Width of Escape Routes and Exits (2)
22.214.171.124 Protected corridors - A corridor which serves as part of the means of escape in any of the following circumstances should be a protected corridor (see Table A1, Appendix A):
(a) every corridor serving sleeping accommodation within Residential (Institutional) or other Residential buildings (Purpose Groups 2(a) or 2(b));
(b) every dead-end corridor;
(c) any corridor common to two or more different occupancies (see also par. 126.96.36.199).
188.8.131.52 Enclosure of corridors that are not protected corridors - The enclosures to all corridors used as means of escape (which are not protected corridors) should be carried up to the underside
of the structural floor above (or to a suspended ceiling) and all openings in the corridor enclosures should be fitted with doors.
184.108.40.206 Sub-division of corridors - If a corridor provides access to alternative escape routes, there is a risk that smoke will spread along it and make both routes impassable before all occupants
have escaped. To avoid this, every corridor connecting two or more storey exits where the distance between storey exits exceeds 12 m should be sub-divided by self-closing fire doors (and any necessary associated screens) so that:
(a) no length of undivided corridor is common to two storey exits; and
(b) the fire door(s) are positioned to effectively safeguard the route from smoke, having regard to the layout of the corridor and to any adjacent fire risks.
220.127.116.11 Separation of dead-ends - If a dead-end portion of a corridor provides access to a point from which alternative escape routes are available, there is a risk that smoke from a fire could
make both routes impassable before the occupants in the dead-end have escaped. To avoid this, unless the escape stairway(s) and corridors are protected by a pressurization system complying with BS 5588: Part 4: 1978; every dead end corridor exceeding
4.5 m in length should be separated by self-closing fire doors (together with any necessary associated screens) from any part of the corridor which:
(a) provides two directions of escape (Diagram 5(a)); or
(b) continues past one storey exit to another (Diagram 5(b)).
1.2.6 External Escape Routes
18.104.22.168 External escape stairway - If more than one escape route is required from a storey, or part of a building, one of those routes may be by way of an external escape stairway provided that:
(a) in the case of an assembly and recreation building, the route is not intended for use by members of the public; or
(b) in the case of a Residential (Institutional) building, the route serves only office or residential staff accommodation.
In the case of an existing building, the use of an external escape stairway as an alternative means of escape may be acceptable, where there is no practicable alternative solution. Where the building is used for assembly and recreation, the number of
persons likely to use the stairway should not exceed 150.
External escape stairways should comply with the requirements set out in par. 1.3.9.
22.214.171.124 Escape over flat roofs - If more than one escape route is required from a storey, or part of a building, one of those routes may be by way of a flat roof, provided that:
(a) the route does not serve a Residential (Institutional) building, or a part of a building intended for use by members of the public;
(b) the roof is part of the same building from which escape is being made, or if it is part of another building, there is a legal agreement between the parties concerned which includes a right of entry into that building;
(c) the route across the roof leads to a storey exit;
(d) the part of the roof forming the escape route and its supporting structure, together with any opening within 3 m of the escape route, is fire- resisting; and
(e) the route is adequately defined and guarded by walls and/or protective barriers which meet the provisions in Technical Guidance Document K.
In the case of any existing building, an escape route by way of a flat roof which complies with (b) to (e) above may be acceptable as an alternative means of escape, where combined with an external escape stairway as outlined at 126.96.36.199 above. Where the
building is used for assembly and recreation the numbers of persons likely to use such an escape route should not exceed 150.
The provisions of this paragraph do not prohibit an escape route by way of an external podium which gives direct access to a place of safety and where the roof is constructed of non-combustible construction having a fire resistance of at least 60 minutes.
Diagram 5 Dead end corridors (Par. 188.8.131.52) Part B