Which rules apply
For a contractor, three sources set the schedule, and they agree on the shape of it:
OSHA construction
1926.150(c)(1)(viii): extinguishers inspected periodically and maintained to the NFPA standard. It also sets how many you need on site.
OSHA general industry
1910.157: the monthly visual check, annual maintenance, 6-year service and hydrostatic tests. It covers your shop and yard.
NFPA 10
The standard the service companies work to, and that fire marshals and insurers check against. Your state or city may adopt it with changes.
The monthly check
It's a look, not a service, and anyone shown how can do it in under a minute per extinguisher:
Monthly extinguisher check
- In its place, mounted or in its bracket, visible, and nothing stacked in front of it.
- Gauge in the green. Tap it; a needle that won't move may be stuck.
- Pin and tamper seal in place. A broken seal means it may have been discharged, even a little.
- Full. Lift it. A light one has leaked or been used.
- No damage: dents, rust, a cracked hose, a blocked nozzle, a melted label.
- Instructions facing out and readable. And the service tag shows an annual date in the last twelve months.
- Initial and date the tag. That's the record.
The annual maintenance
Once a year a trained service technician does a thorough maintenance check of each extinguisher: the mechanical parts, the agent, the pressure, the hose and nozzle. They attach a tag with the date and their name, and replace or recharge anything that fails.
Book it for the same month every year, for every extinguisher at once, including the ones in the vans. The service company comes to the yard; the vans have to be there that morning.
The 6-year service and the hydrostatic test
On top of the annual, some extinguishers are emptied and serviced inside, and every cylinder is pressure-tested on a long cycle. The interval depends on the type, printed on its label:
| Year | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Every extinguisher | Annual | Annual | Annual | Annual | Annual | Annual | Annual | Annual | Annual | Annual | Annual | Annual |
| Dry chemical (ABC, BC), stored pressure | 6-yr service | Hydro test | ||||||||||
| CO₂, water, foam (AFFF) | Hydro test | Hydro test |
Under all of it: a visual check every month, by someone on your crew.
- 6-year maintenance. Stored-pressure dry chemical extinguishers that need a 12-year hydrostatic test are emptied and serviced every six years. Recharging or testing restarts the six years (1910.157(e)(4)).
- Hydrostatic test. The cylinder is pressure-tested: every 5 years for CO₂ and water-based types, every 12 for most dry chemical (1910.157(f), Table L-1). The technician keeps a certification with the date, their signature and the extinguisher's serial number, which you keep until the next test (1910.157(f)(16)).
- Disposable ones. Extinguishers with non-refillable cylinders skip the 6-year service. NFPA 10 retires them 12 years after the date of manufacture.
How many, and where, on a jobsite
OSHA's construction rule sets the minimum, and your GC's site plan often asks for more:
- 1 One rated at least 2A for each 3,000 sq ft of building, with no more than 100 feet of travel to the nearest one (1926.150(c)(1)(i)).
- 2 At least one 2A on each floor, near the stairway on multi-storey buildings (1926.150(c)(1)(iv)).
- 3 One rated at least 10B within 50 feet of where more than 5 gallons of flammable or combustible liquid is being used (1926.150(c)(1)(vi)).
- 4 Kept from freezing where they're subject to it (1926.150(c)(1)(v)).
Add the ones your own work needs: one at every hot-work location, one in each vehicle, one at the fuel can and the generator. Those are the extinguishers that move, and the ones that miss their annual.
Keeping the records
The tag on the extinguisher is the record the fire marshal looks at. The office list is the one that tells you which tag is about to lapse. Keep both:
Per extinguisher
Your number, type and rating, size, manufacture date, and where it is.
Its services
The last annual, the last 6-year service and hydrostatic test, each with its date and the service company.
Where it is now
Which van, trailer or site. An extinguisher on a job you finished in spring won't be there when the technician comes.
Extinguishers are one line in the equipment inspection checklist, alongside the harnesses, lifts and ladders that have dates to keep.