Types of Fire Extinguishers

Not all fires are the same, and neither are fire extinguishers. Different extinguishing agents are suited to different types of fires, classified into categories A, B, C, D, and K. Here we explore the common types of extinguishers and their applications:

• Water Extinguishers: Effective against Class A fires involving common combustibles like wood, paper, and textiles. These extinguishers work by cooling the fuel and extinguishing the flames.
• Foam Extinguishers: Suitable for Class A and B fires, ideal for liquid fires involving petrol, oil, and fats. Foam extinguishers form a barrier over the burning liquid, smothering the fire and preventing re-ignition.
• Dry Chemical Extinguishers: Versatile units covering Class A, B, and C fires, perfect for electrical fires and flammable liquids. They work by interrupting the chemical reaction of the fire and can leave a residue that needs to be cleaned after use.
• Carbon Dioxide (CO2) Extinguishers: Preferred for Class B and C fires, especially useful in electrical fire scenarios without leaving residue. CO2 extinguishers work by displacing oxygen, suffocating the fire. They are ideal for use on sensitive electrical equipment.
• Wet Chemical Extinguishers: Specifically designed for Class K fires, such as those involving cooking oils and fats typically found in commercial kitchens. These extinguishers create a cooling, soap-like layer over the burning oil, preventing re-ignition.

Types of Fire Extinguishers: A Complete Guide

Along with ensuring you have the right types of fire extinguisher, you will also need to make sure that you select the right sizes and weights. Read more about the current UK extinguisher regulations.

Distinguishing the Different Classes of Fire

Distinguishing the different classes of fire is incredibly important to fire safety because not all fire extinguishers are suitable for every type of fire. In fact, using a fire extinguisher that isn’t intended for use on a particular class of fire can quickly make the fire worse and pose serious risk to the fire extinguisher’s user and others in the vicinity. Here, we outline the various classes of fire, where they can potentially occur, and which fire extinguishers are suitable for each class of fire.

What Are the Different Classes of Fire?

There are six classes of fire:

• Class A — Fires involving solid combustible materials of organic nature such as wood, paper, rubber, plastics, etc.
• Class B — Fires involving flammable liquids or liquefiable solids (such as petrol, diesel, kerosene, etc).
• Class C — Fires involving flammable gases under pressure including liquefied gases, (like LPG).
• Class D — Fires involving combustible metals such as magnesium, aluminium, zinc, sodium, potassium, etc.
• Class F — Fires involving cooking media (vegetable or animal oils and fats) in cooking appliances and may be called kitchen fire.

The Regulatory Reform (Fire Safety) Order 2005 requires premises to supply adequate fire safety equipment relevant to the risks of the premises. For example, a commercial kitchen or restaurant would be obligated to keep fire extinguishers suitable for Class F fires where an office would not. This is where a fire risk assessment becomes so important as it allows premises to identify which classes of fire they are most at risk of and, as a result, be able to install suitable fire safety measures. Some settings are at greater risk of certain types of fire than others and each class of fire requires a specific type of fire extinguisher to be present.

Different Types of Fire Extinguisher

Each class of fire requires a certain type of fire extinguisher. You can quickly identify a suitable fire extinguisher by its label. The list below concisely highlights which classes of fire various fire extinguishers are suitable for:

• Water fire extinguisher – Class A
• Foam fire extinguisher – Class A and B
• Powder fire extinguisher – Class A, B, C and electrical fires (under 1000v)
• CO2 fire extinguisher – Class B and electrical fires
• L2 fire extinguisher – Class D
• Wet Chemical fire extinguisher – Class A and F
• MultiCHEM fire extinguisher – Class A, B and F
• Water Mist fire extinguisher – Class A and F

Using Fire Extinguishers

Proper use of fire extinguishers is critical for their effectiveness. The PASS technique — Pull, Aim, Squeeze, and Sweep — provides a simple method for operating most extinguishers. Training and regular drills are recommended to ensure individuals are prepared to act in an emergency.

There are a number of different types of portable fire extinguishers, each can be identified by the colour coding and labelling. Check that the extinguisher you intend to use is suitable for the type of fire encountered eg a water extinguisher must never be used on any fire involving electrical equipment.

There are four (4) basic steps for using modern portable fire extinguishers.

The acronym PASS is used to describe these four basic steps:

• Pull (Pin): Pull pin at the top of the extinguisher, breaking the seal. When in place, the pin keeps the handle from being pressed and accidentally operating the extinguisher. Immediately test the extinguisher. (Aiming away from the operator) This is to ensure the extinguisher works and also shows the operator how far the stream travels
• Aim: Approach the fire standing at a safe distance. Aim the nozzle or outlet towards the base of the fire.
• Squeeze: Squeeze the handles together to discharge the extinguishing agent inside. To stop discharge, release the handles.
• Sweep: Sweep the nozzle from side to side as you approach the fire, directing the extinguishing agent at the base of the flames. After an A Class fire is extinguished, probe for smouldering hot spots that could reignite the fuel.

Maintenance and Inspection

Regular maintenance and inspection are crucial to ensure fire extinguishers are in working order when needed. This includes checking the seal, ensuring the pressure is at the recommended level, and looking for any signs of wear or damage. Professional inspections should be conducted annually, with servicing and refills performed as necessary.

Additionally, it's essential to keep records of all maintenance and inspections conducted on fire extinguishers for compliance and liability purposes.

Standards on Fire Extinguishers

Fire extinguishers are essential fire safety devices that can help save lives and property in the event of a fire. They are the first line of defense against small fires and can be used to put out a fire before it has a chance to spread and cause significant damage. Therefore, they are called first-aid fire extinguishers.

BIS has published various standards on fire extinguishers related to their performance, reliability, and safety. Out of these standards, the following two are widely used in various building occupancies and industries:

• IS 15683: 2018 Portable Fire Extinguishers — Performance and Construction — Specification (First Revision)
• IS 16018: 2012 Wheeled Fire Extinguishers — Performance and Construction — Specification

1) Portable Fire Extinguishers

Portable fire extinguishers are immediately available and can be used by one or two persons. The weight of a fully charged portable fire extinguisher shall not be more than 17 kg as per IS 15683: 2018.

2) Wheeled Fire Extinguishers

Wheeled fire extinguisher is a fire extinguishing appliance on wheels having a total mass of more than 17 kg and less than 450 kg (with all accessories), which is designed to be operated and transported to the seat of fire even by one person.

The above extinguishers use any of the following media to extinguish/douse the fire:

• Water;
• Foam;
• Dry Chemical Powders — ABC/BC/D Type;
• Carbon dioxide;
• Clean agents; and
• Water mist.

While the extinguishers are relatively easy to operate and use, based on the mechanism to propel the above extinguishing media, suitable training is recommended by the operating personnel. Depending on the material/object/item under fire, one of the above extinguishing media can be used in the fire extinguishers and marked accordingly on the body of the extinguisher. The Indian Standard defines the above aspects under “classification of fire”.

Based on the classification of fire, extinguishers are marked with specific rating relating to a definite period of time for which the extinguishing media will propel out so as to enable in quenching the fire. Further, based on the threat, amount of combustible material involved, more than one type of extinguishers may have to be installed/used side by side in a building/ occupancy. A separate standard describing the selection, installation, and maintenance criteria namely, IS 2190 is of great help to building professionals.

Licensing Information

Towards ensuring the safety of public and property at large, the Department for Promotion of Industry and Internal Trade, Ministry of Commerce and Industry, Govt. of India has issued a QCO titled ‘the Fire Extinguishers (Quality Control) Order, 2023’. This Order makes it mandatory for any manufacturer of fire extinguishers of the above two types to essentially conform their products (extinguishers) to the above-mentioned Indian Standards. As per the Order, the extinguisher manufactured henceforth shall bear a Standard Mark (Mark) under a valid licence from the Bureau of Indian Standards (BIS).

• The QCO was notified through Gazette on 9 August 2023 and comes into force with effect from six months from the date of publication of the notification. For Micro enterprises, as defined under the Micro, Small and Medium Enterprises Development Act, 2006 (27 of 2006), the QCO will come into force with effect from twelve months from the date of publication of the QCO and for Small Enterprises, as defined under the Micro, Small and Medium Enterprises Development Act, 2006 (27 of 2006), it will come into force with effect from nine months of date of publication of QCO.
• QCOs are issued by the Government of India exercising the powers conferred by section 16 of the BIS Act, 2016, stipulating conformity of the products to Indian Standards. QCOs ensure the quality and safety of products for consumer use. So far, there are 556 products (as on 18th Sept 2023) brought under compulsory certification of BIS that can be manufactured, imported, distributed, sold, hired, leased, stored or exhibited for sale only with BIS Standard Mark under a valid licence from BIS.

Placement and Accessibility

Strategic placement of fire extinguishers is essential for quick access during an emergency. Extinguishers should be located near exit routes, in areas at high risk for fires, and visibly marked. Ensuring clear instructions are provided for each type of extinguisher can also greatly improve the effectiveness of response efforts.

Regular checks should be made to ensure extinguishers are not obstructed or hidden from view. Proper signage and lighting can further enhance visibility and accessibility.