May 6, 2022
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The HSE recently issued a safety alert regarding the maintenance of industrial uninterruptable power supply systems.

Industrial uninterruptable power supply systems are used in several areas including the manufacturing, IT, chemical, energy and offshore oil and gas production industries. They provide an alternative power supply when the normal power source (e.g. the mains electrical supply) fails.

There are several types of industrial uninterruptable power supply systems, which is used will depend on the particular circumstances. These are commonly used where fluctuations in the power supply could cause costly or hazardous situations e.g. to provide a period in which machinery or processes can be safely shut down, where a loss in power supply would cause waste and a loss of production or where restarting a process is long and complicated.

The HSE’s safety alert follows investigations into a number of dangerous occurrences that resulted from the failure of industrial uninterruptable power supply systems. Some of the incidents involved fires within the system, failure of components and an unplanned shutdown of a chemical processing plant which subsequently on start-up led to an unplanned release of toxic substances into the environment.

Insufficient maintenance instructions were found to be a common theme in all of these cases. As well as a failure to provide suitable information in the initial operating instructions, the HSE also found that end users had typically not been provided with the necessary revisions of information for maintenance, based on experience in use e.g. where components were found to have significantly shorter life expectancies that were initially predicted.

End users of these systems often had a false sense of the reliability of the systems due to a lack of information on the need to replace all relevant components that are time limited to less than the design life of the industrial UPS system (batteries, filter capacitors, cooling fans, internal RAM batteries, power cards and control cards).

Safety alert advises designers, manufacturers, importers and suppliers of this equipment to review and revise the maintenance information they provide and to take steps to ensure that, where practical, all affected end users are provided with all revisions of information to assure safe and reliable continued operation.

End users are maintenance contractors are also being advised to make sure they have access to the latest revision of information for maintenance from the original equipment manufacturer. They should use this information to update existing maintenance arrangements and to ensure that the installed industrial system is being maintained accordingly.

Full details of the safety alert can be found on the HSE’s website at: https://www.hse.gov.uk/safetybulletins/ups-systems-industrial-maintenance.htm