Fire Safety Regulations Guide

Evaluate the Risk to People from Fire

In Step 2 you identified the people likely to be at risk should a fire start anywhere in the premises and earlier in Step 3 you identified the chances of a fire occurring.

It is unlikely that you will have concluded that there is no chance of a fire starting anywhere in your premises so you now need to evaluate the actual risk to those people should a fire start and spread from the various locations that you have identified.

While determining the possible incidents, you should also consider the likelihood of any particular incident; but be aware that some very unlikely incidents can put many people at risk.

To evaluate the risk to people in your premises, you will need to understand the way fire can spread. Fire is spread by three methods:

  • convection
  • conduction
  • radiation.


Fire spread by convection is the most dangerous and causes the largest number of injuries and deaths. When fires start in enclosed spaces such as buildings, the smoke rising from the fire gets trapped by the ceiling and then spreads in all directions to form an ever-deepening layer over the entire room space. The smoke will pass through any holes or gaps in the walls, ceiling and floor into other parts of the building. The heat from the fire gets trapped in the building and the temperature rises.


Some materials, such as metal shutters and ducting, can absorb heat and transmit it to the next room, where it can set fire to combustible items that are in contact with the heated material.


Radiation heats the air in the same way as an electric bar heater heats a room. Any material close to a fire will absorb the heat until the item starts to smoulder and then burn.

Smoke produced by a fire also contains toxic gases which are harmful to people. A fire in a building with modern fittings and materials generates smoke that is thick and black, obscures vision, causes great difficulty in breathing and can block the escape routes.

It is essential that the means of escape and other fire precautions are adequate to ensure that everyone can make their escape to a place of total safety before the fire and its effects can trap them in the building.

In evaluating this risk to people you will need to consider situations such as:

  • fire starting on a lower floor affecting the only escape route for people on upper floors or the only escape route for people with disabilities;
  • fire starting in a service room and affecting hazardous materials (such as pyrotechnics or gas cylinders);
  • fire developing in an unoccupied space that people have to pass by to escape from the building;
  • fire spreading rapidly through the building because of combustible structural elements and/or large quantities of combustible goods;
  • rapid vertical fire spread in high rack storage;
  • fire or smoke spreading through a building via routes such as vertical shafts, service ducts, ventilation systems, poorly installed, poorly maintained or damaged, walls, partitions and ceilings;
  • fire and smoke spreading through a building due to poor installation of fire precautions, e.g. incorrectly installed fire doors or incorrectly installed services penetrating fire walls; and
  • fire and smoke spreading through the building due to poorly maintained and damaged fire doors or fire doors being wedged open.
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