An annual tag says somebody looked at the outside of the cylinder this year. Service is what happens on the inside — the six-year teardown, the twelve-year pressure test, the valve rebuild, and the honest conversation about when a unit is not worth keeping.
Fire & Safety Equipment III LLC has been servicing portable fire extinguishers since 1975. Our shop is in Platteville, Wisconsin, and our technicians are based across Wisconsin, Iowa and northern Illinois — 10 service vehicles covering businesses in all three states. This page explains the maintenance clocks that run underneath your annual tag, what we do at each one, and how to tell when replacing beats repairing.
Three Clocks, Not One
Most people think of extinguisher compliance as a single yearly event. It is actually three schedules running at once on the same cylinder, and they come due independently.
Every year
Inspection and tag
A qualified technician verifies condition, pressure, weight, and placement, then tags it. This is the visible one — the tag on the handle. Covered in detail on our inspection page.
Every six years
Internal maintenance
Stored-pressure dry chemical units get emptied, opened, and examined internally. The agent is checked or replaced, the valve is rebuilt with new O-rings and a new gasket, the siphon tube is inspected, and the unit is recharged, pressurized, and leak-tested.
Every twelve years
Hydrostatic test
The cylinder is emptied and pressurized with water well above its service pressure to prove the shell will still hold. Some cylinder types — including CO₂ and certain cartridge units — run on a five-year cycle instead.
Miss the six-year and the twelve-year and your extinguisher can carry a perfectly current annual tag while being out of compliance. That is the finding that surprises people, and it is the one we see most often when we pick up an account from another vendor.
What Happens on a Six-Year Maintenance
The unit comes apart. That is the whole point — there is no way to know the condition of a siphon tube, a valve stem, or the agent itself from the outside.
We discharge and capture the agent, remove the valve assembly, and inspect the interior of the shell for corrosion, pitting, or moisture. Dry chemical that has caked or absorbed humidity gets replaced rather than reused. The valve is rebuilt with new seals, the siphon tube is checked for cracks and blockage, and the gauge is verified. Then the unit is refilled to weight, pressurized with nitrogen, leak-tested, sealed with a new pin and tamper seal, and stamped with a new service collar.
Done right it takes real time, which is why some outfits quietly skip it and just re-tag. The service collar on the neck is what proves it happened — and it is one of the first things we look at on units we inherit.
Hydrostatic Testing, and Why It Is Not Optional
A pressurized cylinder that fails is not a fire problem. It is a shrapnel problem. Hydrostatic testing exists because steel that has been under pressure for a decade, banged into things, and stored in a humid basement does not stay the same steel it started as.
The test fills the cylinder with water and takes it well above its rated service pressure while measuring expansion. A shell that expands too much or does not return to shape fails, and a failed shell gets condemned — not repaired, not re-tagged, condemned.
We do this testing in our own shop in Platteville. Fire & Safety Equipment III holds U.S. DOT requalifier identification number G347, issued by PHMSA, which authorizes us to hydrostatically requalify DOT-4B low-pressure cylinders — the shells on most dry chemical extinguishers. Cylinders that pass get our RIN and a new date stamped into the shell and go back into service. Cylinders that fail get condemned and replaced, and we will show you why. Cylinder types outside that authorization are sent to a qualified requalifier and tracked the same way.
The dates you actually need to track
Annual inspection every year. Internal maintenance at six years for most stored-pressure dry chemical units. Hydrostatic test at twelve years for steel dry chemical shells, and five years for CO₂ and several cartridge-operated types. We track all of it per unit for every account we service, so it arrives as a scheduled visit instead of a violation.
When Replacing Beats Repairing
There is a point where a five-pound extinguisher costs more to test than to replace. We will tell you when you have reached it rather than billing you for the service and letting you find out later.
Small dry chemical units approaching a hydro date are usually the clearest case — the test, the recharge, and the labor add up past the price of a new unit that resets every clock. Larger units, wheeled units, clean agent extinguishers, and CO₂ cylinders are almost always worth servicing, because the replacement cost is real money.
We also stock refurbished units. A refurbished extinguisher is a used shell that has passed hydrostatic testing, been fully serviced, and been recertified — it carries the same compliance as new at a lower price, which matters when you are outfitting a whole building at once.
Getting the Right Extinguisher on the Wall
Service is not only about keeping what you have running. It is also about whether what you have is the right thing.
ABC dry chemical covers most general hazards and is what hangs in most buildings. It is also messy and mildly corrosive, which is why a server room, a control panel, or a room full of instruments is usually better served by a clean agent unit that leaves no residue. Kitchens need a Class K wet chemical unit next to the cooking line — an ABC is the wrong tool there and can make a grease fire worse. Shops with flammable liquids, welding areas, and mechanic bays each have their own answer.
We carry ABC, BC, Class K, clean agent, CO₂, water, and wheeled units, and we would rather put the right one on your wall than sell you another of what you already have. If your operation has changed — new equipment, new chemicals, a new process — that is worth a conversation at your next service visit.
Mobile Service, Wherever You Are
Most of this happens at your building. Our vehicles carry parts, seals, brackets, signage and a rotation of fully serviced, tested and tagged extinguishers, so a technician can inspect, re-tag and swap on site and leave your walls covered. Units that need a recharge, a hydrostatic test or a full teardown come off the wall and a tested unit goes up in their place. The swap stays — you are never non-compliant and there is nothing on loan to return. If you would rather keep a particular unit and have it back after service, just ask.
Units that have been discharged or lost pressure go through recharge in our shop. If your building also has a commercial kitchen, we handle the suppression system and the hood cleaning too — separate crews, one company.
The Standards That Define “Service”
Extinguisher service is one of the more heavily written-down trades there is. Nearly everything our technicians do to a unit — how often, in what order, with what documentation — is prescribed by NFPA 10 and backed by federal workplace law. Here is the framework, so that when a tag, a collar or a test date is mentioned on your invoice, you know which rule it is satisfying.
Inspection, maintenance and recharging
Chapter 7 is the service calendar. Owners inspect monthly. A trained person performs maintenance annually — a thorough examination of the mechanical parts, the agent and the expellant, with a new tag each time. Stored-pressure dry chemical units get an internal examination every six years; cartridge-operated dry chemical units get one every year. Maintenance also includes the conductivity test on CO₂ hose assemblies, replacement of tamper seals, and a check that the unit is the right type and rating for the hazard it is protecting.
Hydrostatic testing intervals
Chapter 8 sets the pressure-test schedule every extinguisher cylinder has to meet before it can stay in service: twelve years for most stored-pressure and cartridge-operated dry chemical units, and five years for carbon dioxide, pressurized water, wet chemical and foam units. It also lists the conditions that require an early test or outright condemnation — corrosion, dents, burn damage, a broken hanger weld, mismatched parts, or a repair to the shell. A cylinder past its test date cannot be refilled until it has been tested.
The employer’s side of the same schedule
OSHA’s rule mirrors NFPA 10 for workplaces: monthly visual inspection, an annual maintenance check with a record kept for a year, the six-year internal maintenance on stored-pressure dry chemical units, and hydrostatic testing at the intervals in its Table L-1 — the same twelve- and five-year numbers. It also requires alternate protection whenever a unit is out for service, and it prohibits carbon tetrachloride and chlorobromomethane extinguishers and inverting-type units outright.
Choosing the right extinguisher is also a code requirement
NFPA 10 does not just say “have an extinguisher.” Chapters 5 and 6 tell you which one and where. Hazards are classed as light (offices, classrooms, churches), ordinary (retail, light manufacturing, parking garages, most restaurant dining rooms) or extra (woodworking, vehicle repair, paint and flammable-liquid handling, commercial kitchens), and the minimum rating rises with the hazard. Light-hazard areas need at least a 2-A extinguisher within 75 feet of travel; ordinary hazard needs 2-A as well but with more units per floor area; extra hazard needs a 4-A. For flammable liquids the numbers are 5-B or 10-B for light hazard, 10-B or 20-B for ordinary, and 40-B or 80-B for extra hazard, with the smaller rating placed within 30 feet of the hazard and the larger within 50. Class K units go within 30 feet of cooking appliances, and Class D units within 75 feet of combustible-metal work. A ten-pound ABC on the wall of a body shop may be the wrong extinguisher even if it is perfectly maintained, and part of a real service visit is catching that.
Replacement is a code decision too
NFPA 10 lists extinguisher designs that must be removed from service regardless of condition: soda-acid, chemical foam, vaporizing-liquid, cartridge-operated water and loaded-stream units, copper or brass shells joined by soldering or rivets, CO₂ extinguishers with metal horns, solid-charge AFFF units, pressurized-water extinguishers built before 1971, any extinguisher that is not listed and labeled, and stored-pressure dry chemical extinguishers manufactured before October 1984. And any extinguisher whose parts are no longer available from the manufacturer, or that fails hydrostatic testing, is condemned rather than repaired. When we recommend replacing instead of testing, one of those provisions is usually the reason.
What Wisconsin, Iowa and Illinois require
Wisconsin adopts NFPA 1, the Fire Code, through Wis. Admin. Code ch. SPS 314 and applies it to every public building and place of employment; NFPA 1 requires portable extinguishers to be maintained per NFPA 10, and Wis. Stat. § 101.14(2) has the local fire department inspecting those buildings on a recurring schedule, typically twice a year. Iowa’s Iowa Admin. Code 481—Chapter 280 adopts the 2024 International Fire Code, and IFC Section 906 requires extinguishers to be selected, installed and maintained to NFPA 10. Illinois works through the Office of the State Fire Marshal’s Life Safety Code rules and locally adopted fire codes. And wherever there is an employer, 29 CFR 1910.157 applies on top. Service done to NFPA 10 by a trained technician, documented with a tag and, where applicable, a collar, meets every one of those requirements.
- NFPA 10, Standard for Portable Fire Extinguishers — National Fire Protection Association
- 29 CFR 1910.157, Portable fire extinguishers — Occupational Safety and Health Administration
- Wis. Admin. Code ch. SPS 314, Fire Prevention — Wisconsin Legislature
Since 1975
We started as one man with one truck. In 1985 we bought the old furniture building at 5675 Southwest Rd in Platteville and never left. Fifty years on we are 16 people and 10 vehicles working across Wisconsin, Iowa, and Illinois. We still have the shop, the bench, and the parts to keep older units in service when it makes sense. Read the full story.
Extinguisher Service Where You Are
Service and testing runs on a route, which keeps costs down for everybody on it. These are the markets we cover most often — pick your city for local details.
Iowa
Wisconsin
Questions We Get Asked
What is the difference between an inspection and service?
An inspection is the annual visual check and tag. Service is the work underneath it — the six-year internal maintenance where the unit is opened and rebuilt, and the twelve-year hydrostatic test that proves the cylinder still holds pressure. A current tag does not mean those are current.
How do I know when my extinguisher is due for a six-year or hydro test?
Look at the collar on the neck and the stamps on the shell. If you would rather not decode them, send us a photo or let us walk the building — we track those dates for every unit on every account we service, so nothing lapses quietly.
How often is hydrostatic testing required?
Every twelve years for most dry chemical extinguishers, and every five years for CO₂ and certain cartridge units. The test date is stamped on the cylinder, and we track it on your report so it never sneaks up on you.
Is it cheaper to service or replace an extinguisher?
For small dry chemical units coming up on a hydro date, replacing is usually cheaper and resets every clock. For larger units, wheeled units, clean agent, and CO₂, servicing is almost always the better value. We will tell you which side of that line you are on before we do the work.
What is a refurbished extinguisher?
A used shell that has passed hydrostatic testing, been fully serviced, and been recertified. It carries the same compliance as a new unit at a lower price, which helps when you are outfitting a whole building at once.
Do I get a loaner while mine are being tested?
Better: you get a swap. When a unit has to go to the shop, a tested, tagged unit of the same type goes on your wall and stays there, so you are never non-compliant and there is nothing to return. If you want a specific unit back after service, tell us and we will arrange it.
I have a server room. Should I use a regular ABC extinguisher?
Probably not. ABC dry chemical works but leaves a corrosive residue over everything, which on electronics can cost more than the fire would have. A clean agent unit discharges and leaves nothing behind. Same logic applies to control panels and instrument rooms.
What areas do you cover?
We run 10 service vehicles with technicians based across Wisconsin, Iowa and northern Illinois, and cover businesses in all three states. If you are not sure whether you are in range, call and ask — we will tell you straight.
Tell us what you have and where you are.
Extinguishers, a kitchen system, a hood, a booth — one visit, one invoice. We reply the same business day.
5675 Southwest Rd, Platteville, WI 53818 · Mon–Thu 8:00–4:30, Fri 8:00–2:00