INTRODUCTION
The fire incidences are among the most serious disasters impacting human lives as well as property. Many wrong and misleading information on “Classification of Fires and Fire Extinguishers” are available online which are not as per Indian Standards as details given in table below. This leads to confusion over correct selection of fire extinguishers based on material on fire (fuel), since all available fire extinguishers in India are being manufactured as per Indian Standards. If wrong type of fire extinguisher is used for extinguishing the fire, it might make matters worse.
Material on Fire
Indian UK/ standard Europe
US Australian
Solid combustible materials of Class A Class A organic nature
Class A Class A
Flammable liquids
Combustible metals
Energised electrical conductors/ equipment
Class B
Class D No class
Class B Class B Class B
Class D Class D Class D No class
Flammable gases under Class C Class C pressure
Class C
Cooking media (Kitchen Fire) Class F Class F
Class B
Class K
Class C
Class F
Class E
OBJECTIVE OF THIS PAMPHLET
 To create awareness among the field staff to use appropriate fire extinguishers according to the nature of material on fire (fuel).
 To give correct information related to “Classification of Fires and Fire Extinguishers” according to Indian Standards (IS 15683:2018 & IS 2190:2010).
 To give information related to fires involving energized electrical equipment with correct identification of fire extinguishers for mitigation of fire.
 Also to give information related to fire extinguishers appropriate for fires in areas where presence of sensitive electrical and electronic equipment such as control rooms, computers, relay circuits.

CHARACTERISTICS OF FIRE (Fire Triangle)
The fire requires three elements to ignite: heat, fuel, and an oxidizing agent (usually oxygen).
By eliminating any one of the element, fire can be extinguished.
CLASSIFICATION OF FIRE ACCORDING TO
TYPE OF FUEL(Ref: para 3.1 of IS 15683 : 2018 & para 9 of IS 2190:2010)
Fires are classified according to the type of fuel that is burning, which is as under:
Class of Fire
Symbol
Definition
Class A
Fires involving solid combustible materials of organic nature such as wood, paper, rubber, plastics, etc. where the cooling effect of water is essential to extinguish the fire.
Class B
Fires involving flammable liquids or liquefiable solids or the like where a blanketing effect is essential to extinguish the fire.
Class C
Fires involving flammable gases under pressure including liquefied gases, where it is necessary to inhibit the burning gas at fast rate with an inert gas, powder or vaporizing liquid for extinguishment.
Class D
Fires involving combustible metals such as magnesium, aluminium, zinc, sodium, potassium etc., when the burning metals are reactive to water containing agents and in certain cases carbon dioxide, halogenated hydrocarbons and ordinary dry powders. These fire require special media and techniques to extinguish.
Class F
Fires involving cooking media (vegetable or animal oils and fats) in cooking appliances and may be called kitchen fire.
No class
Where fire involves energized electrical equipment.

ELECTRICAL FIRES
(Ref: para 9 of IS 2190 : 2010 and para 10.2.3 of IS 15683 : 2018)
In Indian Standards, Electrical fires (fires involving energised electrical conductors/ equipment) are not given specific class, as they can fall into any of the classifications as per the material on fire (fuel). Electricity may initiate fire but it is not the electricity that is burning but surrounding material that has been set alight. For example, if a computer will burn due to a short circuit, then the computer is on fire and not electricity. In de-energised condition, this is then class A fire.
Therefore, it is important to decide selection and use of extinguisher on live electrical installations. The extinguisher that have passed electrical conductivity test should only be used on fires involving energised electrical conductors/equipment and fire extinguishers shall have this symbol marked on it.
Dealing with Electrical Fires
 Fire extinguishers with Class C ratings shall be required where energized electrical equipment can be encountered. This requirement includes situations where fire either directly involves or surrounds electrical equipment. Since the fire itself is a Class A or Class B hazard, the fire extinguishers shall be sized and located on the basis of the anticipated Class A or Class B hazard. (Ref: para 5.4.3 of IS 2190 : 2010)
Where energized electrical equipment is involved in a fire, non- conductivity of the extinguishing media is of utmost importance, and only extinguishers expelling dry powder, carbon dioxide (without metal horn) or clean agent should be used. Once the electrical equipment is de- energized, extinguishers suitable for the class of the fire risk involved can be used safely. (Ref: para 10.2 of IS 2190 : 2010).
Where cleanliness and contamination of sensitive electrical equipment are of importance or where the sensitivity of the control instruments or electronic equipment and systems are likely to be affected, only Carbon Di-oxide or Clean Agent type extinguishers should be used. (Ref: para 10.3 of IS 2190 : 2010).

TYPES OF FIRE EXTINGUISHERS (PORTABLE)
(Ref: para 4 of IS 15683 : 2018)
Portable fire extinguishers are not expected to deal with large fires but, these are very valuable if used promptly and efficiently in the early stages of fire. Extinguishers are labelled with either letter-shaped or pictorial symbols that indicate what types of fires the extinguisher is designed to fight.
Fire Extinguishers may be classified by the type of extinguishing medium which they contain. At present, the main types of extinguishers are:
Water based
Foam based
Powders based — ABC/BC/D Type Carbon dioxide
Clean agents and
Water mist type
TYPES
Water or APW (Air-Pressurized Water) based Fire Extinguishers
Extinguishing Media – Water and Water Mist
APWs extinguish fire by taking away the “heat” element of the Fire Triangle.
Note: Water extinguishers can be very dangerous in the wrong type of situation. Only fight the fire if you’re certain as it contains ordinary combustible materials only.
 Suitable for – CLASS A (Wood, paper, cloth etc.) fires

Foam based Fire Extinguishers
They spray a type of foam (mixed with water) that expands when it hits the air and blankets the fire.
This blanket prevents the vapours from rising off the liquid to feed the fire, thus starving it of fuel. Also, because the foam is mixed with water, it has a cooling effect as well.
Extinguishing Media – foam (mixed with water)
 Suitable for – class A and class B (flammable liquids)
Dry Chemical Powder (DCP) Based Fire Extinguishers
Extinguishing Media – Dry Chemical Powder
Suitable for – suitable for a combination of Class A, B, C fires.
• The greatest portion of this powder is composed of Mono Ammonium Phosphate (MAP) and the extinguishers are pressurized with nitrogen.

• Dry chemical extinguishers put out fire by coating the fuel with a thin layer of dust. This separates the fuel from the oxygen in the air.
• The powder also works to interrupt the chemical reaction of fire. These extinguishers are very effective at putting out fire.
• DCP fire extinguishers are available in variety of types and are suitable for a combination of Class A, B, C fires.
• It is extremely important to identify which types of dry chemical extinguishers are available at the site.
• DCP (Dry Chemical Powder) extinguishers have an advantage over CO2 extinguishers since that leave a non-flammable substance on the extinguished material, reducing the likelihood of re-ignition.
  Note: Dry powder extinguishers, when used in confined areas may reduce visibility for a few minute, which may temporarily jeopardize escape, rescue or other emergency action. (Ref: 10.5 of IS 2190:2010) Carbon Dioxide (CO2) Based Fire Extinguishers
  • Carbon dioxide is a non-flammable gas that takes away the oxygen element of the fire triangle. Without oxygen, there is no fire.
• CO2 is very cold as it comes out of the extinguisher, so it cools the fuel as well.
• The pressure in this extinguisher is so great that it is not uncommon for bits of dry ice to shoot out the nozzle/horn.
• A CO2 may be ineffective in extinguishing a Class A fire because it may not be able to displace enough oxygen to successfully put the fire out, causing it to re-ignite.
• CO2 extinguishers have an advantage over DCP since they don’t leave a harmful residue, therefore it is a good choice for an electrical fire on sensitive electrical equipment, control instruments or electronic equipment where cleanliness and contamination of are of importance.
  Extinguishing Media – Carbon Dioxide (CO2), a non-flammable gas
  Suitablefor -suitableforClassBandCfires
  Clean Agents Based Fire Extinguishers (Ref: para 3.13 of IS 15683 : 2018)
  • Clean Agents are electrically non-conductive gaseous or vaporizing liquid fire extinguishant that does not leave a residue upon evaporation and are not toxic to level of concentration at which it extinguishes the fire.
• Clean agents are halon substitutes such as HFC, HCFC, HBFC, their blends and fluoro- ketone, etc.
• Name of clean agent shall be marked on the label of the extinguishers.

Wet Chemical extinguisher
 Wet chemical fire extinguisher is specially designed for CLASS F FIRES, those involving cooking media such as animal and vegetable fats or oils.
 These extinguishers contain a solution composed of Potassium that effectively launches a two-pronged assault on fires:
 First, the liquid mist, it sprays acts to cool the fire.
 Second, due to the chemical reaction of the solution with the cooking medium, a thick soap- like substance forms, sealing the surface of the liquid to prevent re-ignition.
SPECIAL FIRE EXTINGUISHERS
Fire Suppression Balls
(Ref: Rly. Bd. L. No. 2001/Elect (G)/113/4/Safety dated 07.01.2021)
 These are “Self activating Fire Extinguishing balls” and they contain MAP (Mono Ammonium Phosphate) in range of 90 to 95%.
 These fire extinguishing balls are a good low cost source to control spread of fire.
 Whenever these balls come in contact with fire, they burst automatically means even if the place of probable fire is unmanned, after start of fire, these balls will burst without any manual intervention.
 These fire balls may be used in electrical sub-stations, workshops, in coal or metal mines, oil mines etc.

Automatic Cylinder-less Fire Detection & Suppression Tube System
MARKING AND COLOUR
(Ref: para 10.1 of IS 15683 : 2018)
Extinguishers
Water based/ Water mist extinguishers
Band Colour
Red
Foam based extinguishers
Powder based extinguisher
Yellow
Blue
Carbon dioxide based extinguishers
Clean agent extinguishers
Black
Green
 



This system consists of a heat sensitive tube made of special plastic which is closed by a stainless steel fitting on each end.
The tube has both storage and detection function which means that the extinguishing agent is stored directly in the tube and no additional storage device such as cylinder is needed.
The system is suitable for protection of small enclosures with greater risk of fire such as electrical panels, server racks, tele-communication cabinets etc.
It operates automatically without any power supply by detecting higher temperatures. When the temperature in the protected enclosure rises to a critical threshold (between 95oC-120oC temp), the heat sensitive tube melts / ruptures down at the point where the affecting temperature is the highest.
Melting of the tube creates a hole releasing the entire extinguishing agent stored in the tube directly onto the source of the fire.
The recommended colour for extinguisher bodies is RED. A small band of distinguishing colour of approx. 5 percent/prominent of surface area shall be painted for different type of extinguishers as given below: S.N.

1.
2.
3.
4.
5.
6.
Class A
Class C
Class D
SUITABILITY OF DIFFERENT TYPES OF FIRE
EXTINGUISHERS
(Ref: Table 3 of IS 2190:2010)
Type of Extinguisher
Water type (gas cartridge or stored pressure)
Mechanical foam type (gas cartridge or stored pressure)
Dry powder type (gas cartridge or stored pressure)
Dry powder type for metal fires
Carbon dioxide type
Clean agent gas type
Material on Fire i.e. Fuel
(Ref: para 3.1 of IS 15683: 2018 & para 9 of IS 2190:2010)
NO
NO
A
YES
YES
YES
YES
Class of Fire
NO
NO
B
YES
YES
YES
YES
NO
NO
NO
C
YES
YES
YES
NO
D
NO
NO
YES
NO
NO
SUMMARY OF FIRE CLASSES & TYPES OF FIRE EXTINGUISHERS
Fire Class
Suitable type of Fire Extinguisher
(Ref para 10.1 of IS 2190:2010)
Ordinary combustible solids such as wood, paper, rubber, plastics, furniture, curtains etc.
Flammable gases under pressure including liquefied gases such as LPG, natural gas, propane, methane etc.
water, foam, ABC dry chemical powder and halo carbons extinguishers
Class B
Flammable liquids or liquefiable solids such as petrol, diesel oil, acetone, wax etc.
Foam, dry chemical powder, clean Agents and carbon dioxide (CO2) extinguishers
Dry chemical powder, clean Agents, and carbon dioxide (CO2) extinguishers
Combustible metals such as magnesium, aluminium, zinc, sodium, potassium, etc.
Extinguishers with special dry powder suitable for metal fires
Class F
(Kitchen Fire)
Cooking media such vegetable or animal oils and fats etc.
Energised electrical conductors / equipment involved in fire
Wet chemical fire extinguisher
non-conducting extinguishing media such as dry chemical powder, carbon dioxide (without metal horn) or clean agent.

POINTS TO BE INSPECTED FOR FIRE
EXTINGUISHERS
(Ref: Para 11 of IS 2190:2010)
Periodic inspection of fire extinguishers shall include a check of at least the following items:
a. Location in designated place.
b. No obstruction to access or visibility.
c. Operating instructions on nameplate legible and facing outward.
d. Safety seals and tamper indicators not broken or missing.
e. Fullness determined by weighing or lifting.
f. Examination for obvious physical damage, corrosion, leakage, or clogged nozzle.
g. Pressure gauge reading or indicator in the operable range or position.
h. Condition of tyres, wheels, carriage, hose, and nozzle checked (for wheeled units).
Maintenance, servicing, and recharging shall be performed by trained persons and Record of the date of inspection, recharging, etc. should be maintained in the register.
SELECTION OF LOCATION (Ref: para 6 of IS 2190 : 2010)
 When selecting locations for fire extinguishers, due consideration should be given to the nature of risk to be covered. Ex. Class of Fire risk involved.
 The extinguishers should be placed in visible positions and shall be readily accessible for immediate use in all parts of occupancy.
 Generally, fire extinguishers should be placed as near as possible to exits or stair lands without hindering the escape routes.

 Extinguishers should be sited in such a way that the user may not have to travel more than 15 m from the site of the fire to reach the extinguishers.
Pull
Aim
HOW TO USE A FIRE EXTINGUISHER(PASS)
The use of a portable fire extinguisher, can be remembered easily as the PASS method. Using a fire extinguisher requires just 4 easy steps, each represented by a letter in the word PASS:
Squeeze
Sweep
Pull the safety pin on the extinguisher.
Aim the hose of the extinguisher at the base of the fire.
Squeeze the top handle/ trigger/ lever to discharge the extinguishing material/ media.
Sweep the nozzle from side to side (slowly) until the fire is completely out.
Hold the extinguisher with the nozzle pointing away from you and release the locking mechanism.
This will allow you to discharge the extinguisher.
If you aim at the flames (which is frequently the temptation), the extinguishing agent will fly right through and do no good. You need to hit the fuel.
This depresses a button that releases the pressurized extinguishing agent in the extinguisher.
Remember to squeeze it slowly and evenly, so the extinguisher is as effective as possible.
Start using the extinguisher from a safe distance away, then move forward. Once the fire is out, keep an eye on the area in case it re- ignites.
REFERENCES

1. IS 15683 : 2018 (First Revision) – Specification for Portable Fire Extinguishers – Performance and Construction.
2. IS 2190 : 2010 (Reaffirmed 2020) – ‘Code of practice for selection, installation and maintenance of first-aid fire extinguishers’.
   Disclaimer:
   It is clarified that this pamphlet does not supersede any existing provisions laid down by Indian Standards, Railway Board, RDSO or Zonal Railways. The pamphlet is for guidance only and it is not a statutory
   document.
   If you have any suggestion or comment, please write to:
   Jt. Director (Electrical), CAMTECH, Maharajpur, Gwalior (M.P.) – 474 005