Pressure Dewars

All Dewars operating at a pressure above 1.5 bar will be subject to the general requirements of PSSR (for safe operating limits, safe operation, maintenance).

In addition to the general requirements, Dewars which offer >250 bar litres will be subject to the full requirements of the regulations which also requires:

• a written scheme of examination (WSE)
• inspection and testing in accordance with the scheme
• records of testing to be maintained and;
• written details to be in place of action to be taken in the event of imminent danger

The following table indicates size of dewar and typical operating pressures which would warrant the dewar to be subject to the full requirements of the Pressure Systems and Safety Regulations (PSSR)

Dewar size (litres)	Max operating pressure (bar) = 250 bar litres
60	4.2
90	2.8
120	2.1
160	1.6
>160	will be subject to the full requirements of PSSR