Introduction to Fire Safety Management

Principles of fi re and explosion
125
include basements. On these occasions, refl ected 
radiated heat, due to the lack of height available, will 
develop the fi re more rapidly and raise the growth rate.
The use of sandwich panel walling, containing 
polystyrene (used as thermal insulation for areas such 
as cold storage facilities), has historically resulted in 
rapid fi re growth, due to the substantial heat release of 
the building material, i.e. the polystyrene. The failure of 
component parts, due to the rapid fi re growth rate of the 
materials, also has the ability to destabilise the panels 
and cause premature collapse.
Whether included as part of the building construc-
tion or as part of the contents of a building, wall and 
surface lining materials also have a direct effect upon 
fi re growth rates.
Approved Document B of the Building Regulations 
classifi es performance of internal linings. These will be 
discussed in future chapters; however, the principles 
involve ensuring that the internal linings should adequately 
resist the spread of fi re over their surfaces and, if ignited, 
a rate of heat release which should be reasonable in the 
circumstances.
In this paragraph ‘internal linings’ means the mater ials 
lining any partition, wall, ceiling, or other internal lining, 
such as plasterboard, plaster wall coverings including 
paper. Clearly hessian and materials such as polystyrene 
tiles have the ability to release large volumes of heat and 
thus would greatly affect fi re growth, whereas plaster, 
plasterboard, etc. release heat very slowly and would not 
adversely affect the fi re growth rate.
Ventilation
As previously discussed the supply of oxygen is critical 
to the development and spread of a fi re. Fire growth rate 
is inextricably linked to the supply of oxygen and there-
fore affected by the ventilation of a building. Air condi-
tioning and air circulation systems provide a fi re with 
a ready source of oxygen via forced ventilation, which 
will aid fi re growth. The presence of dust, vapours and 
fumes within the atmosphere also have the ability to 
affect the fi re growth rate in so far as they provide a rich 
source of fuel. It should also be noted that appropriate 
levels of dust in the atmosphere may cause an explo-
sion; this subject is discussed later in this chapter.
When mechanical smoke extraction systems are 
utilised within a building the effect of fi re growth is 
notably less. The smoke laden air containing particles 
of fuel and substantial quantities of heat is removed 
from the atmosphere by the extraction system reducing 
the speed at which a fi re grows, while assisting smoke 
ventilation and allowing persons clear, smoke-free, 
escape routes.
Use
The use of a building is directly related to the type of 
occupancy. Building use can be categorised in the 
following groups:
➤
Offi ces and retail premises
➤
Factories and warehouse storage premises
➤
Sleeping accommodation such as hotels, boarding 
houses, etc.
➤
Residential and nursing homes
➤
Teaching 
establishments
➤
Small and medium places of assembly – public 
houses, clubs, restaurants, etc.
➤
Large places of assembly (more than 200 persons) – 
shopping centres, conference centres, etc.
➤
Theatres and cinemas