Civil Engineering Reference
In-Depth Information
The selection of incorrect plant and equipment for
use in hazardous areas where a fl ammable or explosive
atmosphere can also have the potential to cause a fi re
or explosion.
As arson is dealt with in a section on its own within this
section the fi rst area to be addressed will be electrical
causes of fi re.
8.2.1
Temporary electrical installations
8.1.9 Vehicle fi res
While similar in nature to electrical systems utilised
within permanent structures those used in construction
and maintenance operations are subject to potentially
more arduous or hostile environments.
Some common electrical faults in construction and
maintenance operations that pose fi re hazards include:
Accidental fi res involving vehicles can occur for a number
of reasons, these are generally due to:
➤
Faulty wiring looms or components
➤
Fuel leakage
➤
Discarded smokers' materials
➤
Faulty HT systems (ignition systems)
➤
The overloading of electrical sockets and systems in
site accommodation
➤
Hot exhaust contact with combustible materials
➤
Vehicle collisions or accidents.
➤
The incorrect use of fl at twin and earth cable as
extension leads instead of suitable fl exible cable
Modern vehicle interiors are largely composed of poly-
mers, plastics and other synthetic materials - all of
which are particularly combustible giving off fl ammable
vapours. The smoke and fumes from the outbreak of fi re
are highly toxic and can be deadly if inhaled.
Poorly conducted and managed refuelling or
recharging arrangements for vehicles can also cause
fi res. Overcharging of batteries (e.g. forklift trucks) can
release hydrogen which has a very wide explosive range
and refuelling a petrol driven vehicle in close proximity
to ignition sources also has the potential to cause a fi re.
Vehicle fi res can also be a primary source for a
secondary fi re in a building, e.g. delivery/haulage vehicle
within a distribution depot, or a forklift truck within a
warehouse, where a fi re starting from a vehicle quickly
spreads within a building causing the whole building to
be involved.
➤
Electrical cables or lighting laid on or near combust-
ible material (frequently in roof and ceiling voids)
➤
Mechanical damage to cables, often as a result of
inappropriate routing of cables
➤
The intentional defeating of safety devices, such as
fuses or circuit breakers (use of metal objects such
as nails)
➤
The accumulation of combustible rubbish against
temporary distribution boards and transformers
➤
Unauthorised make-shift cable joints made without
correct proprietary connectors.
In addition to the above issues fi res have been started
by inappropriate location of temporary site and task
lighting particularly when using halogen lighting sys-
tems in close proximity to fl ammable or combustible
materials.
8.2
Causes of fi re relating to
construction and maintenance
Many of the causes of fi re detailed above can relate to
work involving construction and maintenance oper-
ations. Equally the preventive measures that may be
adopted to minimise the risk of a fi re occurring in con-
struction and maintenance operations may be equally
valid across many sectors of industry. This section of the
topic will look at specifi c causes of fi res in construction
and maintenance operations.
A large proportion of fi res started within the
construction sector fall under the following key headings:
➤
Arson
➤
Electrical
➤
Hot work
➤
Flammable and combustible substances.
Figure 8.6
Typical hot works include welding
