Recharging is replacing or topping off the extinguishing agent in a fire extinguisher and includes pressurization with expellant gas for certain types. Whenever an extinguisher is discharged partially or fully, it needs to be recharged, which
means extinguishing agent of the correct type and amount needs to be added to the extinguisher. Quite often, this requires the replacement of the entire contents. The work needs to be done properly and in a safe manner so that the extinguisher
will operate as intended.
Recharging of extinguishers is to be performed by trained technicians that have the knowledge to safely and reliably perform the task. Recharging is performed in accordance with the minimum requirements of NFPA 10, Standard for Portable Fire
Extinguishers and the procedures outlined in the manufacturer’s service manuals. In order to recharge extinguishers safely, the technician needs the proper tools, recharging agents, lubricants, and manufacturer’s replacement parts or parts
listed for use in the extinguisher.
Periodic Recharge and Hydrostatic Test Intervals*
| Extinguisher Periodic |
Recharge Hydrostatic |
Test Recharge |
| Dry Chemical (stored pressure) |
6 |
12 |
| Halogenated Agent |
6 |
12 |
| Carbon Dioxide |
See Hydro Test |
5 |
| 2.5 Gallon Water |
See Hydro Test |
5 |
| 2.5 Gallon Water (loaded stream) |
1 |
5 |
| Wet Chemical |
See Hydro Test |
5 |
| Water Mist |
See Hydro Test |
5 |
| Foam (AFFF and FFFP) |
3 |
5 |
| Dry Chemical (cartridge and cylinder operated) |
N/A** |
12 |
Notes:
* Recharging is also required after any use (discharge) or if the need is identified during maintenance or monthly inspection.
** Dry chemical extinguishers of the cartridge or cylinder operated type are not recharged unless a discharge occurs.
|
Internal and External Condition of Cylinders [NFPA 10: 7.3.1]
Extinguishers are recharged according to the intervals outlined in the table. Prior to recharging, the hydrostatic test date is checked, the extinguisher is examined externally for dents and corrosion, and the internal surfaces are examined
for corrosion and contaminants. O-rings and valve stems are routinely replaced at the time of recharge.
Loaner Extinguisher [10: 7.1.3]
Extinguishers removed from service for recharging must be replaced with a “loaner” extinguisher that matches the type of hazard and has an equal or higher rating. Note: The same make and model will match the existing hanger.
Dry Chemical Agent [10: 7.8.3.4]
The dry chemical is permitted to be re-used, but only if a closed recovery system is employed to prevent contamination. Prior to re-use, check for proper type, contamination, and clumping or caking of the agent.
Topping Off [10: 7.8.3.3]
A partial discharge may only necessitate a “topping off”. For partially discharged extinguishers, the remaining dry chemical is checked for condition and can be re-used if no problems are found.
Halogenated Agent [10: 7.8.3.8]
Removal of any halogenated agent is required to be done using a closed recovery system. Once the cylinder is empty, it is examined internally with an inspection light (P/N 16CIL or 24CIL) and telescoping mirror (P/N IM) for corrosion and contamination.
The agent can be re-used if no corrosion or contamination is discovered.
Carbon Dioxide [10: 7.8.3.9]
Carbon dioxide used in extinguishers must comply with the following specifications:
- Oil content must not exceed 10 ppm by weight.
- Maximum water content of not more than 60 ppm by weight, at −52°F dew point.
2.5 Gallon Water Extinguishers [10: 7.8.3.10]
The amount of water in a 2.5 gallon water extinguisher is determined by the following methods:
Never overfill, as these extinguishers rely on the empty air space at the top to operate correctly.
Anti-Freeze for Water Extinguishers [10: 7.3.3.2.1]
Where there is a potential for freezing, an antifreeze additive is used. The only approved additive is called “loaded stream” (typically with a potassium acetate base). Loaded stream is most often shipped in a box with directions on how to
mix it with water. Re-use of loaded stream is permitted if an analysis is conducted according to manufacturer’s instructions.
Wet Chemical and Water Mist Extinguishers [10: 7.8.3.11]
Wet chemical and de-ionized water are not permitted to be re-used (contaminants can clog the tiny nozzle orifices). Therefore, any remaining agent needs to be discarded, prior to recharge. Only the agent on the extinguisher nameplate is permitted
to be used for recharging. Tap water should never be used for water mist, as it will not meet the non-conductivity requirement [10: 4.1.4.1]. Always use the de-ionized water intended for use in water mist extinguishers (check the extinguisher
label).
Foam Extinguishing Agent [10: 7.8.2.3]
Today’s foam extinguishers contain a premixed solution of foam and water. These extinguishers are field charged at the time of initial installation and then recharged, three years from the date of installation. The next time they are recharged
is at the five-year hydrostatic test interval. Only foam recommended by the manufacturer is used for initial charge and recharging.
Cartridge and Cylinder Operated Extinguishers [10: 7.3.3.3]
The dry chemical in cartridge or cylinder operated extinguishers is examined annually by opening the top of the unpressurized container and checking the agent condition. Although these extinguishers are internally examined annually, the agent
is not removed, only examined and probed.
Leak Test [10: 7.8.1.3.4]
Once an extinguisher is recharged and pressurized (stored pressure and carbon dioxide), a leak test is required to be performed prior to the extinguisher being returned to service. Squirt’n Bubbles Leak Detector (P/N LD1) is typically used
to check for leaks. The applicators on the head of the plastic bottle have small bores that are specifically designed for dispensing tiny amounts of the leak detection liquid. Once dispensed, if a bubble is formed, you have a leaker!
Recharge Records [10: 7.8.4.8]
After completing the recharging of an extinguisher, a Service Tag is attached with the following information:
Recharged extinguishers are also required to have Verification of Service Collars installed (except carbon dioxide and halogenated agent extinguishers that are recharged without valve removal and cartridge and cylinder operated extinguishers).
Tamper Seals need to be replaced after recharging.
In order for an extinguisher to be fully effective, its extinguishing agent needs to be replaced or replenished when a discharge occurs. Knowing the code requirements for recharging extinguishers will help you ensure your customers have extinguishers
that are code compliant, fully charged, and ready for use in the event of a fire emergency.
Mark Conroy is an engineer in our Boston office.