1988: Piper Alpha Oil Rig Ablaze

CHEN 655 Project:Syed QuraishyTasmia Tahsin Priyanka

Piper Alpha-Location

At around 110 miles north-east of Aberdeen in the North Sea.

Claymore and Tartan were the two other platforms connected to Piper which were also operated by Occidental.

http://www.brighthubengineering.com/marine-history/116049-piper-alpha-oil-rig-disaster

Piper Alpha-Background

• Owned by a consortium consisting of

-Occidental Petroleum (Caledonia)

-Texaco Britain Ltd

-International Thomson Plc

-Texas Petroleum Ltd

• Oil Production in 1976 about 250,000 barrels per day increasing to 300,000 barrels later.

• In 1980 a gas recovery module was installed .• Production declined to 125,000 in the year

1988.

Piper Alpha-Background

• The production deck level consisted of four Modules:

Module A: Well head

Module B: Oil Separation

Module C: Gas compression

Module D: Power generation and Utilities

Piper Alpha-Background

Piper Alpha Platform: West Elevation

(Lee’s Loss Prevention in Process industries, Volume 3)

Piper Alpha Platform: Production deck on 84 feet level

Piper Alpha-Timeline

Incident Investigation1 hr. 35 min before disaster:

All gas alarm came from module C

Captain in one of the nearby ship had seen a blue flame coming underneath the module C

Convinced the investigator that module C was starting point of the explosion

Analyzing 3 products of Piper Alpha they were confirmed that condensate started the fire.

Incident Investigation Analyzed the pattern of the gas

alarm & suspected a condensate release in the eastern end of module C.

Only source of condensate in module C is two PSV’s; designed to withstand twice the operating pressure.

PSV-504 was taken out for a maintenance work, replaced by a blind flange/metal disk

Incident Investigation Workers had installed the metal disk by

hand tight. PSV-504 was connected with a condensate

pump which was shut down for an overhauling job.

Standby pump (Pump-B) tripped that night and the lead operator (unaware about the PSV maintenance work) had swapped the pump & introduced condensate for priming before startup.

Later when they had started the pump the leak was larger and triggered multiple gas alarms including the High gas alarm

1 hr. 30 min before disaster:

Module C was protected by fire walls designed to resist intense flames up to 6 hrs. but not explosion proof.

Destroyed the fire panels of the fire walls which had flown like projected missiles.

Damaged another condensate pipeline in module B.

This leak aided a second explosion which was an oil explosion resulted in an evanescent fire ball.

Incident Investigation

Incident Investigation1 hr. 10 min before disaster:

Colossal explosion from the bottom of module B had shaken the platform

Oil was dripping below the module B did not dripped directly to the sea but it settled

Divers placed rubber matting over the gratings to avoid the sharp edge on their bare feet

Dripped oil had formed a small pool and this pool fire had heated up a high pressure gas line from Piper alpha to another rig named Tartan.

The pool fire, weak metal, high pressure heated up gas caused the huge explosion and around 150m (as per Cullen Report) fire ball

Incident Investigation HP gas pipeline to Claymore destroyed Living quarter dislodged to the sea with

all the crew

Failure Analysis & Mitigation

PTW System• Multiple PTW should be kept at a common place• Proper hand over between shifts• Effective site auditing regarding specialized permit• Appropriate equipment specific isolation procedure

Fire wall and Layout

• Conducting a design safety review before any modification and analyzing the requirement of passive fire protection (blast proof walls) due to the new modification.

• Conducting Explosion Overpressure Study to check the extent to which the walls could withstand explosion

Failure Analysis & Mitigation

Automatic water deluge

system• Putting the critical safety equipment always on

automatic mode

Production-Safety Conflict

• People > Environment > Asset > Revenue

OSHA PSM Elements Failure

The 14 key elements of OSHA PSM are as follows: Employee participation Process safety information Process hazard analysis (PHA) Operating procedures Training Contractors Pre-start up safety review Mechanical integrity Hot work permits Management of change Incident investigations Emergency planning and response Audits Trade secrets

OSHA PSM Elements Failure

The 14 key elements of OSHA PSM are as follows: Employee participation Process safety information Process hazard analysis (PHA) Operating procedures Training Contractors Pre-start up safety review Mechanical integrity Hot work permits Management of change Incident investigations Emergency planning and response Audits Trade secrets

Accidents and disasters are common events in chemical, oil & gas, manufacturing, and nuclear industry.

Piper Alpha Disaster was initiated & propagated by faulty actions of human.

In our study of this incident we have focused on Human Error.

Our Approach

Human Error“Departure from acceptable or desirable

practice on the part of an individual that can result in unacceptable or undesirable results”1

Intentional & unintentional manmade mistakes that cause injury to people, environment pollution, economical loss and reputational damage.

It is a concept for explaining breakdowns, accidents or other inadvertent consequences .

1Bea, Holdsworth, and Smith, “Human and Organization Factors in the Safety of Offshore Platforms

Human error includes:

Failing to execute or omitting a task Accomplishment of the task inaccurately Performing an additional or non-required

task Performing tasks out of sequence Failing to perform the task within time limit

linked with it Failing to respond effectively to an

emergency

Human Error

Human Error Classification

Unsafe Acts

Intended Action

unintended Action

Slip

Laps

Mistake

Violation

Attentional FailureIntrusionOmissionReversal

MisorderingMistiming

Memory FailureOmitted Planned items

Place-losingForgetting intensions

Rule-based MistakesMisapplication of good rule

Application of bad ruleKnowledge-based Mistakes

Many variable forms

Routine ViolationExceptional ViolationArt based mistakes

Fig. 1: Unsafe Acts taxonomy (Reason 1990)

Slips: Errors associated with the execution of faulty action.

Lapses: Errors is caused by memory failure.

Mistakes: Error occurs perfect execution of a task but wrong planning.

Violations: Errors associated with deliberately avoiding organizational rules and regulations.

Human Error Classification

Human Error Classification

Human Error

Handling Error

Maintenance Error

Assembly Error

Design Error

Installation Error

Inspection Error

Operator Error

Control Error

Fig. 2: Human Error in Different Phase of a Project

Contributors to Human Error

Performance requirements that exceed human capability

Design that promotes fatigue Inadequate facilities or information Difficult/ Dangerous/ Unpleasant/

Repetitive tasks Tasks at odds with the person's aptitude Stress, Illness, Sleep Deprivation, Injury.

Human Error Management Reduce error vulnerabilities to tasks/task

elements Determine, asses & eliminate error

producing factors within the workplace Identify organizational factors that create

error producing conditions within the individual, team, task & workplace

Enhance error detection Increase the error tolerance of the system Improve the organization resistance to

human fallibility

HEART: Human Error Assessment & Reduction Technique

Established by J.C. Williams (1986)Procedural technique that attempts to

calculate human error. Data based structured approach to human

error quantification Uses its own values of reliability & also

“factors of effect” for a certain number of error producing conditions

Start

Analyze task by using HTA

Take the first/next task step from the

HTA

Assign a HEART generic category to

the task step in question

Assign a nominal human error

probability (HEP) to the task step in

question

Select any relevant error producing

conditions (EPC’s)

Take the first/next EPC

Determine the assessed proportion of effect of the EPC on the nominal HEP

Are there any more EPC’s?

YN

Calculate the final HEART HEP for the

task step in question

Are there any more task steps?

NY

Stop

HEART Methodology

Step 1: Categorized task Analysis (HTA)Step 2: The HEART Selection ProcessStep 3: Classification of task unreliabilityStep 4: Identifying Error Producing Conditions (EPC)Step 05: Assessed proportion of effectStep 06: Explanation of remedial measuresStep 07: Documentation

Human Errors in Piper AlphaPerforming a maintenance work without

following appropriate procedureFaulty warning system & read out problems

in the control board panel due to design of the panels or action of board operator

Put the automatic (electricity driven) firefighting pumps turned off

Philosophy of production first rather than safety first

Action of a less trained people as major decision maker

Assumed ScenarioA key overhauling work, already in backlog No practice of cross referencing between

works Possibility weather condition changeComplacent attitude in the auditing &

inspection practice. Non redundant methanol system (hydrate

inhibitor) needs troubleshootingRecently promoted OIM having no

experience in managing crisis condition as an incident commander.

General task category

Type of task (E) Routine, highly practiced, rapid task Involving relatively low level of skill

Nominal Human Unreliability 0.02

Error Producing ConditionsEPC HEART

effect (E)

Assessed Proportion

(P)

Assessed effect

A.E=((E-1) x P) + 1

No means of conveying spatial

and functional information to

operators(in this case

maintenance crew) in a form

which they can readily

assimilate

X 8.0 0.15 2.05

The need to transfer specific

knowledge from task to task

without loss

X 5.5 0.2 1.9

Little or no independent

checking or testing of output

X 3.0 0.5 2

Ambiguity in the required

performance standards

X 2.5 0.35 1.525

A need for absolute judgments

which are beyond the

capabilities/experience of the

performer

X 1.6 0.25 1.150

No obvious way to keep track of

progress during an activity

X 1.4 0.5 1.2

Human Error Probability

Nominal likelihood of failureP = Calculated Human Error Probability (HEP) is

nearly 33% for this particular task

Remedial MeasuresSpatial & Functional Incompatibility Such incompatibilities should not occur. If there is any

doubt expert opinion should be obtained to run the task in

appropriate manner

Knowledge Transfer Reliance should not be placed on operators transferring

their previous knowledge without loss of precision or

meaning-if such perfect transfer is required suitable job aids

should be provided as reference.

Inadequate Checking When high reliability is paramount, independent checking on

a proper accuracy level by people & systems that do not

have any vested interest in the success/failure of an

individual. Blame game is strictly prohibited.

Ambiguity It needs to be ensured that all the performers of a particular

task are well aware of the codes & standards. There should

not be any chance of relying on substandard information

Requirement of absolute judgment Task performer should not be placed in the position of

taking decision about issues which are outside the span of

their experience. Task analysis will help to figure out the

time when this sort of situation arises & management should

have contingency plan. Brain storming or problem solving

sessions can help to tackle this bizarre condition.

Lack of progress tracking Job aids (checklist/electronic mimic) need to be supplied in

order to ensure that performers do not go out of step with

the task in hand.

HEART at a glance

HEART method was used for error probability assessment & error reduction.

HEART provided valued awareness regarding industrial parameter

Aided to figure out appropriate defenses against human error in both qualitative & quantitative level.

AftermathImmediate wide ranging assessments of the installation

and management system carried.Official public inquiry of the disaster was done by Lord

Cullen came up with 106 recommendations. The Offshore Installations (Safety Case) Regulations

came into effect 1992The Offshore Installation and Pipeline Works

(Management and Administration) Regulations 1995 The Offshore Installations (Prevention of Fire and

Explosion, and Emergency Response) Regulations 1995 (PFEER)

The Offshore Installations and Wells (Design and Construction, etc) Regulations 1996

Survivors Psychology

Professor David Alexander carried out a study on the long-term psychological and social effects of Piper Alpha on the survivors.

Around 70% survivors had psychological and behavioral symptoms of post-traumatic stress disorder.

They had difficulty in finding employment.Employers regarded Piper Alpha survivors as

Jonahs – bringers of bad luck.Family members of the dead and survived victims

suffered psychological and social problems.

Piper Alpha Today

• Platform that used to produce 10 percent of the North Sea’s oil , today only a wreck buoy of it is all that is visible.

• A memorial sculpture showing three oil workers was founded in the Rose Garden within Hazlehead Park in Aberdeen.

• A scholarship was launched on April 20th 2011 by Industry Skills and Safety Body OPTIO as a tribute to the heroes of Piper Alpha who lost their lives.

• “Pound for Piper Memorial” was launched on the 28th of May 2012 to raise £1m for maintenance of the Piper Alpha Memorial garden.

• A three-day event to be held at Aberdeen which will be chaired by Oil & Gas UK chief executive, Malcolm Webb to mark 25 years of Piper Alpha disaster

This Presentation is dedicated to all the

survivors- “When I stand before thee at the day's end, thou shalt see my scars and know that I had my

wounds and also my healing.”-Rabindranath Tagore

THANK YOU