w

1. Identify main hazards

2. Identify critical tasks

3. Understand the tasks

4. Represent critical tasks

5. Identify human failures and performance influencing

factors (PIFs)

6. Determine safety measures to control human failures

7. Review effectiveness of process

Main inputs Main outputs

Existing safety reports and risk assessmentsSite layouts and descriptions

Existing safety reports and risk assessmentsProcedure manuals, discussions with staff

Written procedures, checklists, job aidsInterviews, interactive observation

Outputs from step 3Methods such as HTA

Task representation from step 4Methods such as human HAZOP

Outputs from step 5Hierarchy of potential risk controls

Trials of SCTAExperience from mature use of SCTA

List of MAHsMajor hazard operations and areas of site

List of safety critical tasksPrioritisation of such tasks when many MAHs

Full understanding of safety critical tasksWho does what, when, in what sequence, etc.

Breakdown of tasks in tables or diagramsSufficient detail for analysis in steps 5 and 6

List of potential human failures & consequencesPIFs and current safety measures

List of potential additional safety measuresALARP demonstration and documentation

Recommendations for improved SCTA qualityRecommendations for improved resource use

Safety

Culture

Interactive observation

Safety

CultureCTA data collection

Safety

Culture

Interactive observation

Safety

CultureCTA data collection

LAH

LSH

LI

To Process

No

Yes

ConsequenceFire Automatic Manual Fire fighting

Fire detected shutdown shutdown successful Escalation preventedYes Yes Yes

Limited escalation

NoEscalation prevented

No Yes YesLimited escalation

NoEscalation prevented

No Yes

Major escalationNo

Major escalationNo

MAH e.g. loss of

containment

Firefighting

Shutdown

Detection

HF failureHF barrier or recovery measureTechnical barrier or recovery measure

Potential causes Potential consequences

Enhanced smoke/ flame detection

Updated procedure for manual ESD

Maintenancefailures

Start up operationsfailure

Improved PTW system

Labelling of controls

Equipment isolation

1. Identify main hazards

2. Identify critical tasks

3. Understand the tasks

4. Represent critical tasks

5. Identify human failures and PIFs

6. Determine safety measures to control human failures

7. Review effectiveness of process

Populartechniques

HAZOPsFTA ETA

Walk throughTalk through

HTA

Human HAZOPBow tie

Human HAZOPBow tie

Safety report/ Safety caseIntegration