can fire extinguishers be refilled?
all can be refilled, but some are easier than others. CO2 extinguishers have to go back to the manufacturer due the high pressures involved.
All other extinguishers are field refillable. I'll deal with water/foam as they are the simplest.
There are two types Stored Pressure and Cartridge. It is easy to tell the two apart. Stored Pressure have a pressure gauge on the headset, and cartridge don't.
With the stored pressure, you have to make sure there is no residual pressure, (by squeezing the handles), then take the headset off, do the service checks on the extinguisher and head / hose, then refill with water and additive if required. The replace all the o rings and refit the head cap. THEN you have to repressurise the extinguisher until the gauge shows mid scale. The weigh it and return to service. The stored pressure extinguisher is always under pressure and the pressure is held in by a valve in the headset.
Cartridge are much easier to deal with. The extinguisher isn't normally under pressure. When it is operated, the handles are squeezed and this pierces a CO2 cartridge inside the extinguisher. This pressurises the extinguisher and forces water out of the hose. This is a non reversable process. Great care needs to be taken to ensure that the extinguisher is not under pressure when removing the head set, never stand over it just in case (durr). When used, simply dismantle the head set, carry out the service checks again (o rings etc), refill with water and additive if necessary, fit a new cartridge and re-assemble.
The above are a vast over simplification of what is quite a long procedure in terms of items covered if not time. There are various checks and tests that have to be carried out during re-assembly and return to use.
hope that helps.
p.s. 10 year discharge test for CO2, 5 year for water and foam, 5 years usually for most powder depending on type. Usually as cheap to supply new than recharge stored pressure and **** about by the time you take labour into account. All extinguishers require a minimum of an annual service / inspection.
:rolly:
