Question

This is Research Work:::
Find out the working of a foam - type fire extinguisher and write a paragraph about it

Answer 1

It is extremely effective because of the clever way the ingredients in a foam fire extinguisher work together. These are concentrated foam solution, water and inert nitrogen, which pressurises the extinguisher. When the extinguisher is used, the stored pressure drives out the foam solution, which swirls around in the nozzle, producing a fine spray of foam in a much larger volume than the extinguisher itself.

# How does it work?
In two ways. The foam seals the fire from its oxygen supply, and secondly the moist foam cools the burning material.

The foam extinguisher colour is usually red with a cream label saying ‘foam’, which conform to British Standard EN3. Stainless steel extiguishers are available for use in design-led or clean environments – but they will still have that cream label. Beware: older foam fire extinguishers aren’t red, but are completely cream. These don’t conform to the EN3 standard, and ought to be replaced and disposed of in an environmentally-friendly way. Your fire extinguisher supplier should be able to do that for you.

Foam fire extinguisher facts

• Also called AFFF extinguishers, which stands for Aqueous Film Forming Foam
• Foam fire extinguishers work by building a non-combustible chemical ‘seal’ that cuts off a fire’s oxygen supply
• Much more effective than water alone
• Lighter than the equivalent water extinguisher
• Available in stainless steel for design or hygiene-led locations
• Not recommended for use close to live electrical appliances, because they contain a quantity of water

Foam fire extinguisher uses

What is a foam fire extinguisher used for?
Fighting fires of Class A (solids such as wood or paper) and Class B (flammable liquids) at locations including:

• aircraft
• oil refineries
• garages
• forecourts
• workshops
• small industrial locations
• motorsport
• boating
• caravanning

How to use a foam fire extinguisher

• DO spray just above the surface of the fire to allow foam to build up and flow over the fire
• DO spray towards the back of a container containing burning liquid or against a vertical surface behind it
• DO use a gentle side-to-side sweeping motion to cover the whole fire
• DO NOT approach the fire too closely
• DO NOT spray directly onto burning liquid. This pushes the foam beneath the liquid, where it can’t put out the fire, but could spread it to a wider area

Answer 2

Answer:

Foam fire extinguishers can be used on Class A and B fires. They are most suited to extinguishing liquid fires such as petrol or diesel and are more versatile than water jet extinguishers because they can also be used on solids such as wood and paper.

Explanation:

Foam fire extinguisher works by smothering the fire and sealing in the flammable vapors. This prevents the fire re-igniting. It also allows foam fire extinguishers to put out flammable liquid fires, by creating a barrier between the liquid's surface and the flames.