Health and Safety Executive

Over-pressure protection:

HSE’s position

Stephen Murray

HSE inspector, process integrity team, Offshore Division

HSE’s job is to prevent people being killed, injured or made ill by work.

“Those who create the risk are best placed to manage it.”

Managing over-pressure protection

Health and Safety at Work etc Act 1974

• ‘the duty of every employer to ensure … the health, safety and welfare at work of all his employees’

• ‘the provision and maintenance of plant and systems of work that are … safe and without risks to health’

Managing over-pressure protection

Pressure relief devices are the last line of defence.

• PSV – inadequate sizing (Grangemouth, 1987)– recent survey 4% failed to lift

• Bursting disc – Gas releases through unrevealed

rupture

Managing over-pressure protection

gas

Heat Exch. HP Flare Drum

seawater

Managing over-pressure protection

PAH

gas

Heat Exch.LSH ESD

ESDV

HP Flare Drum

disc failure

no alarmtell-tail blocked

does not trip

seawater pumpsnot tight

shut-off

no level indication above LSH

observed pressure

4 barg

Multiple failuresliquid @+40m

Managing over-pressure protection

seawater

Relevant regulations:• ‘identify hazards and assess risks’

(Management of Health and Safety at Work Regs, 1999)

• ‘maintained in an efficient state, in efficient working order and in good repair’ (Provision and Use of Work Equipment Regs, 1998)

Managing over-pressure protection

Offshore regulations:• ‘prevent the uncontrolled release of flammable

substances’ (Prevention of Fire and Explosion, and Emergency Response Regs, 1995)

• ‘identification of safety critical elements and a verification scheme’ (Safety Case Regs, 2005)

Managing over-pressure protection

Onshore regulations:• ‘pressure system… shall be properly designed

and constructed… so as to prevent danger’ (Pressure Systems Safety Regs, 2000)

• ‘a written scheme for periodic examination’ including ‘all protective devices’ (PSSR, 2000)

Managing over-pressure protection

Summary, over-pressure systems:

• responsibility of ‘risk creator’;

• identify hazards & assess risks;

• appropriate design & construction;

• maintain in working order and good repair;

• examination or verification scheme to address condition.

Managing over-pressure protection

Health and Safety Executive

Managing over-pressure

protection: HSE’s view

Stephen Murray

HSE inspector, process integrity team, Offshore Division