The Health and Safety Executive (HSE) has recently released guidance for employers who use pressure systems in their workplace, as organisations start to open up again following the easing of lockdown measures in the UK.
It warns that if pressure systems have not been used for an extended period of time, as is likely the case during the coronavirus (COVID-19) pandemic, then they may become unsafe.
The HSE reminds organisations to check whether pressure systems forming part of machinery have exceeded their examination period, advising that you should ensure you have the agreement of a competent advisor before restarting the machine.
Guidance is also given around safety issues from contamination of fluids and/or gases generated, which may cause unexpected behaviour of the pressure elements of machinery leading to unintended outcomes, such as:
- water ingress
- air ingress
- internal structural corrosion
- bypass of safety devices
Restarting a pressure system safely
The HSE recommends that organisations should view the start-up of all pressure systems forming part of machinery as a functional pressure test, and that they take safety precautions as detailed in the guidance note on safety requirements for safety testing.
It gives a number of examples of how starting up a pressure system from cold could significantly impact upon the mechanical behaviour of the vessels, pipework and moving parts.
- steam systems should be gradually warmed through to prevent cracking of steel or cast iron components
- pressure relief valves contain mechanical spring mechanisms. There is potential that these may have seized or fatigued as a result of a constant level of compression over a period of time. We recommend that you closely inspect and test safety devices like these. If you have any concerns, replace them. (ie a new one that has relevant certificates)
- hydraulic fluids will be more viscous when cold. Often, parts appear to move more sluggishly and there can be a time delay in response to operating controls
- where hydraulic systems have been left switched on, continuous recirculation can result in significant increase in temperature of the fluid. Unintended release or hose failure would result in hot oil being sprayed out
The above information has been drawn from the HSE website page “Restarting workplace pressure systems safely during the coronavirus outbreak”. View it here.