Pressurised System Safety

Pressurised systems include heating circuits, hot water systems, compressed air lines, and hydraulic pipework.
Sudden failure of a pressurised system causes scalding, blast injuries, and projectile impacts from fragments.
The Pressure Systems Safety Regulations 2000 require a written scheme of examination for most pressure systems.
Safety valves, pressure relief devices, and expansion vessels protect systems from dangerous overpressure.
Never tighten, loosen, or work on fittings while the system is pressurised; depressurise fully first.
Flexible hoses on pressurised systems deteriorate with age and can burst without warning.
Hot water and steam under pressure cause instant severe scalding burns on contact with skin.
Compressed air at even low pressures can penetrate skin and cause fatal air embolism.
Pressure gauges must be maintained, calibrated, and readable to confirm system operating conditions.
PUWER 1998 and the Pressure Systems Safety Regulations 2000 both apply to pressurised system work.

Explosive failure	Pressurised systems store enormous energy. Catastrophic failure launches fragments and superheated fluid across the area.
Scalding burns	Hot water and steam under pressure cause instant deep burns over large body areas, often requiring skin grafts.
Legal compliance	The Pressure Systems Safety Regulations 2000 require written schemes, examinations, and safe operating limits.

Do

Don't

Depressurise systems fully before working on any fittings, valves, or joints.
Check that safety valves and pressure relief devices are functional and not blocked.
Follow the written scheme of examination for all pressure system inspections.
Verify pressure gauges are reading correctly and within the safe operating range.
Replace flexible hoses at the intervals specified by the manufacturer.
Wear appropriate PPE including face shield and gloves when breaking pressurised joints.
Ensure expansion vessels are correctly charged before pressurising heating systems.
Label all pressurised systems with the maximum safe operating pressure.
Report any unusual noises, vibration, or leaks from pressurised pipework immediately.
Use competent persons to install, commission, and maintain pressurised systems.

DON'T work on fittings, joints, or valves while the system is pressurised.
DON'T block, bypass, or adjust safety valves and pressure relief devices.
DON'T exceed the maximum safe operating pressure marked on the system.
DON'T use compressed air to blow dust off clothing or skin.
DON'T ignore leaks from pressurised systems; they indicate developing failure.
DON'T use aged or damaged flexible hoses on pressurised systems.
DON'T assume a system is depressurised; verify with the pressure gauge first.
DON'T point pressurised hose ends at yourself or anyone else.
DON'T skip the written scheme examination intervals for pressure systems.
DON'T operate pressurised equipment without understanding the safe operating limits.

See also: Pressure Testing Safety | Mechanical Building Services Safety

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