fire extinguisher
- The first fire extinguisher record was patented in England in 1723 by Ambrose Godfrey.It consisted of gunpowder.
- The modern fire extinguisher was invented by British Captain George William Manby in 1818; it consisted of a copper vessel of 3 gallons (13.6 liters) of pearl ash (potassium carbonate) solution contained within compressed air.
- A soda-acid extinguisher was patented in the U.S. in 1881 by Almon M. Granger. His extinguisher used the reaction between sodium bicarbonate solution and sulfuric acid to expel pressurized water onto a fire.
The UK recognizes five fire classes:
- Class A fires involve organic solids such as paper and wood.
- Class B fires involve flammable or combustible liquids, including petrol, grease, and oil.
- Class C fires involve flammable gases.
- Class D fires involve combustible metals.
- Class F fires involve cooking fat and oil.
- Monoammonium phosphate, also known as "tri-class", "multipurpose" or "ABC" dry chemical, used on class A, B, and C fires. It receives its class A rating from the agent's ability to melt and flow at 177 °C (350 °F) to smother the fire. More corrosive than other dry chemical agents. Pale yellow in color.
- Sodium bicarbonate, "regular" or "ordinary" used on class B and C fires.
- Potassium bicarbonate (aka Purple-K), used on class B and C fires. About two times as effective on class B fires as sodium bicarbonate, it is the preferred dry chemical agent of the oil and gas industry. Violet in color.
- Potassium bicarbonate & Urea Complex (aka Monnex/Powerex), used on Class B and C fires. More effective than all other powders due to its ability to decrepitate (where the powder breaks up into smaller particles) in the flame zone creating a larger surface area for free radical inhibition. Grey in color.
- Potassium Chloride, or Super-K dry chemical was developed in an effort to create a high efficiency, protein-foam compatible dry chemical. Developed in the 60s, prior to Purple-K, it was never as popular as other agents since, being a salt, it was quite corrosive. For B and C fires, white in color.
- Foam-Compatible, which is a sodium bicarbonate (BC) based dry chemical, was developed for use with protein foams for fighting class B fires. Most dry chemicals contain metal stearates to waterproof them, but these will tend to destroy the foam blanket created by protein (animal) based foams. Foam compatible type uses silicone as a waterproofing agent, which does not harm foam. Effectiveness is identical to regular dry chemical, and it is light green in color.
- MET-L-KYL / PYROKYL is a special variation of sodium bicarbonate for fighting pyrophoric liquid fires (ignite on contact with air). In addition to sodium bicarbonate, it also contains silica gel particles. The sodium bicarbonate interrupts the chain reaction of the fuel and the silica soaks up any unburned fuel, preventing contact with air. It is effective on other class B fuels as well. Blue/Red in color.
கருத்துகள்
கருத்துரையிடுக