hazop method

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Hazard and Operabi l i t y ( HAZOP)St udy

Dr. AA

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HAZOP Fundament al

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A scenari o…

• You and your family are on a road trip by using a car in the middle of the night. You were replying a text message while driving at 100 km/h and it was raining heavily. The car hits a deep hole and one of your tire blows. You hit the brake, but due to slippery road and your car tire thread was thin, the car skidded and was thrown off the road.

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Poi nt s t o ponder

What is the cause of the accident?

What is the consequence of the event?

What can we do to prevent all those things to happen in the first place?

(5 minutes for brainstorming ideas)

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What other possible accidents might happen on the road trip?

Can we be prepared before the accident occurs?

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Can we make i t more syst emat i c?Par amet er Gui dewor d Possi bl e

CausesConsequences Act i on Saf eguar d

Car speed Too f astToo sl ow

Rushi ng Ski dded when emer gency br ake

- Sl ow down- Speed up

- ABS br ake syst em- Saf et y bel t- Ai r bag

Ti r e No t hr eadLess t hr ead

Ti r e t oo ol d, of t en speedi ng and emer gency br eak

Car ski dded - Check f r equent l y- Have spar e t i r e

Wi ndow vi s i bi l i t y

LowVer y l ow

Rai n Cannot see t he r oad

Car l i ght Di mNo l i ght

- St op car- Go t o near est gar age- Use emer gency si gnal

Road Wi t h hol esRocky

Br eaks t he car t i r e

- Put a s i gnboar d- St r eet l i ght s

Tr avel t i me

Ni ghtFoggy

No st r eet l i ght

- Tr avel dur i ng dayl i ght

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• Systematic technique to IDENTIFY potential HAZard and OPerating problems

• A formal systematic rigorous examination to the process and engineering facets of a production facility

• A qualitative technique based on “ guide-words” to help provoke thoughts about the way deviations from the intended operating conditions can lead to hazardous situations or operability problems

• HAZOP is basically for safety

- Hazards are the main concern

- Operability problems degrade plant performance (product quality, production rate, profit)

• Considerable engineering insight is required - engineers working independently could develop different results

What is HAZOP?

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Ori gi n of HAZOP

• Ini t i al l y prepared by Dr H G Lawl ey and associ at es of ICI at Wi l t on i n 1960’ s .

• Subsequent l y C J Bul l ock and A J D Jenni ng f rom ChE Dept . Teesi de Pol yt echni c under supervi si on of T. A. Kl et z appl i ed t he met hod at hi gher i nst i t ut i on ( post - graduat e l evel ) .

• In 1977, Chemi cal Indust ri es Associ at i on publ i shed t he edi t ed versi on.

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Lat er Devel opment - HAZOP

• ICI expanded t he procedure cal l ed HAZARD STUDY st eps 1 t o 6.

• The ICI si x st eps : Proj ect expl orat i on / prel i mi nary proj ect

assessment – t o i dent i f y i nherent hazards of process chemi cal s , s i t e sui t abi l i t y and probabl e envi ronment al i mpact .

Proj ect def i ni t i on – t o i dent i f y and reduce si gni f i cant hazards associ at ed wi t h i t ems and areas , check conf ormi t y wi t h rel evant st andards and codes of pract i ces .

USE CHECK LI STS

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Desi gn and procurement – t o exami ne t he PID i n det ai l f or i dent i f i cat i on of devi at i ons f rom desi gn i nt ent capabl e of causi ng operabi l i t y probl ems or hazards.

Duri ng f i nal s t ages of const ruct i on – t o check t hat al l recommended and accept ed act i ons recorded i n st eps i , i i and i i i i mpl ement ed.

Duri ng pl ant commi ssi oni ng – t o check t hat al l rel evant st at ut ory requi rement s have been acknowl edges and al l i nst al l ed saf et y syst ems are rel i abl y operabl e.


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Duri ng normal operat i on, some t i me af t er st art - up – especi al l y i f any modi f i cat i on been made. To check i f changes i n operat i on has not i nval i dat ed t he HAZOP report of st ep i i i by i nt roduci ng new hazards.

Thi s procedures are adopt ed f ul l y or part l y by many compani es around t he worl d.


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Objective of HAZOP

• For identifying cause and the consequences of perceived mal operations of equipment and associated operator interfaces in the context of the complete system.

• It accommodates the status of recognized design standards and codes of practice but rightly questions the relevance of these in specific circumstances where hazards may remain undetected.

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• HAZOP identifies potential hazards , failures and operability problems.

• Its use is recommended as a principal method by professional institutions and legislators on the basis of proven capabilities for over 40 years.

• It is most effective as a team effort consists of plant and prices designers, operating personnel, control and instrumentation engineer etc.

• It encourages creativity in design concept evaluation.• Its use results in fewer commissioning and operational problems

and better informed personnel, thus confirming overall cost effectiveness improvement.

How and Why HAZOP is Used

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• Necessary changes to a system for eliminating or reducing the probability of operating deviations are suggested by the analytical procedure.

• HAZOP provides a necessary management tool and bonus in so far that it demonstrates to insurers and inspectors evidence of comprehensive thoroughness.

• HAZOP reports are an integral part of plant and safety records and are also applicable to design changes and plant modifications, thereby containing accountability for equipment and its associated human interface throughout the operating lifetime.


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• HAZOP technique is now used by most major companies handling and processing hazardous material, especially those where engineering practice involves elevated operating parameters :

- oil and gas production

- flammable and toxic chemicals

- pharmaceuticals etc

• Progressive legislation in encouraging smaller and specialty manufacturing sites to adopt the method also as standard practice.


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• It emphasizes upon the operating integrity of a system, thereby leading methodically to most potential and detectable deviations which could conceivably arise in the course of normal operating routine

- including "start-up " and "shut-down" procedures

- as well as steady-state operations.

• It is important to remember at all times that HAZOP is an identifying technique and not intended as a means of solving problems nor is the method intended to be used solely as an undisciplined means of searching for hazardous scenarios.

Purpose of HAZOP

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HAZOP - Hazard and operability

HAZOP keeps all team members focused on the same topic and enables them to work as a team

1 + 1 = 3

NODE: Concentrate on one location in the process

PARAMETER: Consider each process variable individually (F, T, L, P, composition, operator action, corrosion,

etc.)GUIDE WORD: Pose a series of standard questions about deviations from normal conditions. We assume that we know a safe “normal” operation.

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HAZOP - Hazard and operability

NODE: Pipe after pump and splitter

PARAMETER*: Flow rate

GUIDE WORD*: Less (less than normal value)

• DEVIATION: less flow than normal

• CAUSE: of deviation, can be more than one

• CONSEQUENCE: of the deviation/cause

• ACTION: initial idea for correction/ prevention/mitigation

A group members focus on the same issue simultaneously

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Question : How can one be certain to identify all possible deviations ?

Answer : No absolute certainty as the study is subjective and 100 % achievement in this context can have no significance. Any individual or corporate effort will yield results directly proportional to the appropriate background experience of those taking part.

However, with the appropriate levels of individual project-related expertise , such a procedure is fully capable of identifying at least 80 % of potential deviations which could rise during normal operation.

Relevant Question About HAZOP

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Separate consideration is demanded for other operating modes, such as commissioning, emergency shut-down procedures and isolation of equipment for maintenance or modification.

Once an installation is endorsed by a properly-conducted HAZOP study, it is these non-steady state circumstances which benefit particularly from the technique throughout the life time of the installation.

' Operability' must also consider the human factors involved as well

as the prediction of equipment behavior.


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Apart from the uniformity of day-to-day activities , hazards which could cause major production interruptions and loss, possibly leading to costly incidents, need to be identified :

• Are there chemicals used in the plant which have not been classified as hazard because they are handled in small quantities, are assumed harmless, or are not considered to have long-term toxic effect upon employees?

• What hazardous materials are transported to or from the site ?

• What routes are taken ?

• What would be the consequences of accidental release?


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• What effluents are generated by the operation being carried out or contemplated ? What regulations require to be honored for their disposal?

• Are chemicals properly packaged & labeled?• Are the consequences of product misuse made absolutely clear?• Have all potential God-made events and man-made incidents (e. g

breaches of security, sabotage, electric power failure ) been considered?

• Are the codes and standards applicable to each facility and relating to its design , sitting and construction complied with? For example, in pressure vessel design.


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Feat ures of HAZOP St udySubsyst ems of i nt erest l i ne and val ve, et c

Equi pment , Vessel s

Modes of operat i on Normal operat i onSt art - up mode Shut down modeMai nt enance /const ruct i on /

i nspect i on mode

Tri gger event s Human f ai l ureEqui pment /i nst rument /component f ai l ureSuppl y f ai l ureEmergency envi ronment eventOt her causes of abnor mal

oper at i on, i ncl udi ng i nst r ument di st ur bance

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Ef f ect s wi t hi n pl ant Changes i n chemi cal condi t i onsChanges i n i nvent oryChange i n chemi cal physi cal condi t i ons

Hazardous condi t i ons Rel ease of mat eri alChanges i n mat eri al hazard

charact eri st i csOperat i ng l i mi t reachedEnergy source exposed et c .

Correct i ve act i ons Change of process desi gnChange of operat i ng l i mi t sChange of syst em rel i abi l i t yImprovement of mat eri al cont ai nmentChange cont r ol syst emAdd/ r emove mat er i al s

Feat ures of HAZOP St udy

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How woul d hazardous Duri ng normal operat i on

condi t i ons det ect ed ? Upon human f ai l ureUpon component f ai l ure In ot her c i rcumst ances

Cont i ngency act i ons Improve i sol at i on

Improve prot ect i on

Feat ures of HAZOP St udy

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Document s Needed f or HAZOP St udy

• For Prel i mi nary HAZOP– Process Fl ow Sheet ( PFS or PFD )– Descri pt i on of t he Process

• For Det ai l ed HAZOP– Pi pi ng and Inst rument at i on Di agram ( P & ID

)– Process Cal cul at i ons– Process Dat a Sheet s– Inst rument Dat a Sheet s– Int erl ock Schedul es– Layout Requi rement s– Hazardous Area Cl assi f i cat i on – Descri pt i on of t he Process

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Bef ore Det ai l ed HAZOP

• The devel opment of t he det ai l ed P&I Di agram i s t he l ast st age of t he process desi gn.

• The devel opment wi l l f ol l ow a normal st andard procedure and i ncl ude t he f ol l owi ng consi derat i ons :– Basi c process cont rol syst em - t hi s i s a c l osed

l oop cont rol t o mai nt ai n process wi t hi n an accept abl e operat i ng regi on.

– Al arm syst em - t hi s i s t o bri ng unusual si t uat i on t o at t ent i on of a person moni t ori ng t he process i n t he pl ant

– Saf et y i nt erl ock syst em - t hi s i s t o st op operat i on or part of t he process duri ng emergenci es .

– Rel i ef syst em - t hi s i s t o di vert mat eri al saf el y duri ng emergenci es .

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P&ID

• A Pi pi ng and Inst rument at i on Di agram - P&ID, i s a schemat i c i l l ust rat i on of f unct i onal rel at i onshi p of pi pi ng, i nst rument at i on and syst em equi pment component s.

• P&ID represent s t he l ast st ep i n process desi gn.

• P&ID shows al l of pi pi ng i ncl udi ng t he physi cal sequence of branches, reducers, val ves, equi pment , i nst rument at i on and cont r ol i nt er l ocks.

• P&ID i s normal l y devel oped f rom process f l ow di agram ( PFD) .

• The P&ID are used t o operat e t he process syst em.• A process cannot be adequat el y desi gned wi t hout proper

P&ID.

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A P&ID shoul d i nc l ude: ( Basi cal l y every mechani cal aspect of t he pl ant wi t h some except i ons)

• Inst rument at i on and desi gnat i ons• Mechani cal equi pment wi t h names and numbers• Al l val ves and t hei r i dent i f i cat i ons• Process pi pi ng, s i zes and i dent i f i cat i on• Mi scel l aneous - vent s , drai ns, speci al f i t t i ngs, sampl i ng l i nes, reducers,

i ncreasers and swagers• Permanent st art - up and f l ush l i nes• Fl ow di rect i ons• Int erconnect i ons ref erences• Cont rol i nput s and out put s, i nt erl ocks• Int erf aces f or c l ass changes• Sei smi c cat egory• Qual i t y l evel• Annunci at i on i nput s• Comput er cont rol syst em i nput• Vendor and cont ract or i nt erf aces• Ident i f i cat i on of component s and subsyst ems del i vered by ot hers• Int ended physi cal sequence of t he equi pment

P&I D

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A P&ID shoul d not i ncl ude:• Inst rument root val ves• cont rol rel ays• manual swi t ches• equi pment rat i ng or capaci t y• pri mary i nst rument t ubi ng and val ves• pressure t emperat ure and f l ow dat a• el bow, t ees and si mi l ar st andard f i t t i ngs• ext ensi ve expl anat ory not es

P&I D

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P&ID and Saf et y

• P&I Di agram– ISA St andard– DIN St andard

• Layers of prot ect i on

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• Procedure in HAZOP study consist of examining the process and instrumentation (P&I) line diagram , process line by process line .

• A list of guide words is used to generate deviations from normal operation corresponding to all conceivable possibilities.

• Guide words covering every parameter relevant to the system under review :i.e. flow rate and quality, pressure, temperature, viscosity, components etc.

• Flowchart for application of HAZOP is shown in figure.

HAZOP St udy Procedure

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Select Line

Select deviation e. g more flow

Is more flow possibleMove on to next deviation

Is it hazardous or does it prevent efficient operation ?

Will the operator know that there is more flow ?

What changes in plant or method will prevent the deviation or make it less likely or protect against the consequences ?

Is the cost of the change justified ?

Agree change (s)Agree who is responsible for action

Consider other causes of more flow

What change in plant will tell him ?

Consider other change(s) or agreed to accept hazard

Follow up to see action has been taken

HAZOP St udy Fl ow Chart

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Gui del i nes f or Di vi si on i nt o Sect i ons

• Choi ces of l i nes – P&ID must be di vi ded l ogi cal l y. Not t oo many sect i ons. Fact ors t o be consi dered :– Each sect i on shoul d cont ai n act i ve

component s, whi ch gi ves ri se t o devi at i ons. E. g pi pi ng whi ch cont ai ns cont rol val ves can gi ve ri se t o f l ow devi at i ons, heat exchangers can cause T devi at i ons.

– Mat eri al s i n sect i on – cont ai n si gni f i cant amount of hazardous mat eri al s .

– Sect i on based on process and st at es of mat eri al s . Onl y 1 process operat i on per 1 sect i on.

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• General gui del i nes :– Def i ne each maj or process component as a

sect i on. Usual l y anyt hi ng assi gned equi pment number shoul d be consi dered a maj or process component .

– Def i ne one l i ne sect i on bet ween each maj or process component .

– Def i ne addi t i onal l i ne sect i ons f or each branches of f t he mai n process f l ow.

– Def i ne a process sect i on at each connect i on t o exi st i ng equi pment .


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• Suppl ement ary gui del i nes– Def i ne onl y one process sect i on f or equi pment

i n i dent i cal servi ce. However, pumps i n di f f erent servi ce wi t h a common spare must be t reat ed separat el y.

– Def i ne onl y one l i ne at t he end of a seri es of component s i f t here are no ot her f l ow pat hs.

– Def i ne onl y one addi t i onal l i ne sect i on i f t here are al t ernat i ve f l ow pat hs, regardl ess of how many branches t here are.


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• Do not def i ne l i ne bet ween maj or equi pment i t ems i f t here are no si ngl e act i ve component s t hat coul d cause devi at i ons.

• Do not def i ne sect i ons f or exi st i ng equi pment t hat i s upst ream of new or modi f i ed equi pment . Address mal f unct i ons of such upst ream equi pment as devi at i ons i n t he new or modi f i ed equi pment .


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GUIDE WORDS *

POSSIBLE CAUSES DEVIATION ( FROM DESIGN AND/OR OPERATING INTENT )

CONSEQUENCES

ACTION(S) REQUIRED OR RECOMMENDEED

HAZOP Study Procedure

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NONE No forward flow when there should beMORE More of any parameter than there should be,

e.g more flow, more pressure, more temperature, etc.

LESS As above, but "less of" in each instancePART System composition difference from what it

should beMORE THAN More "components" present than there should

be for example, extra phase, impuritiesOTHER What needs to happen other than normal

operation, e.g. start up,shutdown, maintenance

Guide Words

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NONE e.g., NO FLOW caused by blockage; pump failure; valve closed or jammed : leak: valve open ;suction vessel empty; delivery side over - pressurized : vapor lock ; control failure

REVERSE e.g., REVERSE FLOW caused by pump failure : NRV failure or wrongly inserted ; wrong routing; delivery over pressured; back- siphoning ; pump reversed

MORE OF e.g., MORE FLOW caused by reduced delivery head ; surging ; suction pressurised ; controller failure ; valve stuck open leak ; incorrect instrument reading.

Guide Words

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MORE OF MORE TEMPERATURE, pressure caused by external fires; blockage ; shot spots; loss of control ; foaming; gas release; reaction;explosion; valve closed; loss of level in heater; sun.

LESS OF e.g., LESS FLOW caused by pump failure; leak; scale in delivery; partial blockage ; sediments ; poor suction head; process turndown.

LESS e.g., low temperature, pressure caused by Heat loss; vaporisation ; ambient conditions; rain ; imbalance of input and output ; sealing ; blocked vent .

PART OF Change in composition high or low concentration of mixture; additional reactions in reactor or other location ; feed change.

Guide Words

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MORE THAN Impurities or extra phase Ingress of contaminants such as air, water, lube oils; corrosion products; presence of other process materials due to internal leakage ; failure of isolation ; start-up features.

OTHER Activities other than normal operation start-up and shutdown of plant ; testing and inspection ; sampling ; maintenance; activating catalyst; removing blockage or scale ; corrosion; process emergency ; safety procedures activated ; failure of power, fuel, steam , air, water or inert gas; emissions and lack of compatibility with other emission and effluents.

Guide Words

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HAZOP STUDY REPORT FORMTITLE :

Sheet 1 ofLINE 1 :

DEVIATIONCAUSES CONSEQUENCES EXISTING PROVISIONS ACTIONS, QUESTIONS OR

RECOMMENDATIONS

HAZOP Study Form

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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

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

• Provision for maintenance.

HAZOP Study

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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 is very time consuming and can be laborious with a tendency for boredom for analysts.

• It tends to be hardware-oriented and process-oriented, although the technique should be amenable to human error application.

• It tends to generate many failure events with insignificance consequences and generate many failure events which have the same consequences.

• It stifles brainstorming although this is not required at the late stage of design when it is normally applied.

• HAZOP does not identify all causes of deviations and therefore omits many scenarios.

Weakness of HAZOP

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• It takes little account of the probabilities of events or consequences, although quantitative assessment are sometime added. The group generally let their collective experiences decide whether deviations are meaningful.

• HAZOP is poor where multiple-combination events can have severe effects.

• It tends to assume defects or deterioration of materials of construction will not arise.

• When identifying consequences, HAZOP tends to encourage listing these as resulting in action by emergency control measures without considering that such action might fail. It tends to ignore the contribution which can be made by operator interventions

Weakness of HAZOP

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Managi ng HAZOP

How to manage HAZOP

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Prel i mi nary HAZOP Exampl e

TC

Cooling Coils

MonomerFeed

Cooling Water to Sewer

Cooling Water In

Thermocouple

Refer to reactor system shown.

The reaction is exothermic. A cooling system is provided to remove the excess energy of reaction. In the event of cooling function is lost, the temperature of reactor would increase. This would lead to an increase in reaction rate leading to additional energy release.

The result could be a runaway reaction with pressures exceeding the bursting pressure of the reactor. The temperature within the reactor is measured and is used to control the cooling water flow rate by a valve.

Perform HAZOP Study

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Prel i mi nary HAZOP on React or - Exampl e

Guide Word Deviation Causes Consequences Action

NO No cooling Temperature increase in reactor

REVERSE Reverse cooling flow

Failure of water source resulting in backward flow

MORE More cooling flow

Instruct operators on procedures

AS WELL AS Reactor product in coils

Check maintenance procedures and schedules

OTHER THAN Another material besides cooling water

Water source contaminated

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Prel i mi nary HAZOP on React or – Answer


NO No cooling Cooling water valve malfunction

Temperature increase in reactor

Install high temperature alarm (TAH)

REVERSE Reverse cooling flow

Failure of water source resulting in backward flow

Less cooling, possible runaway reaction

Install check valve

MORE More cooling flow Control valve failure, operator fails to take action on alarm

Too much cooling, reactor cool Instruct operators on procedures

AS WELL AS Reactor product in coils

More pressure in reactor Off-spec product Check maintenance procedures and schedules

OTHER THAN Another material besides cooling water

Water source contaminated

May be cooling inefffective and effect on the reaction

If less cooling, TAH will detect. If detected, isolate water source. Back up water source?

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Case St udy – Shel l & Tube Heat Exchanger

• Usi ng rel evant gui de works, perf orm HAZOP st udy on shel l & t ube heat exchanger

Processfluid

Cooling water

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HAZOP on Heat Exchanger – Answer 1


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 l ine

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 – Answer 2


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 lineInstall TAH

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

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HAZOP - Hazard and Operability

HAZOPNodes

Parameters

Guide words

Consequence

Deviation

All of these terms! This stupid table!I hate HAZOPS. Why don’t we just

learn the engineering?

ATTITUDE CHECK

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I suppose that I should have done that

HAZOP Study!

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HAZOP - Hazard and Operability

Without HAZOP

How will you focus all members of a team on the key issues in a systematic manner?

You are responsible for the

safety team.

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Case St udy

Case study hydrogen plant

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Sampl e Answers

result HAZOP reactor.doc

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HAZOP Management

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What is required?

• Define objectives and scope – define TOR and scope of work.•To new design – applied to a detailed design.•To existing design – identify hazards not previously identified probably because not being HAZOPED.•To plant modification

• Select team members. Two types of person needed :•Detailed technical knowledge of the process.•Those with knowledge and experience of applying highly structured, systematic HAZOP approach.

Planning for HAZOP Study

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• Prepare f or t he st udy. Need suf f i c i ent i nf ormat i on :

• Pr ocess Fl ow Sheet ( PFS or PFD )• Pi pi ng and I nst r ument at i on Di agr am ( P & I D )• Pr ocess Cal cul at i ons• Pr ocess Dat a Sheet s• I nst r ument Dat a Sheet s• I nt er l ock Schedul es• Layout Requi r ement s• Hazar dous Ar ea Cl assi f i cat i on • Oper at i ng i nst r uct i ons

Pl anni ng f or HAZOP

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• Prepare f or t he st udy. Need suf f i c i ent i nf ormat i on :

• Saf et y pr ocedur es document s• Rel i ef / vent i ng phi l osophy• Chemi cal i nvol ved• Pi pi ng speci f i cat i ons• Pr evi ous HAZOP r epor t


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• Carry out t he st udy• Record t he resul t s ( may need a

secret ary)• Fol l ow- up of act i ons not ed

– f i nal report cont ai n resol ut i on of al l recommended act i ons

– must appoi nt someone as l eader t o check progress of act i on

– t eam may meet agai n i f answers t o quest i ons do not si mpl y l ead t o an act i on

– t eam may meet agai n i f s i gni f i cant desi gn changes i n i nt eri m report

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Team Charact eri st i cs

– Members share common obj ect i ves.– Everybody cont ri but es and knows hi s/her

rol es , not l eader dependent t oo much.– Each members val ues and respect s cont ri but i on

of ot hers.– Members l earn whi l e t hey work.– Over a peri od of t i me, i ndi vi dual

cont ri but i on l evel are more or l ess equal .– Di sagreement are worked t hrough by

di scussi on.– The use of vot i ng procedures i s spari ng and

normal l y onl y l ast resort i f hi ghl y necessary.

– Members enj oy t eam meet i ngs.

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Quest i oni ng Techni ques

• Open quest i ons– Hel p person bei ng asked t o t hi nk – use

words how, what and why.

• Cl osed quest i ons– To f ocus on an i ssue or probl em. St art

wi t h words who, when, where.– Requi red answer yes or no onl y.

• Quest i on mi x– Mi x bet ween open and c l osed quest i ons.

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• Thi ngs t o avoi d– Ambi guous or vague quest i ons.– Doubl e barel l ed/mul t i pl e quest i ons.– Long compl i cat ed quest i ons.– Int errogat i on t ype of quest i ons.– A l oaded quest i ons – i mpl i ed j udgement .

Quest i oni ng Techni ques

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HAZOP leader

• Plan sessions and timetable• Control discussion• Limit discussion• Encourage team to draw conclusion• Ensure secretary has time for taking note• Keep team in focus• Encourage imagination of team members• Motivate members• Discourage recriminations• Judge importance issues

Responsi bi l i t y of HAZOP Team Members

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Checkl i st f or HAZOP Leader

• Al ways prepare st udy program i n advance.

• Agree on t he f ormat or f orm t o be used.

• Prepare f ol l ow up procedures.• Bri ef members about HAZOP duri ng

f i rst meet i ng.• St op t he t eam t ryi ng t o redesi gn

t he process.• HAZOP i s a t eam exerci se. Do not

l et anybody ( i ncl udi ng t he l eader hi msel f t o domi nat e) .

70

Checkl i st f or HAZOP Leader

• If conf l i c t ari ses , handl e wi t h care.

• Avoi d l ong di scussi ons by recordi ng areas whi ch need t o be resol ved out si de meet i ng.

• Leader must be st rong, yet di pl omat i c .

• Speak cl earl y. Make you poi nt .• Bet t er have experi ence worki ng as

t eam member previ ousl y.• Do not ski p anyt hi ng…. some t i me

smal l t hi ngs may cause bi g acci dent .

71

HAZOP Secretary

• Take adequate notes• Record documentations• Inform leader if more time required in taking notes• If unclear, check wording before writing• Produce interim lists of recommendations• Produce draft report of study• Check progress of chase action• Produce final report


72

Process Engineer

• Provide a simple description• Provide design intention for each process unit• Provide information on process conditions and design conditions• Provide a simple description• Provide design intention for each process unit• Provide information on process conditions and design conditions


73

Mechanical Design Engineer

• Provide specification details• Provide vendor package details• Provide equipment and piping layout information

Instrument Engineer

• Provide details of control philosophy• Provide interlock and alarm details• Provide info on shutdown, safety features


74

Plant Engineer or Manager• Provide information on compatibility with any existing adjacent

plant• Provide details of site utilities and services• Provide (for study on existing plant) any update on maintenance

access and modifications

Shift Operating Engineer or Supervisor• Provide guidance on control instrumentation integrity from an

operating experience view point• Provide (for study on existing plant) information on plant stability

at the specified control parameters• Provide information on experienced operability deviations of

hazard potential


75

Chemist

• Provide details of process chemistry• Provide details of process hazards (polymerisations, byproducts,

corrosion etc)

Project Engineer

• Provide details of cost and time estimation and also budget constraints.

• Ensure rapid approval if required


hazop method

Technology

car tire thread

safety hazards

road trip

check lists

operating problems

systematic technique

significant hazards

operability problemshazop