Fire extinguishers typically consist of three main parts: a tank, valve assembly, and agent. Each type of fire can be put out by eliminating one or more elements that contribute to its ignition: heat, oxygen or fuel.
Carbon tetrachloride was widely used until 1969 as a gas used to extinguish hand-held fires with handheld fire extinguishers, as it prevented flames from reacting chemically with oxygen and producing smoke. Unfortunately, however, carbon tetrachloride can also be harmful to humans and can even kill in close spaces.
Water
Water fire extinguishers are designed with a small tank filled with tap water and pressurized by air, similar to an enormous squirt gun, to use on Class A (wood, paper and cloth) fires only.
Water can transform to steam when applied directly to a flame, dispersing heat away and depriving oxygen to suffocate it. Furthermore, spraying water on an incinerator helps cool combustible materials below their ignition temperature to stop them from spreading further.
APWs are very effective on Class A fires but are ineffective against Class B or C flames. Water cannot douse kitchen grease fires effectively either.
Therefore, specialized extinguishers designed specifically to extinguish Class K flames are found throughout campus kitchens containing chemicals that create a soapy foam blanket to adhere to cooking oils and block oxygen, effectively extinguishing them before spreading any further.
Be wary when using these messy extinguishers in such areas!
Foam
Foam extinguishers use liquid foam agents that contain cooling agents that separate oxygen from products to effectively defuse Class A fires, including hydrocarbons or polar solvents; they’re also effective against Class K involving cooking oils and fats.
These extinguishers typically contain Monoammonium Phosphate (commonly referred to as ABC dry chemical, tri-class or multipurpose), a white powder that acts like an ABC dry chemical in blocking off fuel sources and oxygen from reaching burning materials.
They may also include an Aqueous Film-Forming Foam agent known as an AFFF agent which can be discharged through an air aspirating or spraying branch pipe nozzle and was once housed as solid charge models but is now only pre-mixed versions are available.
These fire extinguishers are commonly utilized in warehouses, marine applications, flammable liquid storage facilities, and jet engine testing facilities to protect equipment and personnel. In the past, AFFF extinguishers contained perfluorooctane sulphonate (PFOS); however, this chemical has now been phased out in order to reduce global pollution levels.
Dry Chemical
Fire extinguishers that use free-flowing dry powder chemicals that smother fires are called dry chemical extinguishers and typically feature wetting agents to penetrate burning material more easily. They are typically used on Class B and C fires involving flammable liquids and are less effective than foam or carbon dioxide but also more cost-effective and nonconductive of electricity.
Dry chemical fire extinguishers use a pressurized spray of fine powder to blanket and smother fires, as well as break down any chain reactions causing metals to catch on fire. They are effective against both Class A and B flammable liquid fires as well as Class D metal-related fires such as magnesium, titanium, and sodium that have caught on fire.
Multipurpose dry chemical extinguishers often contain monoammonium phosphate and sodium bicarbonate-based powder that releases into the environment and corrodes electrical equipment as quickly as possible to ensure effective coverage against Class D metal-related fires involving magnesium titanium and sodium metals such as magnesium titanium and sodium fires if ignited during an attack by this extinguisher.
Carbon Dioxide
Carbon dioxide fire extinguishers deliver pressurized CO2 gas that effectively separates oxygen from flames, thus smothering them. They are especially suitable for Class B fires involving flammable liquids and gases as well as Class C electrical equipment fires.
These high-pressure vessels contain 5 or 10 pounds of liquid carbon dioxide that works by dislodging oxygen required to sustain combustion, effectively extinguishing any potential fire hazards found in mechanical rooms or labs.
MET-L-KYL carbon dioxide spray is a specialty variation made up of sodium bicarbonate and silica that creates a blanket or seal over fuel sources to stop oxygen from reaching them, extinguishing fires without risk of flashback and working well against aluminum fires as well.
Fire extinguishers are essential tools for fire safety, especially іn high rise building fire safety.
Conclusion
Understanding what does a fire extinguisher contain and how іt works can make a life-saving difference during an emergency. The various types of fire extinguishers, including water, foam, dry chemical, and carbon dioxide extinguishers, each serve specific purposes.
Knowing their ingredients and applications is crucial to effective fire suppression. Choosing the right extinguisher for the specific type of fire is critical, whether you’re addressing flames, separating oxygen, or cooling combustible materials.
Implementing comprehensive fire safety measures in high-rise buildings is vital to protecting lives and property.