Safety+Lecture+1

ECE 4353

Chemical Process Safety

Introduction to Process Safety

(Lecture 1)

Last Updated:17 September 2015 © LMS SEGi education group 2

LEARNING OBJECTIVES

Explain the government-industry’s responsibility for health and

safety

Evaluate the nature of hazards posed by materials which are

flammable, toxic and reactive

Analyze different scenario using appropriate source models.

Identify and quantify common industrial methods to control

hazards.

Carry out a simple QRA

Last Updated:17 September 2015 © LMS SEGi education group 3

Lecture 1

1.1 Importance of process safety

1.2 Risk Assessment

1.3 Acceptable risks

1.4 Risk Management

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Process safety focuses on

preventing fires, explosions and accidental chemical releases in chemical process facilities, plants or production facilities.

Uses various tools / techniques

Eg. Swiss cheese model

LOPA (Layers of Protection Analysis)

QRA (Quantified Risk Assessment)

1.1 IMPORTANCE OF PROCESS SAFETY



SafetyAudits

‘What-if’ analyses

FMEAFailure Mode Event &Analysis

Fault Tree Analysis

HAZOPHazard & Operability Studies

Event TreeAnalysis

PROCESS SAFETY TECHNIQUESCheck list

PROCESS HAZARD ANALYSIS

LOPALayer of Protection Analysis


Process safety techniques employsystematic methods to:• Evaluate a process system• Identify process hazards



On the night of December 2, 1984, the factory owned by theU.S. multinational Union Carbide Corporation accidentally leaked methyl isocyanate and other highly toxic gases into the air, killing thousands of largely poor Indians in the neighborhoods nearby.



• Estimated 3000 people died from

thethe sameeffects of the poisonous gas on

night of the disaster.• An estimated 20,000 – 30,000 others havesince died from the

• more than 600,000 –

effects of the

900,000

people

leak

beingdeadly gas cloud thatexposed to the

night. Thegasesground, causing victims throats

stayed low to theand eyes

inducing nausea, and manyto burn, deaths.


Bhopal:World's worst industrial incident.






The abandoned former Union Carbide pesticide plant in Bhopal, India.





• An explosion and resultingdestroyed Piper Alpha

oil and gason 6 Julyfires

1988.

• Totalinsured loss was about £1.7

billion (US$3.4 billion).

crew; 165 out of• The accident killed 167 220crew members, plus two crew from thestandby vessel Sandhaven.

attributed mainly to• The accidenthuman error,

wasand was a major eye opener

industry regardingto thesafety

offshoreissues.


Piper Alpha:Worst Offshore disaster.


• Following the tragedy, an inquiry intothe accident commenced in Novembe

r1988

headed by Lord Cullen.was conducted in two parts.• The inquiry

The first part studied the causes of thesecond part presentedto avert future

tragedy and the recommendations occurrence.• It presented 106 recommendations forchanges to North Sea safety procedures.



in the offshore industry withsafety management, regulation

regard toand

training. A majorresponsibility for

impact wasNorth Sea safety

of Energyshifting from to the Health

the Department andSafety Executive.

Also, automatic shut-down valves wereon rigs, to starve a firemade mandatory

of fuel.

1.1 IMPORTANCE OF PROCESS SAFETY• The inquiry brought about great changes


What is the difference between RISK and

HAZARD?

<video on Risk vs Hazard>

RISK vs HAZARD


Risk = Severity x LikelihoodSeverity= ConsequencesMagnitude of LossInjuries, Fatalities, $$ Losses, Environmental Impact

Likelihood= ProbabilityChance of Failure

RISK


• Risk increases if either likelihood or severity [magnitude of loss] increasesprovided the other component does notdecrease proportionally.

RISK


Importance of Risk Assessment• Identify hazards• Analyse or evaluate the risk associated with

thathazard.

• Determine appropriate ways to eliminate orcontrol the hazard.

1.2 RISK ASSESSMENT


What is Risk Assessment?• Identify the hazards• Assess the risks by considering

the severity and likelihood of bad outcomes.

• If the risks are not sufficiently low, then additional controls or alternate methods must be applied.

1.2 RISK ASSESSMENT


Why is Risk Assessment Important?• Integral part of a good occupational health

and safety management plan.• Create awareness of hazards and risks.• Identify who may be at risk (employees,

cleaners, visitors, contractors, the public, etc).• Determine if existing control measures are

adequate or if more should be done.• Prevent injuries or illnesses when done at the

design or planning stage.• Prioritize hazards and control measures.

1.2 Risk Assessment


What is the goal of Risk Assessment?• The aim of the risk assessment

process is to remove a hazard or reduce the level of its risk by adding precautions or control measures, as necessary.

• Create a safer and healthierworkplace.

1.2 RISK ASSESSMENT


• No task is completely without risk• Must develop tailored risk matrix, based upon acceptable risk, in order to identify what is considered sufficiently low

• Must define “acceptable risk”

1.3 ACCEPTABLE RISK


Acceptable Risk• What is it?

The threshold level below which risk will be tolerated

1.3 ACCEPTABLE RISK


Risk Class

Example Risk Classification(IEC61508-5)I.Unacceptable

II.Undesirable

III.Action Recommended(ALARP)

IV.Broadly Acceptable


1.3 ACCEPTABLE RISK


1.3 ACCEPTABLE RISK


1.3 ACCEPTABLE RISK


1.3 ACCEPTABLE RISK


Acceptable Risk


Acceptable Risk


Acceptable Risk

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