Fire extinguishers · BS 5306-3
How often should a fire extinguisher be serviced?
A monthly check, a basic service every year, an extended service every 5 years and a CO2 overhaul every 10: who does each one and what to record.
The short answer
Portable fire extinguishers are looked after at four different levels. Each has its own person, its own interval and its own record:
| Check | Who | How often |
|---|---|---|
| Look-over by eye | The Responsible Person | Every month |
| Basic service | A competent person | At least once a year |
| Extended service | A competent person | Every 5 years, for water, foam, wet chemical and powder extinguishers |
| Overhaul with a hydraulic pressure test | A competent person | Every 10 years, for CO2 extinguishers |
These are the intervals in BS 5306-3. Read the current edition of the standard for the full wording, and follow the extinguisher maker's own instructions where they ask for more.
The monthly look-over
The Responsible Person, usually someone on site, checks each extinguisher by eye every month. The point is simple: is it there, is it where it should be, and does it look ready to use. A missing, damaged or obviously used extinguisher is dealt with straight away, not left for the next service.
It is worth writing this down. A log with twelve monthly entries is easy for an inspector to trust; a blank one is not.
The basic service, once a year
A competent person services every extinguisher at least once a year. The basic service is where an engineer checks the unit itself, including its weight. The mass check tolerance is plus or minus 5% of the charge, so an extinguisher that has lost more than that has lost some of its contents and does not pass.
Whatever the engineer finds, the visit should leave a record: which extinguisher, when, what was done, what was found and when it is next due.
The extended service, every 5 years
Every 5 years a water, foam, wet chemical or powder extinguisher gets an extended service, which goes further than the yearly basic one. Keep the date the extinguisher was last given an extended service, because that is what the next one counts from.
A simple way to track it: if the last extended service was in March 2024, the next is due in March 2029. The free service due date calculator works the next basic, extended and CO2 overhaul dates out from the date of the last one.
CO2 extinguishers are different
CO2 extinguishers are not given the 5 year extended service. They are overhauled every 10 years, with a hydraulic pressure test. They still get the monthly look-over and the yearly basic service in between.
What happens to one that fails
An extinguisher that fails its service should not go back on the wall. It is taken out of service and replaced, and the record should show what happened to it. That is one more reason to keep a proper register: the engineer can see at a glance which unit was replaced, when, and what the replacement is.
Common questions
Who can service a fire extinguisher?
A competent person: someone with the training, knowledge and experience to do the work, who keeps that up to date. The Responsible Person can do the monthly look-over.
How often does a CO2 extinguisher need servicing?
CO2 extinguishers have the monthly look-over and a basic service every year, and are overhauled every 10 years with a hydraulic pressure test. They do not have the 5 year extended service.
How much weight can an extinguisher lose before it fails?
The mass check tolerance is plus or minus 5% of the charge.
What counts as a monthly check?
The Responsible Person looks over each extinguisher by eye every month to make sure it is in place, undamaged and ready to use.
This guide is general information for UK fire & security companies, not legal or engineering advice. Always work to the current edition of the relevant standard and your own competent-person judgement.
See this on a real certificateKerova builds the register, readings and verdict into the certificate itself.
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