WELCOME

OSHO BABA

AN INTEGRATED STUDY ON

HAZOP

SAFETY ASSESSMENTSSafety samplingSafety surveyRisk assessmentSafety inspection Job safety analysis

THE MAJOR FORMALIZED TECHNIQUES ARE:

Hazards and Operability (HAZOP)

Fault Tree Analysis (FTA)

Failure mode-and-effect analysis (FMEA)

Safety audit

DEFINITION OF

“HAZOP”“A systematic study, carried out by a

team of persons experienced in aspects of the topic , using the line by line (or step by step) application of guidewords to identify all deviations from the design intent with undesirable effects for safety, operability or the environment.”Some “truths” emerge which are not always appreciated.

PHILOSOPHY OF HAZOP HAZOPs concentrate on

identifying both hazards as well as operability problems. Although hazard identification is the main focus, operability problems should be identified to the extent that they have the potential to lead to process hazards, result in an environmental violation or have a negative impact on profitability.

PHILOSOPHY OF HAZOP Hazard - any operation that could

possibly cause a catastrophic release of toxic, flammable or explosive chemicals or any action that could result in injury to personnel.

Operability - any operation inside the design envelope that would cause a shutdown that could possibly lead to a violation of environmental, health or safety regulations or negatively impact profitability.

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HAZOP study are applied during :

• Normal operation

• Foreseeable changes in operation, e.g. upgrading, reduced output, plant start-up and shut-down

• Suitability of plant materials, equipment and instrumentation

• failure of plant services, e. g . steam, electricity, cooling

water

• maintenance.

HAZOP Study

HAZOP TEAM FOR NEW DESIGN Design or Project Engineer

Process Engineer

Commissioning Manager

Instrument Design Engineer

HAZOP TEAM FOR EXISTING PLANT

Plant Superintendent

Process Engineer

Maintenance Engineer

Instrument Engineer

Technical Engineer

HAZOP KEY WORDSNo or NoneMoreLessAs well asPart ofOther thanReverse

HAZOP KEY WORDSGuide Word Deviation Example Interpretation

NO or NONE No part of the intention is achieved No forward flow when there should be.

MORE Quantitative increase in a physical property (rate or total quantity)

Higher pressure, flow rate, temperature...

Quantity of material is too large.

LESS Quantitative decrease in a physical property (rate or total quantity)

Lower pressure, flow rate, temperature...

Quantity of material is too small.

MORE THAN

or AS WELL AS

All intentions achieved, but with additional effects (qualitative increase)

Impurities in flow (air, water, oil...)

Chemicals present in more than one phase (vapour, solid)

PART OF Only some of the intention is achieved (qualitative decrease)

One or more components of mixture missing, or ratio of components is incorrect

OTHER THAN A result other than the intention is achieved

Unusual circumstances etc... see next slide

REVERSE The exact opposite of the intention is achieved

Reverse flow.

P & I DIAGRAM• A Piping and Instrumentation Diagram

- P&ID, is a schematic illustration of functional relationship of piping, instrumentation and system equipment components.

• P&ID represents the last step in process design.

• P&ID shows all of piping including the physical sequence of branches, valves, equipment, instrumentation and control interlocks. 

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GUIDELINES FOR DIVISION INTO SECTIONS

Choices of lines – P&ID must be divided logically. Not too many sections. Factors to be considered :

Each section should contain active components, which gives rise to deviations.

Ex: piping which contains control valves can give rise to flow deviations, heat exchangers can cause deviations.

Materials in section – contain significant amount of hazardous materials.

Section based on process and states of materials. Only 1 process operation per 1 section.

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• HAZOP is a systematic, reasonably comprehensive and flexible.

• It is suitable mainly for team use whereby it is possible to incorporate the general experience available.

• It gives good identification of cause and excellent identification of critical deviations.

• The use of keywords is effective and the whole group is able to participate.

• HAZOP is an excellent well-proven method for studying large plant in a specific manner.

• HAZOP identifies virtually all significant deviations on the plant, all major accidents should be identified but not necessarily their causes.

Strength of HAZOP

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HAZOP STUDY REPORT FORMTITLE :

Sheet 1 ofLINE 1 :

DEVIATION CAUSES CONSEQUENCES EXISTING PROVISIONS

ACTIONS, QUESTIONS OR

RECOMMENDATIONS

HAZOP Study Form

HAZOP PROCEDURE

Select a component

Select a flow

Suggest a deviation using a guide word

Investigate and document effects

Investigate and document causes

Record as non-hazardous deviation, with a

justification

Record as hazard. Make recommendations for

action if necessary

Start Finish

All components analysed?

All flows analysed?

All guide words considered?

Does deviation have plausiblecauses and hazardous effects?

YES

YES

YES

NO

NO

NO

NO YES

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CASE STUDY – SHELL & TUBE HEAT EXCHANGER Using relevant guide works, perform HAZOP study on shell

& tube heat exchanger

Processfluid

Cooling water

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HAZOP ON HEAT EXCHANGER – ANSWER 1

Guide Word Deviation Causes Consequences Action

Less Less flow of cooling water

Pipe blockage Temperature of process fluid remains constant

High Temperature Alarm

More More cooling flow

Failure of cooling water valve

Temperature of process fluid decrease

Low Temperature Alarm

More of More pressure on tube side

Failure of process fluid valve

Bursting of tube Install high pressure alarm

Contamination Contamination of process fluid line

Leakage of tube and cooling water goes in

Contamination of process fluid

Proper maintainance and operator alert

Corrosion Corrosion of tube

Hardness of cooling water

Less cooling and crack of tube

Proper maintainence

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HAZOP ON HEAT EXCHANGER

Guide Word Deviation Causes Consequences Action

NONE No cooling water flow Failure of inlet cooling water valve to open

Process fluid temperature is not lowered accordingly

Install Temperature indicator before and after the process fluid line

MORE More cooling water flow

Failure of inlet cooling water valve to close

Output of Process fluid temperature too low

Install Temperature indicator before and after process fluid lineInstall TAL

LESS Less cooling water Pipe leakage Process fluid temperature too low

Installation of flow meter

REVERSE Reverse process fluid flow

Failure of process fluid inlet valve

Product off set Install check valve (whether it is crucial have to check?)

CONTAMINATION Process fluid contamination

Contamination in cooling water

Outlet temperature too low Proper maintenance and operator alert

THANK YOU VERY MUCH