An HSE report in February (2022) concluded that "provided operating and maintenance instructions typically do not detail the need to replace all relevant components that are time-limited to less than the design life of the industrial UPS system" [1]. Their conclusion is that the majority of companies and data centres have inadequate maintenance schedules. The HSE report is a consequence of several dangerous failures of industrial UPS systems that resulted in serious fires and the release of toxic pollutants - incidents that would have been prevented by adequate maintenance schedules and timely UPS battery replacement.
The leading causes of sudden failures are the capacitors, batteries and switchgear (usually from heat damage). The HSE also explicitly mention cooling fans, RAM batteries and the power and control PCBs. The HSE report, therefore, warns all owners and designers of UPS equipment to ensure their maintenance practices are thorough, in accordance with the manufacturer's most current guidelines and fully compliant with the Health & Safety Acts that apply in their industries.
Other important components of a UPS system include the input and output transformers, rectifier, inverter, air filters, alarms, status indicators, meters, circuit breakers and the management system (for which firmware and software must be up to date). Circuit boards should be inspected at the component level - looking for scorching, swelling or leakages. Of equal importance are the cables, terminals, racks and cabinets - which must be monitored for corrosion, scorch marks, dust or grime. Cleaning is by no means the least of your maintenance priorities and the ventilation of the enclosing room is also important.
Many of these components involve high voltages and meticulous electrical testing, so not all tasks can be performed by an in-house IT team.
Planning a UPS maintenance schedule
Devising adequate and cost-effective maintenance plans is a job for specialists rather than end-operators: UPS maintenance practices learned on one system cannot simply be applied to another. Referring back to the manufacturer's published materials is always essential but even then - because of the combination of parts, size, total power demands and the environmental conditions - every UPS implementation may need its own maintenance plan.
There are significant risks associated with UPS battery replacement and other maintenance activities. Few operators have the training to handle high voltage equipment, which presents health and safety risks and legal ones too. Under no circumstances should untrained personnel undertake routines or interventions that could expose them to high voltages. It is wise to define the routine maintenance duties of your operators in writing and to keep records of each procedure carried out (which is H&S best practice). This is not to say that operators should have no maintenance responsibilities - they should, but primarily to monitor performance metrics and report concerns.
Record keeping is essential for a variety of reasons. The most obvious is to ensure that no procedure is overlooked. The second is to reveal long-term trends in the performance metrics that reveal the date when equipment should be replaced (allowing you to budget). The third is to provide evidence of correct procedures for the HSE and your insurance companies. The fourth is to provide documentation for training new employees in managing the system. Your outside UPS professionals also rely on these records and add to them on every visit.
UPS battery replacement
How you treat and maintain your batteries has a major influence on how long they last. Replacing a whole bank of batteries is no small investment so maximising their lifespan is common sense. Temperature control is important and so is maintaining the electrolyte and stability of the charging current (from the inverter or any other equipment you use). Nevertheless, most become unreliable after 3 to 5 years. Imagine what that means: with a poor maintenance regime, you could need complete UPS battery replacement after 2yrs but with an excellent one it could be 6yrs. Failing to protect your asset can double or treble your running costs.
The Lifespan of battery banks can be extended by early replacement of faulty batteries, and batteries themselves can sometimes be rescued by the replacement of faulty cells. A range of regular examinations and maintenance routines are essential in order to minimise your risks and long-term running costs.
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