15 30 - 2555 . 167

: Fault Tree Analysis: Hazard Identification Techniques

for Preventing Work Accidents

*

*

(fault tree analysis : FTA)

(basic event)

Boolean

4

(top event)

(cut sets)

FTA

failure modes and effects

analysis(FMEA)hazardandoperabilityanalysis(HAZOP)

:

. 15 30 - 2555 168

Abstract

Accidentinvestigationisanactivityofadvancedsafetymanagementwhichhelps

us know only some causes of accidents. The use Fault Tree Analysis (FTA) technique

couldsearch forcausesofaccidentsorsystemfailures indetailsand leadustoknow

basic event. FTA presents failure logic using Boolean logic model to find out rational

causes of problems or failures which comprises of 4 processes as follows: setting or

selecting top event, constructing Fault Trees diagram, finding the route through a tree

betweenaneventandaninitiatorinthetreecalledacutsetandsettingpriorityofbasic

eventsforconsideringtosolveproblemsonthenextstep.Byusingthistechnique, the

analysis team should have knowledge and well understand in the entire processes

relatingproblemsor failures.OnlyFTA technique, thismightnotbesufficient, it should

combinewith other techniques for analysis such as failuremodes and effects analysis

(FMEA)andhazardandoperabilityanalysis(HAZOP)etc.

Keywords:Faulttreeanalysis(FTA),hazardidentification,workaccident

2..2549-2551

(

. 2549)

15 30 - 2555 . 169

( .

2551)

fault tree analysis (FTA)

12 (.

2543)

FTA Bel l

TelephoneLaboratories..1962

US Air Force

minuteman

Boeing

Witkin Stephen (Rel iaSoft

Corporation. 2000, W.E.Vesely and etc.

1981)FTA

hazard and operability

study (HAZOP) failure modes and

effects analysis (FMEA)

/

FTA

5 (pilot

plant operation)

(detailed engineering)

(routineoperation)

(expan-

sion modification)

/ (incident investigation)

(.2549:1-12)

FaultTreeAnalysis

Fault Tree Analysis

Fault tree analysis

(top-downdiagram)

(top event)

(intermediate event)

(basicevent)

Boolean

AND gates OR gates

FTA

(topevent)

/

. 15 30 - 2555 170

(cutsets)

(minimal cut set; mcs)

(1)

And Gate

(output)

(

) (

)

(

.2552:87-141)2

ORGate

4

2

INHIBIT Gate

(condition)

(restriction)

(polyurethane)

280

2

DELAYGate

2

TRANSFER Event

15 30 - 2555 . 171

UNDEVELOPED Event

BASIC Event

/

(human

error)

3

(.

2552:87-141)2

EXTERNAL Event

ANDGate

OR

Gate

INHIBIT

Gate

DELAY

Gate

TRANSFER

Event

UNDEVELOPE

DEvent

BASIC

Event

EXTERNAL

Event

1FTA

. 15 30 - 2555 172

FTA (.2550 ;

.2545;.2546;

Americaninstituteofchemicalengineering.

1992Reliability engineering resource.

2000)

1

280C

/

2ANDgate,ORgate,INHIBITgateBASICevent

/

3

(what) (where) (when)

FTA

.......whatifanalysis

15 30 - 2555 . 173

2

(fault event)

Boolean

(OR)

(AND)

,

2

/ (state of equipment

fault)

(state of system fault)

(3)

3

matrixforresolvinggates4

1. ( A, B, C.)

gate gate

( 1, 2, 3 ......)

4

. 15 30 - 2555 174

/

(TopEvent)

3

4

Boolean

/

/

//

3

:~525

~1,200

A

BC

1

4

3

()

2

D

6

5

15 30 - 2555 . 175

2. matrix

(matrixforresolvinggate)

(gate)(A)

(A)

matrix

ANDgate

OR

gate

5

3. matrix

5

4

3.1

(polystyrene)

/

~272

3.2

/

3.3

272

3.4

4.

. 15 30 - 2555 176

4.1

4.2

(human error)

/

(activeequipment failure)

/

Fault

TreeAnalysis

matrix

/

FMEA HAZOP

matrix

15 30 - 2555 . 177

matrix:gateA

A

gateAgateB,CD

AB C D

gateBevent12gateCD

AB1 C D 2

gateCevent34gateD,event12

event4gateC

AB1 C3 D 2

1 4 D 2

gateDevent56event1,32

event6gateD

AB1 C3 D5 2

1 4 D 2

1 3 6 2

gateDevent56event1,42

event6gateD

AB1 C3 D5 2

1 4 D5 2

1 3 6 2

1 4 6 2

event

AB1 C3 D5 2=1235

1 4 D5 2=1245

1 3 6 2=1236

1 4 6 2=1246

5matrix/

. 15 30 - 2555 178

(topevent)

(intermediate event)

(basic event) gate

2

/

matrix

(human error)

/

(active equipment failure)

/

15 30 - 2555 . 179

.(2543)

. :

.

. (2552) 3

.

, . 87-141. :

.

. (2549)

. 1-12. :

.

. (2549) Sa 01/F01 /; 3

2549.:.

.(2551)SHE004;102551.

:.

. (23 2552)

.

[Online] Available http://www.eit.or.th/content.php?&option=content&id=317 (18

2553)

. (2550) Industrial Safety Technology.

:.

.(2545).:

.

. (2546) 3.

[Online]Availablehttp://www.thaifactory.com/TM/risk3.pdf(182553)

. 15 30 - 2555 180

American Institute of Chemical Engineering. (1992) Selecting Hazard Evaluation

TechniquesGuidelinesforHazardEvaluationProcedure.2nded.NewYork:

CenterforChemicalProcessSafety.

American Institute of Chemical Engineering. (1992) Overview of Hazard Evaluation

TechniquesGuidelinesforHazardEvaluationProcedure.2nded.NewYork

:CenterforChemicalProcessSafety.

AmericanInstituteofChemicalEngineering.(1992)UsingHazardEvaluationTechniques

GuidelinesforHazardEvaluationProcedure.2nded.NewYork:Centerfor

ChemicalProcessSafety.

Reliability engineering resource. (2000) Fault Tree Analysis. Tucson :ReliaSoft

Corporation. [Online]Available:http://www.weibull.com/basics/fault-tree/index.htm.

(182553)

W.E. Vesely, F.F. Goldberg and N.H. Roberts. (1981) Fault Tree Handbook. 1st ed.

Washington,DC:U.S.NuclearRegulatoryCommission.