project means that

problems are identified and can be rectified during detailed design.This results in substantial savings.

7/21/2019 212625045-HAZOP

6/28

HAZOP STUDY

1.4 Objectives of the Study: Identifies process hazards that could lead to safety

related consequences

: Identifies operability or product quality problems

: Identifies quality issues in design

: Identifies maintenance issues.: Recommend actions to minimise risks associated

with identified hazards or eliminate the Hazard

HAZOP is an identifying technique & is not intended as a

means of solving problems.

7/21/2019 212625045-HAZOP

7/28

HAZOP STUDY

1.5 Benefits of a Hazop Study

: Increased plant availability hence production

: Improved product quality

: Improved quality of working environment

: Reduced insurance premiums

: Minimises & controls changes to design

7/21/2019 212625045-HAZOP

8/28

HAZOP STUDY

1.6 Limitations of a Hazop Study

Hazop Study is not an infallible method for

identifying all possible hazards.

Quality of the Study depends on -

:Expertise and experience of the team

:Accuracy and extent of information available

:Clear definition of scope of study

:Duration of the study:Good knowledge of the system

:Creativity of the team members

7/21/2019 212625045-HAZOP

9/28

HAZOP STUDY

1.7 Scheduling a Hazop Study

Prerequisites :

- Design must be well developed and firm.

- Drawings must be well prepared.

- Sufficient vendor information must be

available.

- Study must not be delayed too long.

7/21/2019 212625045-HAZOP

10/28

HAZOP STUDY

1.8 Applicable Systems

New designs.

Modification of existing Operations.

Repeat designs.

Existing Plants.Computer controlled processes.

Operating Procedures.

Pilot Plant and Laboratory processes.

Drains, vents and tie-in between Plants.

Commissioning and Decommissioning.

Emergency Operations.

7/21/2019 212625045-HAZOP

11/28

HAZOP STUDY

1.9 Basic Concept of HAZOP

Involves the splitting up of the plant (P & ID) into sections &the systematic application of a series of questions to each

section. The following terms are used as a basis for all

HAZOP studies:

Design intent - The way in which the plant is intended to operate.

Deviation - Any perceived deviations in operation from thedesign intent.

Cause - The causes of the perceived deviations

Safeguards - Existing provisions to mitigate the likelihood or

consequences of the perceived deviations &

to inform operators of their occurrenceActions -The recommendations or requests for information

made by the study team in order to improve the

safety and/or operability of the plant

7/21/2019 212625045-HAZOP

12/28

HAZOP STUDY

1.10 GuideWords& SystemParameters

Guide wordis an action word or phrase that assists the

team in a creative and thorough search for

meaningful deviations

:no, less, more, reverse etc.

System parameter is a variable, component or

activity associated with the stage under study

:flow, pressure, reaction, maintenance etc.

Not all Parameters apply to the study.

7/21/2019 212625045-HAZOP

13/28

HAZOP STUDY

HAZOP MATRIX

No Less More As well as Part of Reverse Other

thanFlow No flow Low flow High flow Misdirected Reverse

flow flow

Pressure Open to. Low pr. High pr. Vacuumatm.

Reaction No reaction Low react- High react- Side Incomplete Reverse Wrongion Rate ion rate reaction reaction reaction reaction

Vibration Low Highvibration vibration

Startup Incomplete Improperstart up start up

Mainte- Inability to Inadequate Additional Impropernance Maintain maintenance effort to mainte-

maintain nance

7/21/2019 212625045-HAZOP

14/28

HAZOP STUDY

1.11 Quantification

Whilst the HAZOP techniques was originally

conceived as a purely qualitative review, it can

be quantified to some extent by the use of

a simple ranking for likelihood & severity.

A typical likelihood ranking is as follows:1 Very Unlikely

2 Unlikely

3 Has happened once

4 Has happened a few times

5 Happens quite often

7/21/2019 212625045-HAZOP

15/28

HAZOP STUDY

A typical severity ranking is as follows :

1 Pollution

2 Minor injury/damage

3 Serious injury/damage

4 Fatalities/Major Damage5 Loss of installation

The two factors (Likelihood & Severity) can be

combined in a matrix to give an overall ranking

which can be used to prioritize actions.

7/21/2019 212625045-HAZOP

16/28

HAZOP STUDY

2.0 ORGANISING A HAZOP STUDY2.1 Scope of Study

. HSE issues?

. Operation, product quality & productivity issues?

. Maintenance, reliability, and Plant life ?

. Adherence to Company Policies & Procedures?

. Quality issues in Process design?

. Extended to Equipments and Machinery?

. Boundaries for the study?

. Problems beyond the boundaries be addressed?

. Hazop repeat designs or Hazopby difference?. Should non- steady state operations be included?

. Approach to Action Items or recommendations.

. How will redesign issues be handled?

7/21/2019 212625045-HAZOP

17/28

HAZOP STUDY

2.2 The Team- Study is only as good as the Team undertaking the study

- Composition dependent on Nature and complexity

- Expertise in basic disciplines and system operations

A typical team comprises:Chairman or Team leader,

Secretary/scribe,

Project Engineer,

Process Engineer,

Control and Instrument Engineer,Safety Engineer,

Operations Specialist (Lead Commissioning Engineer).

Other specialists may be consulted for specific points.

7/21/2019 212625045-HAZOP

18/28

HAZOP STUDY

2.3 Documents RequiredOperating and Control Philosophy doc. PFD, UFD, P&IDs

Material and Energy Balance Equipment specs

Vendor packages, Instrument specs

Relief / Venting philosophy Alarm and Trip settings

Material Safety Data Sheets Material reactivity dataDocs. of Hazards in similar systems Operating problems

Plot Plan Previous Safety Reports

Operation method (Batch Process)

7/21/2019 212625045-HAZOP

19/28

HAZOP STUDY

2.4 Recording the Proceedings

7/21/2019 212625045-HAZOP

20/28

HAZOP STUDY

3.0 HAZOP Study Procedure

7/21/2019 212625045-HAZOP

21/28

HAZOP STUDY

3.1 NodeSection of the Plant under Study; marked and no. on a P&ID.

Guidelines for creating Nodes

: Each Node should fit a clear Design Intention.

: Create a definitive conceptual model of the system.

: Control points or junctions of vessels.: Variation in Parameters as flow, pr., temp. & composition.

: In Batch Process, the sequential steps of operation.

Too many small Nodes

: Time consuming and expensive exercise.

: Analysis spills over to upstream and downstream sections.Too large a Node

: More than one Design Intention for the Node

7/21/2019 212625045-HAZOP

22/28

HAZOP STUDY

3.2 Node and its Design Intent

Description to include Operational range and Design Intent,

reference to equipments, to materials, conditions, source and

destination, to changes or transfers, to means of control and

timing of a step

3.3 Generate a Deviation

: Assign a Parameter, vary Guide Words.

: All combinations may not apply.Ex. - Higher Pressure.

7/21/2019 212625045-HAZOP

23/28

HAZOP STUDY

3.4 Identify the Causes

: All Causes to be identified before proceeding to next

step.

: Only realistic causes to be investigated. Quantitative Risk

Assessment (QRA) based on a combination of frequency ofevent and seriousness of the consequences.

: Include low frequency causeswith severe Consequences.

3.5 Evaluate Consequences

: Both immediate and delayed

: Both inside and outside the Node

7/21/2019 212625045-HAZOP

24/28

HAZOP STUDY

3.6 Categories for Consequences

S : Personnel Safety Impacted.ED : Equipment Damage.

BI : Business Interruption.

PRO: Loss of or Reduced Production.

E/H : Environment or Health Related.

Q : Product Quality Impact

3.7 Safeguards

Equipment or process feature(s) or procedural step(s), reducing the

likelihood of one or more Cause or severity of the

Consequence.

-Identify the worst Consequence and list Safeguard for this.-Be physically located within or directly applicable to the Node.

7/21/2019 212625045-HAZOP

25/28

HAZOP STUDY

3.8 Action Items: Adding hardware, providing interlocks, modifying

procedures or evaluating design adequacy.

: Only unanimously agreed solution(s)

: To be treated purely as recommendations of the Team.

: More effective protection could be available.: Suggested Action may not be feasible.

: Actions should be documented without ambiguity.

: For no action, write NoAction Required

7/21/2019 212625045-HAZOP

26/28

HAZOP STUDY

3.9 Remarks

Record any Remarks that will amplify the Deviation.

Ex : During normal operation, PIC-1 will limit flow

below set point of FIC-1.

: Valve CV changed from 300 to 400 to cope with

anticipated flow rate increase from 50K to 83K kg/h.3.10 Assign Responsibility in BYcolumn: Ex. - Client.

3.11 Record Status of Action Item in XcolumnBlank :Action item remains open for designated BYparty

C : Action completed with Comments

X : Action not required for Comments given.

R : Further Action required by a different BY team.

I : Action incomplete.

7/21/2019 212625045-HAZOP

27/28

HAZOP STUDY

CONCLUSION

The success or failure of a HAZOP study depends upon:

The accuracy of drawings & other documents used in the

study.

The expertise & experience of the team.

The ability of the team to visualize deviations, causes &consequences.

The ability of the team to assess the seriousness of

hazards.

The skill of the chairman in keeping the study on track.

7/21/2019 212625045-HAZOP

28/28

THANKS