Introduction to Health and Safety at Work

13.6.4 Direct 
burning
This is the effect of combustible materials catching fi re 
through direct contact with fl ames which causes fi re to 
spread, in the same way that lighting an open fi re, with 
a range of readily combustible fuels is spread within a 
grate.
13.6.5 Smoke spread in buildings
Where fi re is not contained and people can move away 
to a safe location there is little immediate risk to those 
people. However, where fi re is confi ned inside buildings 
the fi re behaves differently (Figure 13.4).
The smoke rising from the fi re gets trapped inside 
the space by the immediate ceiling then spreads 
horizontally across the space deepening all the time 
until the entire space is fi lled. The smoke will also pass 
through any holes or gaps in the walls, ceiling or fl oor 
and get into other parts of the building. It moves rapidly 
up staircases or lift wells and into any areas that are left 
open, or rooms which have open doors connecting to 
CONDUCTION
CONVECTION
RADIATION
Decomposition
and/or
vaporization
Heated air rises
Figure 13.3
Principles of heat transmission.
Figure 13.4
Fire spread in buildings.

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Introduction to Health and Safety at Work
208
the staircase corridors. The heat from the building gets 
trapped inside, raising the temperature very rapidly. The 
toxic smoke and gases are an added danger to people 
inside the building who must be able to escape quickly 
to a safe location.
13.7 
Common causes of fi re and 
consequences
13.7.1 Causes
The Home Offi ce statistics show that the causes of fi res 
in buildings, excluding dwellings, in 2001 was as shown 
in Figure 13.5. The total was 43 600, a rise of 4% from 
the previous year but below the ten-year peak of 47 900 
in 1995. The majority of fi res occurred in:
➤
Private garages and sheds 20% (8900 fi res)
➤
Retail distribution 13% (5700 fi res)
➤
Industrial premises 10% (4500 fi res)
➤
Restaurants, cafes, public houses etc 8% (3400 fi res)
➤
Hospitals 7% (3000 fi res)
The sources of ignition are shown in Figure 13.6. Out of 
the 23 800 accidental fi res in 2001, it shows that cooking 
appliances and electrical equipment account for nearly 
50% of the total. Malicious fi res increased by 10% up 
to 19 700, although this is still 12% lower than the 1994 
peak of 22 400.