I need to have the fire extinguishers in the office serviced. At the moment, we have the powder type. Someone suggested that it may be good to change to CO2 as the powder extinguisher leaves behind a messy residue. Price factor aside (CO2 is more expensive than powder form), what are the advantages of using one over the other? This is what I found out :
1. There are different classes of fire.
- Class A fires involve ordinary combustible materials such as paper, wood, cardboard, and most plastics.
- Class B fires involve flammable or combustible liquids such as gasoline, kerosene, grease and oil.
- Class C fires involve electrical equipment, such as appliances, wiring, circuit breakers and outlets. Never use water to extinguish class C fires – the risk of electrical shock is far too great!
- Class D fires involve combustible metals, such as magnesium, titanium, potassium, sodium etc found in chemical labs.
Source : http://www.fire-extinguisher101.com
2. Powder (ammonium phosphate) is more versatile as it is suitable for Class A, B and C fires.
3. CO2 is more suitable for use in computer rooms and kitchens as fires at these places would involve flammable liquids (grease, oil, kerosene) and extensive electrical equipment i.e. Class B and C (D too?) fires.
So which fire extinguisher you choose is highly dependent on where you are going to use it. If you have no fire extinguisher in the house and a fire has started up on your stove, DO NOT DOUSE IT WITH WATER or you’ll be in trouble. Have a look at this video.
This site offers a good write-up on the various types of fire-extinguishers.