We have all heard of water extinguishers, foam extinguishers, CO2 extinguishers, and dry chemical powder extinguishers. But there is also another type of extinguisher, which are known as the “Clean Agent” extinguisher.
What is a “Clean Agent” fire extinguisher?
It is a type of fire extinguisher that uses a volatile or gaseous fire extinguishant that is electrically nonconducting and that does not leave a residue upon evaporation.
What extinguishant is used in a “Clean Agent” fire extinguisher?
Clean agent fire extinguishers generally use HFC-236fa (1,1,1,3,3,3-Hexafluoropropane) extinguishant. It is colorless, odorless, non-corrosive, electrically non-conductive, and free of residue. Further, it is considered environmentally acceptable. It is stored as a liquid in the extinguisher, and when it is discharged, it discharges itself as a gas.
How do Hydrofluorocarbons (HFC) extinguish a fire?
Clean agent extinguishers act to extinguish a fire by smothering effect. They work in a similar manner to CO2 extinguishers by absorbing heat and reducing the concentration of oxygen. The halogenated agents extinguish the fire primarily via the removal of heat. They reduce the flame temperature to a temperature below that which is required for the maintenance of combustion along with inhibiting the chain reaction of combustion.
What classes of fire can a ‘Clean Agent’ fire extinguisher extinguish?
A clean Agent fire extinguisher can extinguisher:
Class A fire (i.e., Fire from ordinary solid combustible materials such as wood, paper, cloth, rubber, plastics, etc.)
Class B fire (i.e., Fire from flammable liquids, combustible liquids, aviation fuel, petroleum greases, oils, oil-based paints, solvents, alcohols, etc.)
Class C fire (i.e., Fire from flammable gases such as butane, propane, etc.))
A clean agent fire extinguisher can also be used on a fire that involves energized electrical equipment
What types of fire can a clean agent fire extinguisher not be used?
Clean agents should not be used on fires involving the following materials.
- Certain chemicals or mixtures of chemicals, such as cellulose nitrate and gunpowder, which are capable of rapid oxidation in the absence of air
- Reactive metals such as lithium, sodium, potassium, magnesium, titanium, zirconium, uranium, and plutonium
- Metal hydrides
- Chemicals capable of undergoing autothermal decomposition, such as certain organic peroxides, pyrophoric materials, and hydrazine
Where are clean agent extinguishers generally used?
In aircraft, airports, cell sites, computer rooms, server rooms, data centers, electrical vaults, switch gear rooms, file storage rooms, hotels & restaurants, indoor stadiums, museums, art galleries, libraries, operation theatres, train engines, wind turbines and much more…
What is the operating temperature of a clean agent extinguisher?
Clean agent extinguishers can operate in a wide range of temperatures from -40C to +55C.
What are the benefits of using a clean agent extinguisher?
Clean agent extinguishers can extinguish a wide range of fires very effectively. They also do not cause thermal shock damage to any electrical equipment. The extinguishant being electrically non-conductive and non-corrosive, it does not cause any damage to electronics and delicate mechanical devices. Further, the extinguishant is non-ozone depleting and has low toxicity too. Clean agents don’t leave a residue; thus, there is no clean-up required.
Clean agent extinguishers can be used in normally occupied spaces too.They can reach extinguishing concentration levels in just 10 seconds or even less. This makes them highly efficient in suppressing fire before significant damage can be done.
It does not contain chlorine or bromine and has zero ozone depletion potential like many fluoride-based gases.Thus, clean agent extinguishers are designed for the protection of any commercial and industrial facility that typically contains sensitive equipment, electronic data, or materials that could be damaged or destroyed by conventional fire extinguishing agents.
Thus, clean agent extinguishers are designed for the protection of any commercial and industrial facility that typically contains sensitive equipment, electronic data, or materials that could be damaged or destroyed by conventional fire extinguishing agents.
How are clean agent extinguishers identified?
A clean agent fire extinguisher will have an emerald green band and the letters in CLEAN AGENT written in white letters.
Article written by:
Mr. Hormuz Siodia, NEBOSH Approved Tutor, Green World Group – Dubai