Pressure Equipment

November 2022 - information on current situation re contract provider.


The Pressure Systems Safety Regulations 2000 (PSSR) require certain specified actions to be carried out by anyone responsible for, or operating, a pressure system (see university Guidance: A Code of Practice for Pressure Equipment in the University of Cambridge).

This code of practice describes the management of equipment and systems operating above atmospheric pressure in the University. It complements the code of practice giving advice on the use of compressed gases and cryogens.

Pressure systems are defined as belonging to one of the following three arrangements:

  • A pressure vessel of rigid construction, associated pipework and protective devices, or
  • Pipework , protective devices and a transportable pressure vessel, or
  • Pipelines

Transportable pressure vessels, ie: gas cylinders, are not of themselves pressure systems, but become so when they are hooked up to other apparatus. They do, however, have to meet safety standards and they are subject to a statutary scheme of examination by the owners.

To qualify as a 'pressure system' under the Regulations, the equipment must be above the 250 bar litre threshold* and must contain either:

  • steam at any pressure, or
  • a gas or mixture of gases at a pressure of greater than 0.5 bar (1.5 bar absolute), or
  • a liquid with a vapour pressure greater than 0.5 bar (1.5 bar absolute), either at its actual temperature or at 17.5°C, or
  • a gas dissolved under pressure in a solvent contained on a porous substance which could be released without application of heat.

University pressure systems are likely to fall into one of the following broad categories:

  • Above the 250 bar litre threshold* (gas or cryogen systems), or containing steam: entered on the Insurance register and subject to Written Scheme of Examination.
  • Below the 250 bar litre threshold* (gas or cryogen systems): not named individually on the Insurance register, not subject to a Written Scheme of Examination.
  • Not belonging to the University, and therefore the responsibility of another employer ie: rented gas cylinders belonging to the supplier eg BOC etc.

* 'Bar litre' is the pressure in bars x volume in litres ie; 0.5 bar x 300 litres is only 150 bar litres and is below the threshold, whilst 0.5 bar x 600 litres is 300 bar litres and above the threshold.