The PSSR regulations apply to owners / users of pressure systems containing a relevant fluid including steam, gases under pressure and any fluid kept artificially under pressure which when released to atmosphere becomes a gas.
There is a legal requirement for Thorough Examination of pressure vessels that contain steam, compressed air and refrigerants. Any pressure vessel containing compressed gas over 250 bar / litres capacity requires inspection. Pressure systems require to be inspected in accordance with a Written Scheme of Examination.
To establish whether you require a pressure vessel inspection, multiply the vessel operating pressure (in bar) by the vessel capacity (in Litres) i.e. 10 bar x 50 Litres = 500 bar / litres capacity and therefore requires inspection as it is above the 250 bar / litre threshold.
Owner / users of refrigeration plant containing pressure vessels, with compressor power over 25 kilowatts also require a written scheme of examination and inspection.