Chapter 8: MEANS OF ESCAPE

149. Once a fire has started, been detected and a warning given, everyone in the premises should be able to move or be assisted to move away from the fire to a place of reasonable safety such as a protected stair. From there they should be able to continue to escape to an unenclosed safe area beyond the premises before being affected by fire or smoke. Sufficient means of escape should be provided for persons using the premises, both in terms of the number of escape routes and capacity and in terms of protection by enclosure from fire and smoke. Escape must also be considered from external areas like enclosed yards.

150. The escape time available will depend on a number of factors, including the number of escape routes available, the travel distance to be covered, the nature of the occupants, staff availability and the speed of fire growth.

151. The number and capability of people present will influence the assessment of the escape routes. The existing escape routes must be sufficient to enable the maximum number of people likely to use the premises at any time to safely escape. The outcome of a fire safety risk assessment may necessitate an increase in the capacity of the escape routes or a restriction on the number of people in the premises.

152. In multi-occupied buildings, escape routes within premises should normally be independent of separately occupied premises; people should not have to go through another occupier's premises to escape as the route may be secured or obstructed. Where such independent escape is not possible, then a robust legal agreement may be required to ensure access at all relevant times.

153. Fire escape staircases in all premises, including common staircases in flatted accommodation, should normally be enclosed with fire-resisting materials to form a protected zone(s). This is particularly relevant where the staircase is the only escape route available. For a variety of reasons, such enclosure of common staircases may not always be readily achievable, particularly where there are a number of different owners/occupiers. Where a common staircase cannot be enclosed, consideration should be given to the suitability, or otherwise, of the use to which the premises are put.

154. Providing an appropriate number of stairs, escape routes and exits is fundamental to fire safety. The information which follows in this Chapter contains benchmarks against which existing provision can be compared. Where it is not practical to reduce travel distance or to increase the number of exits, the provision of an automatic life safety sprinkler system may be considered as an alternative (see Chapter 11).

Travel Distance

155. Travel distance may be considered as follows:

• Distance travelled within accommodation to the final exit, protected zone or external escape stair (see Table 2);
• Distance travelled within a flat/maisonette to its main entrance/exit door (see Table 2); or
• Distance travelled from the main entrance/exit door of a flat/maisonette to the final exit, protected zone or external escape stair (see Table 3).

Table 2 Maximum travel distance within flats/maisonettes/small premises related to available directions of travel

Table 3 Maximum travel distance from the entrance door of a flat or maisonette

Inner Rooms

156. An inner room is a room where access to a circulation route can only be achieved by passing through another room (see fig 3). The following conditions should apply:

• An access room should not be of a higher fire risk than an inner room, particularly where the inner room is used as a bedroom. For example, it would be unsuitable for the access room to be a kitchen where the inner room is a bedroom;
• Where an inner room is used to provide sleeping accommodation, a smoke detector(s) capable of providing a suitable warning of fire to persons within the inner room should be provided within the access room; and
• The maximum travel distance from any point in the inner room to the exit from the access room should not exceed 15 m unless there are alternative exits from the access room.

Figure 3 Single direction of escape out of an inner room and through an access room before a choice of escape routes becomes available.

Escape Routes

157. Each storey and room should have a minimum of two escape routes or exits, unless otherwise indicated in the table below:

Table 4 Minimum number of storey exits / escape routes

158. An escape route should give access to a safe area beyond the building:

• Directly;
• By way of a protected zone or unprotected zone;
• By way of an unprotected zone to a protected zone;
• By way of a flat roof or access deck;
• By way of an exit to an external escape stair; or
• In the case of escape from an inner room by way of one other room but not through a place of higher fire risk.

159. An escape route should not normally be by way of a lift.

160. Where any stair, corridor or escape route serves sleeping accommodation it should be constructed of fire-resisting partitions and self-closing fire doors of at least short duration (30 minutes) fire-resistance.

161. In every storey required to have at least two escape stairs such stairs should be independent of each other. Every escape stair should give access directly to a safe area.

162. Where a building or part of a building has only one escape route by way of an escape stair, then any rooms or corridors giving access to the stair should be provided with automatic smoke detection.

163. Each escape stair should be within a protected zone which leads directly to a safe area beyond the building. A protected zone enclosing an escape stair should not enclose any room including a store room or any other ancillary rooms. The enclosing structure of the protected zone should have at least a short duration (30 minutes) fire-resistance; any door in the enclosing structure should be at least an FD 30S self-closing fire door.

164. Where an escape stair also serves a basement storey, the protected zone enclosing the escape stair in the basement storey should be separated from the protected zone containing the escape stair serving the rest of the building, by a wall or screen, with or without a door, at the ground storey floor level. The wall, screen and self-closing fire door where provided, should have a minimum of short duration (30 minutes) fire-resistance.

Escape Across Flat Roofs and Access Decks

165. An escape route across a flat roof or access deck is only acceptable providing the following criteria are met:

• Routes across flat roofs should not normally exceed 7.5 m in height;
• Routes across flat roofs should normally not be for use by members of the public;
• Any escape route across a flat roof or access deck should be unobstructed and normally be flat;
• Routes should be clearly defined and capable of being adequately illuminated across their entire length as appropriate;
• Route should have a slip free surface and be guarded with protective barriers not less than 1.1 m in height along their length including roof edge protection at the point any such route across a flat roof meets an unenclosed external staircase;
• Routes should be constructed as a fire-resisting floor with a minimum of medium duration (60 minute) fire-resistance for a distance of 3 m on either side;
• There should be no unprotected openings such as roof exhausts/ventilators, windows or other openings, from adjacent rooftop structures, within a distance of 2 m on either side;
• Where any wall along the escape route is within 3 m of the route then it should have a minimum of short duration (30 minute) fire-resistance up to a height of at least 1.1 m from the level of the escape route;
• An exit from a flat roof or access deck must lead directly to a place of safety via an enclosed or, alternatively, unenclosed external staircase or by other suitable means; and
• An escape route across a flat roof should be an alternative additional provision to an existing fully compliant protected staircase in any building.

External Stairs

166. External escape stairs may present additional problems to persons evacuating a building in the event of fire because the escape stair will be exposed to the possible effects of inclement weather and people who are unfamiliar with the escape routes can feel less confident using an unenclosed stair high above the ground. If external stairs are used for evacuation, then consideration should be given to weather protection measures and surfaces must be maintained free of any slip hazards. For these reasons, an external escape stair should normally only serve a building where the topmost storey height is not more than 7.5 m.

167. An external escape stair should lead directly to a safe area beyond the premises and be protected against fire from within the building in accordance with the guidance below. However, fire protection need not be provided to an external escape stair with a total rise not more than 1.6 m. External escape stairs should be constructed of non-combustible materials.

168. Every part of an external wall (including a door, window or other opening) not more than 2 m from the external escape stair, should have short duration (30 minutes) fire-resistance. However, this does not apply to a door opening from the top storey to the external escape stair. Fire protection to the wall below an escape stair should be extended to the lowest ground level. Due to the likely smoke dissipation to atmosphere, service openings including ventilation ducts not more than 2 m from the escape stair should be protected by heat activated sealing devices or systems.