Types of Portable Fire extinguishers:
- Spray Foam (Cream) type extinguishers: Here a chemical foam is made to form over the fire so that oxygen supply is cut off and fire dies down.
- Dry Chemical Powder type extinguisher: Here the fire is controlled by the inhibiting action of the dry chemical powder which breaks the chain reaction.
Fire Detection Systems:
Detection systems are based on smoke, heat, flame, gas leakage, combustion, water flow.
Conduction/Convection Heat detection: Housing of detector has a fusible element that melts at a specified temperature causing electrical contact to activate a fire alarm.
Smoke detector: These are used to detect fires in the incipient stages.
Heat detectors: They respond to high temperatures caused by fire.
Flame detector: Detects light from flames where rapid development of flame occurs.
Electromagnetic detectors: They employ photocells sensitive to infrared and ultraviolet light emitted by the fire.
Water flow detector: It indicates because the other detector types (smoke, flame or heat) is activated and starts the water sprinkler system.
Tips on Kitchen Fire Safety
Extra care should be taken when working in the kitchen in order to avoid the onset of a fire. Here are some safety tips:
Wear appropriate clothing, not long, flowing sleeves or open, loose-fitting shirts that can come in contact with hot burners.
Wear your long hair up and do not leave any strands hanging.
Never take your eyes off hot oil because it can ignite in an instant. If it catches fire, immediately place a cover on the pan.
Always unplug electrical cords from all ancillary appliances. A plug can ignite even though the equipment is turned off. Any power surge or unforeseen problem with electricity can cause a fire.
Do not use electrical appliances near water and keep cords away from all heat sources.
Turn pot handles inward on the hot stove so as to avoid bumping into them accidentally and spilling their contents.
Do not place potholders, boxes, towels, cutting boards, or plastic utensils and containers near cooking areas.
Keep the kitchen work area clean, free from grease and burnt food.
Keep a box of baking soda on the kitchen counter while cooking as it can quickly put out a small fire at its onset.
Make sure all appliances are in good working condition. At the first sign of a problem, have it fixed or get rid of it.
Fire Extinguishers:
Fire extinguishers contain different chemicals, depending on the application. Handheld extinguishers, which are commonly sold at hardware stores for use in the kitchen or garage, are pressurized with nitrogen or carbon dioxide (CO2) to propel a stream of fire-squelching agent to the fire. The active material may be a powder such as potassium bicarbonate (KHCO3), liquid water, an evaporating fluorocarbon or the propelling agent itself. The most effective and common fluorocarbon used until recently for this application had been bromochlorodifluoromethane (CF2ClBr), referred to as halon 1211. By international agreement, however, production of all types of halons ceased in 1994 because the bromine and chlorine atoms in the chemical were found to migrate over time to the stratosphere, where they react to deplete ozone in a very efficient catalytic cycle.
Many fire extinguishing systems are built into the building or other structure being protected. Water sprinklers are by far the most common type of fixed system because they are inexpensive, highly reliable and safe for people. But water damage cannot always be tolerated (say, in a computer room or electrical fire); it is sometimes ineffective (a fuel storage system); and it is impractical where weight and space are limited (in an airplane). In these situations, fire extinguishers use different materials–ones that flood a protected compartment with a fire-fighting gas. CO2 works well, but is fatal at the concentrations necessary to extinguish a fire, and so cannot be used where people will be present. Bromotrifluoromethane (CF3Br, or halon 1301) is a close cousin to halon 1211, but has a much lower boiling point and toxic level–properties that have made halon 1301 the firefighting chemical of choice for applications where sprinklers cannot be used. Manufacturers have introduced new families of chemicals containing no chlorine or bromine, called hydrofluorocarbons (HFCs),that have physical properties similar to the halons and no ozone depletion potential. But lacking Br or Cl atoms, the HFCs cannot disrupt the combustion reaction to the same degree. HFCs extinguish fires in a manner similar to CO2 or N2–by absorbing heat and reducing the concentration of oxygen. Even so, several different companies are marketing such HFCs as CHF3, C2HF5, and C3HF7 for a variety of applications.
Most often, simple fire extinguishers use sodium carbonate and dilute sulfuric acid to produce carbon dioxide, that extinguishes fire. small pouch carries the acid within a matrix of sodium carbonate. The pouch prevents the acid to come in contact with sodium carbonate outside. When the bottle is shaken, the two chemicals come in contact with each other, liberating carbon dioxide and water droplets that extinguishers.
Another type of fire extinguisher contains compressed Carbon Tetrachloride in it. When the nozzle is pushed, an aerosol of carbon tetrachloride is liberated that suppresses and extinguishes fire.
This type has a major advantage that it can extinguish fires of oils, electric circuits, etc.
Other forms of fire extinguishers use forced water to extinguish fire.
Types of extinguishers:
Multi-Purpose Dry Chemical (A, B, C)
A dry chemical agent called mono ammonium phosphate. The chemical is non-conductive and can be mildly corrosive if moisture is present. In order to avoid corrosion, it is necessary to scrub and thoroughly cleanup the contacted area once the fire is out. A dry chemical fire extinguisher is usually used in schools, general offices, hospitals, homes.
Regular Dry Chemical (B, C)
A dry chemical agent called sodium bicarbonate. It is non-toxic, non-conductive and non-corrosive. It is easy to cleanup, requiring only vacuuming, sweeping or flushing with water. Extinguishers with sodium bicarbonate are usually used in residential kitchens, laboratories, garages.
Carbon Dioxide (B, C)
Carbon dioxide removes oxygen to stop a fire but has limited range. It is environmentally friendly and leaves no residue, so cleanup is unnecessary. Extinguishers with carbon dioxide are usually used in contamination-sensitive places such as computer rooms, labs, food storage areas, processing plants, etc.
Halotron (A, B, C)
A vaporizing liquid that is ozone friendly and leaves no residue. Because it requires no cleanup, fire extinguishers with halotron are ideal for computer rooms, telecommunication areas, theaters, etc.
Foam (A, B)
Foam floats on flammable liquids to tame the fire and helps prevent reflashes. To cleanup the affected area, it must be washed away and left to evaporate. Fire extinguishers with foam are usually used in garages, homes, vehicles, workshops.
Purple K Dry Chemical (B, C)
A dry chemical called potassium bicarbonate. It is non-conductive and non-corrosive. Clean up requires vacuuming, sweeping or flushing with water. Extinguishers with potassium bicarbonate are usually used in military facilities, oil companies, vehicles, etc.
Water (A)
The most common agent is water; however, it cannot be used for class B or C fires because it is conductive. Water-based fire extinguishers are usually used in stockrooms, schools, offices, etc.
Wet Chemical fire extinguishers (F)
The potassium acetate based agent discharges as a fine mist which forms a soapy foam that suppresses any vapors and steam or the risk of fire reflash as it extinguishes the fire. Class K fire extinguishers can usually be found in commercial cooking areas such as restaurants and cafeterias.