When a fire extinguisher has been used, it must be recharged for only a few minutes to remain effective for the next fire. Most fire departments either have the equipment available on site to recharge extinguishers, or you may have to approach a professional fire equipment manufacturer to do the job. Whether you choose to do it yourself or have a professional come in, there are a few basic steps that must be taken.
Before Getting Started
Before recharging a fire extinguisher, you must be aware of what rating, or type, of extinguisher you have. There are class A, B, C and D extinguishers. Class A is a water or foam extinguisher that is usually in a silver cylinder and is used to extinguish materials like paper, plastics, wood or rubber.
Class B, C, D or combination ABC extinguishers are typically red. B and C are filled with Carbon Dioxide also known as CO2 or dry chemicals and can be used on electrical fires, oil, oil based paints, grease or gasoline fires. D extinguishers are used for industrial applications such as fires caused or fueled by flammable metals. They're usually filled with dry powders.
It is important to know what material needs to be refilled, as it would be detrimental if a cylinder was refilled with water when it should have been filled with dry powder chemicals. The time to find out is not when the flames are already present.
Discharging the Extinguisher
If the fire extinguisher has been used during fire suppression activities, even just once and not until it was emptied, it should be recharged anyway. The act of emptying an extinguisher is called "discharging" and may be done simply by squeezing the handle and holding it until no more water or dry powder chemical comes out anymore.
Any remaining liquid or dry powder must be emptied before a recharging, also called a refilling, occurs.
Cleaning and Checking
Cleaning and checking the various parts of the extinguisher is an important step before recharging. This includes cleaning the outside of the cylinder, also called the bottle, the hose and squeeze lever.
Make sure that the tubing, hose, nozzle, "O" ring, which seals the bottle shut, and stripping of the seal are all intact. If they show any sign of significant wear and tear, are weak and brittle or are clogged, now is the time to either replace the single parts or consider buying a whole new extinguisher.
Check the seal to make sure it is tight by submersing it in water. If you see bubbles escaping, there is a leak. Either retighten or replace the "O" ring.
Recharging/Refilling the Extinguisher
If completing this project yourself, you must have access to a pressurizing machine and a refill material of some sort, whether it is water or dry chemicals.
A product on the market called Fireade2000 is compatible with all ratings of extinguishers and is sold to the general public and to fire departments. This calls for their product, a bucket capable of holding 10 quarts, a funnel and water. The recharging may be done by anybody who follows the directions included in the packaging and uses an air compressor to finish it off.
Regardless of what product is being used, fill the extinguisher up to the predetermined level on the cylinder and use a pressuring machine to put the contents under pressure until the dial reads in the green zone, or about 100 to 175 psi, depending on the type of extinguisher you possess.
Finishing It Off
Once the material has been added into the cylinder and put under the proper pressure, all that is left to do is seal the extinguisher properly. Again, test for leaks by submersing it in water to see if bubbles escape, and readjust as necessary.
Finally, tag the extinguisher with the recharge date, the amount of pressure it was put under and the name of the person who completed the process.