Guide
Air compressor service intervals: hours, calendar and the legal bit
Updated
Two clocks run on a compressor house, and people mix them up constantly. One is the manufacturer's service schedule. The other is the statutory examination under your written scheme. Neither one sets the other.
Clock one: the manufacturer's schedule
Routine servicing intervals are set by the machine's manufacturer, normally in running hours, sometimes with a calendar backstop for machines that run little. The handbook is the authority for your model, and hours vary between makes, between oil types and between duty cycles. A machine that runs continuously will reach its major service several times in the period a lightly loaded machine takes to reach it once.
- Read hours, not months. Fit an hours meter reading into your planning, and set the calendar visit around it rather than the other way round.
- Oil type changes the interval. Mineral, semi-synthetic and full-synthetic lubricants carry different service lives, and using a longer-life oil is a legitimate way to stretch an interval if the manufacturer allows it.
- Ambient conditions shorten it. Dust, heat and poor ventilation load the coolers and the intake filter. A foundry compressor house is not a clean assembly hall.
- Air treatment runs on its own schedule. Filter elements, drains and desiccant charges are not tied to the compressor's hours.
Clock two: the statutory examination
Compressed air above 0.5 bar above atmospheric pressure is a relevant fluid, so the installation is a pressure system under the Pressure Systems Safety Regulations 2000 (HSE). Under those regulations a written scheme of examination must be in place and an examination undertaken before qualifying equipment is used, and thereafter the system must be examined in accordance with that scheme.
There is no statutory interval to quote. PSSR does not name a number of months or years for compressed air. The frequency comes from your written scheme, drawn up or certified by a competent person for your specific system. Anyone who tells you the law says every two years, or every four, is describing a scheme they have seen, not the regulations. See the written scheme guide.
How the two clocks work together in practice
- Put both on one plan. Manufacturer service dates by hours, examination dates by scheme, on the same calendar, so nothing is missed and visits can be combined where the provider can do both.
- Keep the records. PSSR includes duties on maintenance and the keeping of records (regulations 12 and 14), and a maintenance log is also a PUWER expectation for work equipment generally.
- Review the scheme when the plant changes. New receiver, re-piped ring main, changed duty: the competent person should confirm the scheme still fits.