11.3 Pressure systems

Question 1

With reference to the Pressure Systems Safety Regulations 2000, explain what is meant by a ‘pressure system’. 4 marks

Answer 1

(a) A ‘pressure system’ is a system comprising one or more pressure vessels of rigid construction, any associated pipe work and protective devices; the pipe work with its protective devices to which a transportable pressure receptacle is, or is intended to be connected; or a pipeline and its protective devices which contains or is liable to contain a relevant fluid, but does not include a transportable pressure receptacle. Examples of a ‘relevant fluid’ include: steam; a liquid which has a pressure 0.5 bar above atmospheric at the temperature of the liquid or at 17.5º C; a fluid or mixture of fluids which is at a pressure greater than 0.5 bar above atmospheric pressure when in equilibrium with its vapour at either the actual temperature of the liquid or at 17.5 degrees Celsius; or a gas dissolved under pressure in solvent contained in a porous substance at ambient temperature and which could be released from the solvent without the application of heat.

Question 2

The Pressure Equipment Regulations 1999 (PER) apply to

Answer 2

the design, manufacture and conformity assessment of pressure equipment, and assemblies of pressure equipment with a maximum allowable pressure greater than 0.5 bar.

Question 3

The PER do not apply to excluded pressure equipment and assemblies. Excluded equipment and assemblies are listed at Schedule 1 of the Regulations (Annex A of the Directive). The list is extensive and includes: 4

Answer 3

 Simple pressure vessels  Aerosol dispensers  Blast furnaces  Radiators and pipes in warm water heating systems.