Fire Extinguishers

A fire extinguisher is an active fire protection device used to extinguish or control small fires, often in emergency situations. It is not designed for use on an out-of-control fire, such as one which reaches the ceiling, endangers the user (i.e. no escape route), or otherwise requires the expertise of a fire department. Typically, a fire extinguisher consists of a handheld cylindrical pressure vessel containing an agent which can be discharged to extinguish a fire.


How to Use a Fire Extinguisher

Even though extinguishers come in a number of shapes and sizes, they all operate in a similar manner. Here's an easy acronym for fire extinguisher use:

P A S S - Pull, Aim, Squeeze, and Sweep


Pull the pin at the top of the extinguisher that keeps the handle from being accidentally pressed.

Aim the nozzle toward the base of the fire.

Stand approximately 8 feet away from the fire and squeeze the handle to discharge the extinguisher. If you release the handle, the discharge will stop.

Sweep the nozzle back and forth at the base of the fire. After the fire appears to be out, watch it carefully since it may re-ignite!

Types of fire extinguishers

There are various types of extinguishers, which are used for different types of fires; using the wrong type can worsen the fire hazard, so it is critical to match the extinguisher type to the situation.Fire extinguishers are often misused to hold automatically closing fire doors open. This misuse moves the extinguishers from its desired location and will allow any smoke or fire to pass rapidly through the door opening. In many countries it is an offense to do so.HistoryThe first automatic fire extinguisher of which there is any record was patented in England in 1723 by Ambrose Godfrey, a celebrated chemist. It consisted of a cask of fire-extinguishing liquid containing a pewter chamber of gunpowder. This was connected with a system of fuses which were ignited, exploding the gunpowder and scattering the solution.

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 litres) of pearl ash (potassium carbonate) solution contained within compressed air.The soda-acid extinguisher was invented 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.

Around 1912 Pyrene invented the carbon tetrachloride (CTC) extinguisher, which expelled the liquid from a brass or chrome container by a handpump.In the 1940s, Germany invented the liquid chlorobromomethane (CBM) for use in aircraft. It was more effective and slightly less toxic than carbon tetrachloride and was used until 1969. Methyl Bromide was discovered as an extinguishing agent in the 1920s and was used extensively in Europe. It is a low-pressure gas that works by inhibiting the chain reaction of the fire and is the most toxic of the vaporizing liquids, used until the 1960s. The vapor and combustion by-products of all vaporizing liquids were highly toxic, and could cause death in confined spaces.

Installation

Fire extinguishers are typically fitted in buildings at an easily-accessible location, such as against a wall in a high-traffic area. They are also often fitted to motor vehicles, watercraft, and aircraft - this is required by law in many jurisdictions, for identified classes of vehicles. Under NFPA 10 all commercial vehicles must carry at least one fire extinguisher.

Most countries in the world require regular fire extinguisher maintenance by a competent person to operate safely and effectively, as part of fire safety legislation. Lack of maintenance can lead to an extinguisher not discharging when required, or rupturing when pressurized. Deaths have occurred, even in recent times, from corroded extinguishers exploding.

This is the new labeling style with a diagonal red line drawn through the picture to indicate what type of fire this extinguisher is NOT suitable for. In this example, the fire extinguisher could be used on Ordinary Combustibles and Flammable Liquids fires, but not for Electrical Equipment fires.

Types of Fire Extinguishers

Dry Chemical extinguishers are usually rated for multiple purpose use. They contain an extinguishing agent and use a compressed, non-flammable gas as a propellant.

Halon extinguishers contain a gas that interrupts the chemical reaction that takes place when fuels burn. These types of extinguishers are often used to protect valuable electrical equipment since them leave no residue to clean up. Halon extinguishers have a limited range, usually 4 to 6 feet. The initial application of Halon should be made at the base of the fire, even after the flames have been extinguished.

Water: These extinguishers contain water and compressed gas and should only be used on Class A (ordinary combustibles) fires.

Carbon Dioxide (CO2) extinguishers are most effective on Class B and C (liquids and electrical) fires. Since the gas disperses quickly, these extinguishers are only effective from 3 to 8 feet. The carbon dioxide is stored as a compressed liquid in the extinguisher; as it expands, it cools the surrounding air. The cooling will often cause ice to form around the “horn” where the gas is expelled from the extinguisher. Since the fire could re-ignite, continue to apply the agent even after the fire appears to be out.

Fire safety

Fire safety is a component of building safety. It concerns safety measures to prevent fires or limit their effects.Fire-Fighting, techniques used to extinguish fires and limit the damage caused by them. Fire-fighting consists of removing one or more of the three elements essential to combustion—fuel, heat, and oxygen—or of interrupting the combustion chain reaction.

Most fire-fighting consists of applying water to the burning material, cooling it to the point at which combustion is no longer self-sustaining. Fires involving flammable liquids, certain chemicals, and combustible metals often require special extinguishing agents and techniques. With some fuels the use of water may actually be dangerous.

Examples of such lawful conduct include, but are not limited to, the following:-
- Not exceeding the maximum occupancy listing for any part of the building.
- Maintaining proper fire exits and proper signage of them (e.g., exit signs pointing to them that can function in a power failure)
- Placing and maintaining fire extinguishers and fire alarms in easily accessible places.
- Properly storing/using, that may be needed inside the building for storage or operational requirements (such as solvents in spray booths).
- Banning of flammable materials in certain areas of the facility.
- Routinely inspecting public buildings for violations, issuing Orders To Comply and, potentially, prosecuting or closing buildings that are not in compliance, until the violations are corrected or condemning it in extreme cases.
- Installing and maintaining fire alarm control panels for quick detection and warning of fire.
- Obtaining and maintaining a complete inventory of firestops.
- Ensuring that all spray fireproofing remains undamaged.
- Maintaining a high level of training and awareness of occupants and users of the building to avoid obvious mistakes, such as the propping open of fire doors.
- Conduct fire drills at regular intervals throughout the year.


Alarm Systems

Buildings may also be equipped with detection systems that will transmit an alarm. Some detectors are designed to respond to smoke, and others to heat. In many jurisdictions, detection systems are required in public buildings, apartment houses, and sometimes even in private homes.Two major types of smoke detectors are available. One is an ionization device that contains a small radioactive source for ionizing the air molecules between a pair of electrodes, permitting a very small current to flow between the pair. The second type of smoke detector uses a photoelectric cell. In some of these detectors, smoke that enters obscures a steady beam of light; in others, the smoke scatters a light ray from a diode so that the cell can detect it.


Fire code

The Fire code (also Fire prevention code or Fire safety code) is a model code adopted on a regional basis and enforced by fire prevention officers within municipal fire departments. It is a lawful set of rules prescribing minimum requirements to prevent fire and explosion hazards arising from storage, handling, or use of dangerous materials, or from other specific hazardous conditions.

A typical fire safety code includes administrative sections about the rule-making and enforcement process, and other substantive sections dealing with fire suppression equipment, particular hazards such as containers and transportation for combustible materials, and specific rules for hazardous occupancies, industrial processes, and exhibitions.

Each section may lay out the requirements for obtaining permits, and specific precautions required to remain in compliance with a permit. For example, a fireworks exhibition may require an application to be filed by a regionally licensed pyrotechnician, providing the information necessary for the issuing authority to determine whether the safety requirements can be met. Furthermore, once a permit is issued, the same authority (or another delegated authority) may inspect the site and monitor the safety during the exhibition, with the power to halt unapproved operations, or where unforeseen hazards arise.