Fire extinguisher

ABC type fire extinguisher.

A fire extinguisher is a device used to put out fires. It consists of a metal container (steel cylinder) containing a pressurized fire extinguishing agent, so that when a valve is opened the agent comes out through a nozzle (sometimes located at the end of a hose) that must be directed to the base of the fire. They usually have a device to prevent accidental activation, which must be disabled before using the device.

More specifically, an extinguisher could be defined as a self-contained device, designed as a cylinder, which can be moved by a single person and which, using a drive mechanism under gas pressure or mechanical pressure, releases an extinguishing agent to the base of the fire in order to extinguish it.

There are many sizes and types, from the very small ones, which are usually carried in cars, to the large ones that go on a cart with wheels. The content varies from 1 to 250 kilograms of extinguishing agent.

History of fire extinguisher

The fire extinguisher was an invention of William George Manby, a captain who came up with the idea of creating an instrument that would extinguish fire more effectively by observing the inability of a group of Edinburgh firefighters to reach the upper floors of a burning building.

The first fire extinguisher was a device with four cylinders, three with water and one with compressed air, which served to pressurize the liquid out. It was patented in the United Kingdom in 1839. This device was modified in 1905 when water was replaced by sodium bicarbonate.

The first authentic portable fire extinguishers appeared at the end of the first decade of the 19th century; they contained glass bottles with acid that, when broken, discharged acid with a soda solution, generating a mixture with enough gas pressure to expel the solution. Water fire extinguishers, activated by cartridges (type of inversion), were introduced in the late 1920s. In 1918, an alkaline metal antifreeze solution called “charged current” was developed for the use of cartridge-activated fire extinguishers.

designfeu fire extinguisher
fire extinguisher

In 1959 water pressure accumulator fire extinguishers appeared, which gradually replaced the cartridge models within 10 years. In 1969, the manufacture of all reverse fire extinguishers was discontinued in the United States, and they are no longer certified or approved by test laboratories. The first foam fire extinguisher appeared in 1917 and its appearance and operation are very similar to acid and soda fire extinguishers. Their use was gradually extended over the years until powder extinguishers became widely accepted in the 1950s.

Classification by extinguishing agent

Depending on the extinguishing agent, you can distinguish between:

  • Water-based fire extinguishers charged with water or a foaming agent, AR-AFFF foam. Highly effective for their ability to enhance the wetting power of water, there are biologically active that encapsulate the gases and vapors generated by the fire break the molecules of hydrocarbons, inhibiting the reignition (flash back), do not pollute the environment, or harm people, except that, as water is conductive of electricity, can be very dangerous in fires of electrical origin.
  • Universal powder extinguishers; suitable for ABC fires
  • Dry chemical powder fire extinguishers (multifunction: fighting class BC fires)
  • CO2 fire extinguishers (also known as Carbon Snow or Carbon Anhydrous), are the most common and the best.
  • Metal fire extinguishers: (only valid for combustible metals, such as sodium, potassium, magnesium, titanium, etc)
  • Halon fire extinguishers (halogenated hydrocarbon, since 2010 its use is prohibited worldwide because it affects the ozone layer).
  • Instantaneous (formerly explosion extinguisher) is a fire rescue tool for professional use, which consists of an elastomer container, which contains flame retardant, and houses inside it a pyrotechnic element attached to a quick wick, which on contact with the fire, breaks the container and creates an oxygen-depleted bubble that extinguishes the fire, while cooling the area within a radius of about five meters.

Sorting by size:

Due to their size, fire extinguishers are divided into portable and mobile. Portable fire extinguishers would be those that weigh up to 20 kg in total, considering, in turn, between the same manual portable extinguishers, up to 20 kg and portable fire extinguishers dorsal up to 30 kg.

When a fire extinguisher weighs more than 90 kg it is considered mobile and must be on wheels to be moved.

This does not preclude the existence of fire extinguishers that are placed on wheels and therefore weigh less than 30 kg when they are moved. In fact, to facilitate handling, 50 kg fire extinguishers are usually installed on wheels.

The division has to do with the maximum allowed to be used in one way or another, i.e. a fire extinguisher weighing more than 20 kg must have a dorsal support.

The problem with fire extinguishers (except for the very large ones) is that the agent is quickly exhausted, so they must be used to their full advantage. Its time in continuous discharge is 18 to 20 seconds.

Likewise, they are distinguished by the fires they are capable of extinguishing: of electrical origin, originated by liquid fuels or originated by solid fuels, which depends on the extinguishing agent they contain. The possibilities that they have must be written in a well visible way in the label, attending to the class of standardized fire.

Extinguishing agents

Main item: Fire extinguishing agent

-Water spray: Water spray fire extinguishers are used to protect areas that have a class A (solid fuel) fire risk efficiently and safely.

-Demineralised water: demineralised water extinguishers (3 times distilled – oxygenated in some cases) for class C fires (energised equipment). They are also used for chemical fires or bacteriological hazards. Their typical applications are: air services, apartment buildings, banks, museums, offices, hospitals, computer centers, electronic industries, telecommunication centers, schools, supermarkets, etc.
Does not pollute the environment: does not affect the ozone layer (O.D.P.=0) and does not produce global warming (G.W.P.=0).

-Clean agent: it is not toxic, does not produce respiratory problems and does not leave residues after extinction.
Efficient performance: sleeve designed to provide the operator with greater visibility and easy maneuverability. The nozzle generates a very fine spray that increases the cooling power, does not produce thermal shock or electrical conduction.

-Carbon dioxide extinguisher (carbonic snow).
Water and foam (AFFF): water extinguishers with AFFF under pressure are used to protect areas that have a risk of fire class A (solid fuels), class B (liquid fuels) and class C (flammable gases).
Typical applications: manufacturing plants, gas stations, commercial warehouses, hotels, hospitals, schools, paint and mechanical shops, boiler rooms, chemical industry, oil industry, laboratories, cargo and passenger transportation. :Currently they are the ones of safe use since they do not contaminate the environment, and their content does not harm people or the fauna of the place.

-Carbon dioxide (CO2): Carbon dioxide fire extinguishers are designed to protect areas that contain class B fire risks (combustible liquids and gases), class C (energized electrical equipment).
Typical applications: industries, electrical equipment, homes, transportation, businesses, schools, aviation, garages, etc.

-Universal Chemical Powder – ABC: Dry chemical powder extinguishers (75% monoammonium phosphate and others as sprayed salts) (ABC) are used to fight class A (combustible solids), class B (combustible liquids and gases), class C (energized electrical equipment) fires.

-Dry chemical powder – BC: Dry chemical powder extinguishers are designed to protect areas that contain class B (combustible liquids and gases), class C (energized electrical equipment) fire hazards.
Typical applications: industries, electrical equipment, homes, transportation, shops, schools, aviation, garages, etc.

-Dry chemical powder – D: Dry chemical powder extinguishers (e.g. k-purple) are designed to protect areas containing class D (combustible metals) fire hazards including lithium, sodium, sodium and potassium alloys, magnesium and metal compounds.
It is loaded with sodium borate based composite powder. The compound is treated to make it resistant to the influence of extreme climates by means of hydrophobic silicon-based agents.

Special extinguishing agents

-Halogenated class “H” fire extinguisher in replacement of halon gas (which damages the ozone layer and is only authorized in some military applications), recommended in closed environments without the presence of life or personnel in the area. Suffocating agent (it splits the oxygen).

-Class “N” extinguishers that neutralize gas formation by chemical agents or weapons of mass destruction by propelling micro-sprayed powder with a neutralizing agent into the product read “product-specific antidote”.

Classification of fire extinguishers

The following fire extinguishers are included in this classification

Soda-acid fire extinguisher:

The sodium-acid fire extinguisher has been the most common type of fire extinguisher, in which the extinguishing substance is expelled under pressure. The chemicals involved in its charge are sodium bicarbonate and sulfuric acid. The sodium bicarbonate dissolves in the water contained and this solution constitutes the real extinguishing substance. The concentrated sulphuric acid is contained in a bottle which hangs in the centre of the upper part of the apparatus, closed by a loose glass or ceramic stopper, so that it can easily fall out of its seat in the neck of the bottle.

When the apparatus is put into action, inverting its normal position, the acid and bicarbonate mix chemically producing enough carbon dioxide gas to develop considerable pressure and expel the water giving the jet a range of 10 to 12 meters.

The reaction that takes place can be expressed in the following equation

H2SO4 + 2 NaHCO3 = Na2SO4 + 2 CO2 + 2 H2O

With the fire extinguisher in normal position, the water and bicarbonate level should not exceed the existing mark expressed as “water level”. These fire extinguishers must be recharged annually. When recharging, all parts should be washed with water and water should be pushed through the discharge hose, if available, to wash it perfectly. It is convenient, when performing the annual discharge, to give the personnel the opportunity to perform this operation in the framework of a small fire drill. The annual reloading is recommended because the chemicals deteriorate over time. The bicarbonate solution decomposes slowly letting carbon dioxide gas escape, especially when the extinguisher is exposed to high temperatures. Sulfuric acid absorbs ambient moisture, begins to dilute and may occasionally overflow from its bottle or spill part of its contents during handling. When recharging, the baking soda should be diluted in warm (not hot) water outside the fire extinguisher, in a bucket or container, making sure that the baking soda is well diluted. Then the basket carrying the bottle or jar must be placed and finally the bottle with its cap. Close the device, putting the lid on and it will be ready to work.

Manufacturing characteristics

The fire extinguisher container must be made of iron plate No. 16 or 1.59 mm thick, welded on its longitudinal sides and joints of the dome and bottom. It must be tested under hydraulic pressure, a fundamental operation since internal pressure is created during its operation. If this test is not carried out, there could be a case, already experienced, of welding or pitting of the sheet metal in its weakest part, with the unfortunate consequences foreseeable by the operator or assistant. For this reason, it must be checked that each fire extinguisher has the manufacturer’s guarantee, if the hydraulic test has been carried out.

The hydraulic test for this type of fire extinguisher must be repeated every five years. For them it is necessary to have a pump of sufficient power to develop an internal pressure of 24 atm. for 5 minutes. Wheeled or larger capacity fire extinguishers must be brought to an internal pressure of 27.5 kilograms per square centimetre.

Monthly checks

According to NOM-002-STPS, the current fire protection standard in Mexico, monthly checks of all fire extinguishers in a company must include the following points:

Be at the location assigned in the general plan of the facilities
Fire extinguishers should be located in visible, easily accessible and unobstructed places
They must be marked in accordance with the relevant standards for signage and civil protection
To have a seal or guarantee strip without violating
The pressure gauge must be in the operable zone
In the case of carbon dioxide fire extinguishers, they must have the nominal capacity indicated by the manufacturer
There must be no evidence that they have been activated
In the case of mobile fire extinguishers, their wheels must remain in good condition
-There must be no obvious physical damage such as corrosion, pressure leakage, obstruction, blows or deformation as well as breaks, detachments, holes, etc. that could obstruct its operation
-The label, plate or engraving must be legible and unaltered and must contain the necessary information according to
-To have a collar that establishes the corresponding standard
-To have the record of the monthly revisions.

How to protect fire extinguishers?

If you have just purchased a fire extinguisher for your company, we recommend that you place it inside a fire extinguisher cabinet that will make it better and longer for their premises. There are several ways to protect your fire extinguishers offered by DesignFeu:

Fire extinguisher cabinet:

An ideal complement to protect fire extinguishers that need to be installed outdoors in fixed installations, but also in trucks and other vehicles needed to transport fire extinguishers.
They are also perfect for those environments where aesthetics are important.

Alto double fire extinguihser cabinet

Fire extinguisher stand:

Thanks to the range of fire extinguisher stands we can get them without having to drill holes in the wall.

Here are the advantages and disadvantages of these fire extinguisher stands.

-Easy to transport from one place to another. In case of new works or reforms we can place them once finished.
-They are customizable, as they can be painted in any color and even in gold and chrome.
-Resistant. They are made of carbon steel and painted and treated with hot paint that gives them corrosion resistance.
-Stability. Its design is designed to withstand any dust, water or CO2 extinguisher. The only difference is the type of support to hang it.

Ease of theft. Because they are not subject to any site can be easy to steal.

Plot fire extinguisher stand

Fire extinguisher bracket:

Fire extinguisher holders allow them to be stored and secured in a corridor or specific room so that they do not fall off and are easily visible and identifiable by hanging on the wall.

Plot fire extinguisher bracket

Fire extinguisher cover:

The fire extinguisher cover protects fire extinguishers, leaving them quickly available for emergency use. They increase safety by protecting the fire extinguishers from dirt and aggression. But above all, it allows you to install your fire extinguishers in the most visible and therefore most accessible places without damaging the visual appearance of your premises.

Cintro fire extinguisher cover