Lect 3 - Fmea & rev

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Hazard IdentificationFMEA HAZ P

Prof. Ir. Dr. Mohd Sobri Takriff

Dept. of Chemical & Process Engineering,

FMEA

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What is FMEA?

FMEA is an acron m that stands forFailure Modes and Effects Analysis

Identifies the potential failure of a systemand its effects

that would eliminate the chance ofoccurrence

Documents the potential failures

1963 1965 1975 1977 1980 1986 1990 1996 1998

NASA Aeronautics Nuclear Presentation Standard- Use in Use in Further Increasedand space Engi- of the FMEA ization in the auto- the different development use in the

travel neering to the auto- Germany motive branches of to the system automotive

The History of the FMEA

motive industry industry FMEA industryindustry (first of all, (since 94(Ford) suppliers) at AOAG)

QS 9000

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FMEA

Oriented towards e ui ment rather thanprocess

Paticularly suited for mechanical and electricalsystems

FMEA systematically

on that system

determines the significance of each failure modewith regard to the system's performance

Applications & Benefits?

May be applied at various stages

Design

Process (operation)

Service and Maintenance

Improvements in: a e y

Quality

Reliability

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FMEA - Methodology

define the s stem to be evaluated

establish the level of analysis

Failure Analysis identify failure modes, causes and consequences

as well as design and operating provisions againstsuch failures

Reporting

FMEA System Definition

define the extent of the s stem to beanalyzed

usually performed in relatively small steps

Requires analysts / personnels with aknowledge of the system

system and their performance requirements

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FMEA Level of Analysis

based on the functional structure of a s stem

the failure modes are expressed as failure toperform a particular subsystem function

primary function is that for which the subsystemwas rovided

secondary function is one which is merely aconsequence of the subsystem's presence

FMEA Analysis of Failures

remature o eration

failure to operate when required

intermittent operationfailure to cease operation when required

loss of output or failure during operation

degraded output

etc

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FMEA Analysis of Failures

Based on Failure modes

looks at the likely causes and the effects on boththe components and the system

consideration is given to the relative importance ofthe effects and the sequence

safeguards against such failures and methods ofdetecting them are then examined

FMEA - Reporting

identif the most si nificant failures in termsof their effects on the overall system

decide whether or not the existing safeguardsand detection devices are adequate

more detailed analysis on the weak link

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FMEA - Reporting

No standard re ortin format t icall covers The unit/system

Failure mode

Consequence of failure

Symptoms

safeguards

Example 1Household Water Supply system

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FMEA Household water supply system

Water Supp y System FMEA

No Component

DescriptionFailure mode Failure effect(s) Symtoms

Safe

GuardsActions

1 Kitchen Tap Fails open Kitchen Flooded

Water

continuously

flowing out-

Install flow

control valve

2Inlet pipe

(2 in PVC)Blocked Water Tank Dry

No water at

kitchen tap -

Install waterfilter

Clean filter

periodically


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Failure Mode Effect Analysis(FMEA)

CRITICALITY ANALYSIS

Criticality is defined in the same way as risk - thatis, a combination of the severity of an effect andthe probability or expected frequency

simplest approach requires a form of ranking or

effect / consequence

frequency


of the following categories loss of mission due to inability of equipment to

perform

economic loss due to lack of output orfunction

damage to plant or third party property

injury to operating personnel or the public

death to operating personnel or the publicand/or significant damage to the environment

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order or severity)

catastrophic - may cause death or totalsystem loss

critical- may cause severe injury or

major - may cause some injury or damage

minor - requires unscheduled maintenance.


uantification of fre uenc de ends on thedata available and may again be a simpleranking, such as one depending on failure

probability during the operating time interval extremely unlikely

remote

ccas ona

reasonably frequent

frequent

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extremely unlikely - 0.001

remote - between 0.001 and 0.01

occasional- between 0.01 and 0.1

- .and 0.2

frequent - 0.2.


5 A C C D D

4 A B C C D3 A B B C C

2 A A B B C

1

1 2 3 4 5

A B C DACCEPTABLE UNACCEPTABLE

Threshold value = 10

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FMEA

-

reduce probability that the cause offailure will result in the failure mode

reduce severity of failure by redesignor add rotection redundanc

increase probability of detection

HAZOP

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HAZOP

OPerability studies

The term 'HAZOP' originated in ICI andfirst appeared in the literature in the

early 1970s

HAZOPSkelton, B, 1997

, , ,the process and engineering intentions of new andexisting facilities to assess the hazard potential of mal-

operation or mal-function of individual items of equipment and the consequential effects

e s, ,

HAZOP is formal, systematic examination of aprocessing plant in order to identify hazards, failuresand operability problems, and assess theconsequences from such mal-operation

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WHY DO HAZOP??

Generates a list of identified roblemsusually with some suggestions forimprovement of the system

improves safety, reliability and quality bymaking people more aware of potential

.

help to sort out loopholes and inconsistenciesin procedures and force plant personnel toget their instructions up to date

HAZOP

Basic hiloso h if a process operates within its intended

design philosophy then undesired

hazardous events should not occur

The ob ective of a HAZOP mainly to identify how process deviations

can be prevented or mitigated to minimizeprocess hazards

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Basic Ideas of HAZOP

to stimulate the ima ination of a reviewteam, including designers and operators, in asystematic way so that they can identifypotential hazards in a design

in order to consider all the possible ways thatprocess and operational failures can occur

HAZOP

recommend necessary changes to asystem to meet company risk guidelines

recommend procedures or changes fore m na ng or re uc ng e pro a y ooperating deviations.

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HAZOP

a lication at the correct sta e in aproject means that problems areidentified and can be rectified duringdetailed design.

material for inclusion in the plantoperating instructions

HAZOP Terminology

Desi n 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 perceiveddeviations.

Consequence

the consequences of the perceived deviations

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Hazop TerminologySafeguards

consequences of the perceived deviations and to informoperators of their occurrence

Actions the recommendations or requests for information made by

the study team in order to improve the safety and/or

operability of the plant.

u e wor s simple words used to qualify the intent and hence discover

deviations.

Parameters basic process requirements such as 'flow', 'temperature',

'pres-sure' and so on.

HAZOP COMPONENTS

Procedure

Guide words

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Hazop Team

normall com rises between four and ei htmembers, each of whom can provide knowledge and

experience appropriate to the project to bestudied

efficient and allow each member to make acontribution, whilst containing sufficient skillsand experience to cover the area of studycomprehensively

Hazop Team

Hazop team:

those with detailed technical knowledge ofthe process;

those with knowledge and experience of

chair and report upon technical meetings

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Hazop Team

t ical member of a Hazo team

chairman or team leader

secretary

process design engineer

control engineer

operations specialist

project engineer

Other specialists may be consulted or beavailable for specific points

Hazop Team

selected for his or her ability to effectivelylead the study

should have sufficient seniority to give thestudy recommendations the proper level of

knowledge and experience of the Hazoptechnique

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Hazop Team

should have a technical appreciation of theproject and be familiar with the HAZOPtechnique

technical members usually part of the project design team

Hazop PROCEDURE1. Begin with a detailed flow sheet. Break the flow

eg the reactor area might be one unit, and the storagetank another. Select a unit for study.

2. Choose a study node (vessel, line, operatinginstruction).

3. Describe the design intent of the study node. eg example, vessel V-I is designed to store the benzene

feedstock and provide it on demand to the reactor.

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Hazop PROCEDURE4. Pick a process parameter:

,

level,

temperature,

pressure,

concentration,

pH,

viscosit

power,

Inert

etc

Hazop PROCEDURE

5. Apply a guide word to the process parameter to.

NO

MORE

LESS REVERSE

etc

6. If the deviation is applicable, determine possiblecauses and note any protective systems.

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Hazop PROCEDURE7. Evaluate the consequences of the

.

8. Recommend action what?

by whom?

b when?

Hazop PROCEDURE

9. Record all information.

10.Repeat steps 5 through 9 until allapplicable guide words have beenapplied to the chosen process

.

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Hazop PROCEDURE

11. Re eat ste s 4 throu h 10 until all a licableprocess parameters have been considered forthe given study node.

12. Repeat steps 2 through 11 until all studynodes have been considered for the givensection and roceed to the next section on the

flow sheet.

Hazop PROCEDURE

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Hazop GUIDE WORDSGuide words Meaning Comments

NO, NOT,

NONE

The complete negation of the

intention Quantitative decrease

No part of the design intention is achieved, but

nothing else happens.

MORE, HIGHER,GREATER

LESS, LOWERQuantitative increase

Applies to quantities such as flow rate and

temperature and toiattivities such as heating and

reaction.

AS WELL AS Quali ta tive increase

All the design and operating intentions e achieved

along with some additional activity, such as

contamination of process streams.

PART OF Qualitative decreaseOnly some of the design intentions are achieved,

some are not.

REVERSE The logical opposite of

Most applicable to activities such as flow or chemical

reaction. Also applicable to substances, for example,

po son nstea o ant ote.

OTHER THAN Complete substi tut ionNo part of the original intention is achieved - the

original intention is replaced by something else

SOONER THAN Too early or in the wrong order Applies to process steps or actions.

LATER THAN Too late or in the wrong order Applies to process steps or actions.

WHERE ELSE In additional locationsApplies to process locations, or locations in operating

procedures.

Hazop Worksheet

HAZARDANDOPERABILITY STUDYREPORTProject Title:

Project Number; Date:

P&ID Number: Chairman:

Line Number: Study Team:

Guideword

Deviation Cause Consequences Safeguards

Action

Number By DetailsReply

Accepted

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Hazop WorksheetHAZOP ACTION SHEET

Project: Project no: Action no:

Action on: Date for reply:

Description:

Reply:

Review comments:

Accepted/rejected (Leader) Date:

Issued Returned Complete

Return completed form to:


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HAZARD AND OPERABILITYSTUDY REPORT

Project Title: household water supply system

Project Number; 2008-101 Date: 25 Oct 2008

Drawing Number: Myhome-101 Chairman: Mywife

Line Number: Line No 1 ( pipe from water tank

and kitchen tap)

Study Team: MyHusband, Maid, eldest son

Item:KitchenTap Paramter:FlowGUIDE

WORDSDEVIATIONS CAUSES CONSEQUENCES SAFEGUARDS ACTION REQUIRED

REVERSEWater flow

continuously

Valve (kitchen tap)

fails openKitchen flooded none

Install flow control

valve

NO No Flow Pipe BlockedNo water supply

to kitchennone

Install tank cleaning

system

LESS Low flowPipe partially

Blocked

Reduced ater

flow to kitchennone

Install tank cleaning

system

MORE


HAZARD AND OPERABILITYSTUDY REPORT

Project Title: household water supply system

ro ect um er: - ate: ct

Drawing Number: Myhome-101 Chairman: Myhusband

Line Number: Line No 2 (main valve, pipe &

tank)

Study Team: Mywife, Maid, eldest son

Item:WaterTank Paramter:WaterSupplyGUIDE

WORDSDEVIATIONS CAUSES CONSEQUENCES SAFEGUARDS ACTION REQUIRED

MOREMore water than

tanks capacity

House owner forgot

to close water

supply valve

Water tank

overflow, house

flooded

none Install level control ler

NO No water Pipe blocked Tank dry none Install water filter

LessLow water level

in tank

Pipe partially

blocked

Low water

pressure to

bathroom and

kitchen

none Install water filter

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Example 3

Household Water Supply system