Introduction to Fire Safety Management

Number
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20
15
10
5
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Electrical Cooking Spread from
outside
Supposed cause of fire
Figure 8.1 Causes of accidental fi res in industry 2004/2005
heats up and melts the insulation and can set fi re to
fl ammable material nearby. Commonly found in fl exible
cables or cords, or consumer panel/power board leads.
Over recent years there have also been a number of fi res
involving electrical extension leads, where the cable
has remained fully wound on the cable drum. The fl ow
of electricity and the tightness of the fully wound cable
prevent heat dissipation causing overheating and a fi re
to start.
Loose wiring connections – the current fl owing through
the wiring encounters resistance at the connection and
generates heat. This can start a fi re in the wall at the
back of a power point or socket, in a wiring junction box
in the ceiling, above light fi ttings or inside a switch/fuse
board or consumer panel.
Electrical ‘arcing’ (or sparking) – this generally occurs
where wiring insulation has been damaged by an external
occurrence perhaps due to poor location (e.g. under
fl oor coverings). This deterioration to the insulation
allows the copper conductors inside the cable to touch
one another briefl y, or to just make contact with the
metal case of an appliance.
A small current will then fl ow from the ‘live’ conductor
to the neutral or earth wire, or to the earthed
metal case. The current will initially be too small to
blow a fuse or to trip a circuit breaker, but because the
contact area is also very small (a few strands of wire) the
heat produced at this point can reach suffi ciently high
temperatures to melt or vaporise metals such as copper,
brass or sheet metal. The localised heating or energy
release will ignite combustible materials in close proximity
and start a fi re.
The above-mentioned arcing faults are ‘uncontrolled’
whereas arc welding makes use of this energy release
and is an example of ‘controlled’ arcing, which will be
discussed later in this chapter in fi re hazards during
construction and maintenance work.
The Causes of Accidental Fires May 2004–April 2005
(that resulted in loss of over £250 000)
Causes and prevention of fi re
Electrical
Smoking materials
Friction, sparks
Naked light
Cooking
Spontaneous ignition
Heating
LPG cutting
Spread from outside
Figure 8.2 Electrical equipment involved in a school fi re
Poorly maintained equipment, unauthorised use
or maintenance of electrical systems, components and
equipment, lack of formal and informal checks and
inspections can all be directly linked to causes of fi res
within the workplace.
Fires have been known to have been caused by
vermin such as rats eating through electrical cables
within basement areas due to a lack of vermin control
procedures.
8.1.2 Cookers, associated cooking equipment
and installations
Cookers, cooking equipment or other equipment or
installations used for the heating of food provide a range
of sources of ignition and fuel have the potential to initiate
and exacerbate a fi re.
Electrical fi res associated with cooking fall under the
category already covered in the previous paragraph and
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