Choosing Fire
Extinguishers.
Identify
the type of materials in the area.
Class A: SOLIDS such as paper, wood, plastic etc
Class B: FLAMMABLE LIQUIDS such as paraffin, petrol,
oil etc
Class C: FLAMMABLE GASES such as propane, butane,
methane etc
Class D: METALS such as aluminium, magnesium, titanium
etc
Class E: Fires involving ELECTRICAL APPARATUS
Class F: Cooking OIL & FAT etc
Types of fire extinguisher.
Water
Fire Extinguishers:
The cheapest and most widely used fire extinguishers. Used
for Class A fires. Not suitable for Class B (Liquid) fires,
or where electricity is involved.
Foam
Fire Extinguishers:
More expensive than water, but more versatile. Used for
Classes A & B fires. Foam spray extinguishers are not
recommended for fires involving electricity, but are safer
than water if inadvertently sprayed onto live electrical
apparatus.
Dry Powder Fire
Extinguishers:
Often termed the multi-purpose extinguisher, as it can be
used on classes A, B & C fires. Best for running liquid
fires (Class B). Will efficiently extinguish Class C gas
fires, BUT BEWARE, IT CAN BE DANGEROUS TO EXTINGUISH A GAS
FIRE WITHOUT FIRST ISOLATING THE GAS SUPPLY. Special
powders are available for class D metal fires.
Warning: when used indoors, powder can obscure vision or
damage goods and machinery. It is also very messy.
CO2 Fire Extinguishers:
Carbon Dioxide is ideal for fires involving electrical
apparatus, and will also extinguish class B liquid fires, but
has NO POST FIRE SECURITY and the fire could
re-ignite.
Wet
Chemicals.
Specialist extinguisher for class F fires.
For Metal Fires: A specialist fire extinguisher for use on
Class D fires - metal fires such as sodium, lithium,
manganese and aluminium when in the form of swarf or
turnings.
Color
Coding.
the code of practice for fire extinguishers in the UK was BS
5423, which advised the colour coding of fire extinguishers
as follows:
Water - Red
Foam - Cream
Dry Powder - Blue
Carbon Dioxide (CO2) - Black
Halon - Green (now 'illegal' except for a few exceptions such
as the Police, Armed Services and Aircraft).
New extinguishers should conform to BS EN 3, which requires
that the entire body of the extinguisher be coloured red. A
zone of colour of up to 5% of the external area can be used
to identify the contents using the old colour coding shown
above.
