Introduction to Fire Safety Management

Figure 7.17
Smoke spread – convection
7.4.2 Conduction
Conduction is the movement of heat through a mater-
ial. The ability of conductors to transfer heat varies 
Figure 7.18
Fire spread through a fi re resisting wall by 
conduction along a steel pipe
7.4.3 Radiation
Radiation is the transfer of heat energy as electro-
magnetic waves, which heat solids and liquids (but not 
gases) encountered in its path.
Fire radiation paths do not require any contact 
between bodies and move independently of any material 
in the intervening space. If not absorbed by fi re resist-
ant material the electromagnetic radiation can radiate 
through glazing causing fi res to spread and involve a 
number of compartments/rooms. As with the example 
of a heater or open fi re, fi res can spread to combust ible 

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Introduction to Fire Safety Management
124
items left to dry or from building to building when heat 
from a fi re may be radiated to an adjacent building by 
passing through windows, and igniting combustible 
contents in the second building.
heated to an ignition temperature by coming into con-
tact with a burning material causes fi re to spread.
7.4.5 Fire 
growth
The rate at which a fi re grows will depend upon numer-
ous factors and it should be noted that a single factor 
on its own may not promote fi re growth but interreacting 
factors may develop a fi re more rapidly. A rapid growth 
rate will have an effect upon areas such as the stability 
of the building and the effectiveness of the emergency 
plan to ensure that people can leave the building safely.
The fi re growth rate is generally recognised as the 
rate at which it is estimated that a fi re will grow; this 
includes spread of fl ame over surfaces and behind 
linings, and within any part of the contents. Fire growth 
rates may be categorised in accordance with Table 7.2.
Factors that may affect the growth rate include the:
➤
Construction and layout of the building
➤
Ventilation into, throughout and out of the building
➤
Use of the building (including the types of activity 
being undertaken)
➤
Fire loading within the building.