5.1This Section gives guidance on the construction and protection of escape routes generally, service installations and other matters associated with the design of escape routes. It applies to all buildings.
It should therefore be read in conjunction with Section 2 (in respect of flats) and in conjunction with Sections 3 and 4 (in respect of other buildings).
Protection of escape routes
Fire resistance of enclosures
5.2Details of fire resistance test criteria and standards of performance, are set out in Appendix A. Generally, a 30-minute standard is sufficient for the protection of means of escape. The exceptions to this are when greater fire resistance is required by the guidance on Requirements B3 or B5, or some other specific instance to meet Requirement B1, in Sections 2 and 3.
5.3All walls, partitions and other enclosures that need to be fire-resisting to meet the provisions in this Approved Document (including roofs that form part of a means of escape), should have the appropriate performance given in Tables A1 and A2 of Appendix A.
5.4Elements protecting a means of escape should meet any limitations on the use of glass (see paragraph 5.7).
5.5Details of fire resistance test criteria and standards of performance, are set out in Appendix B.
5.6All doors that need to be fire-resisting to meet the provisions in this Approved Document should have the appropriate performance given in Table B1 of Appendix B.
Doors should also meet any limitations on the use of glass (see paragraph 5.7).
Fire resistance of glazed elements
5.7Where glazed elements in fire-resisting enclosures and doors are only able to satisfy the relevant performance in terms of integrity, the use of glass is limited. These limitations depend on whether the enclosure forms part of a protected shaft (see Section 8) and the provisions set out in Appendix A, Table A4.
5.8Where the relevant performance can be met in terms of both integrity and insulation, there is no restriction in this Approved Document on the use or amount of glass.
5.9Attention is also drawn to the guidance on the safety of glazing in Approved Document N Glazing – safety in relation to impact, opening and cleaning.
Doors on escape routes
5.10The time taken to negotiate a closed door can be critical in escaping. Doors on escape routes (both within and from the building) should therefore be readily openable, if undue delay is to be avoided. Accordingly the provisions in paragraphs 5.11 to 5.18 should be met.
5.11In general, doors on escape routes (whether or not the doors are fire doors), should either not be fitted with lock, latch or bolt fastenings, or they should only be fitted with simple fastenings that can be readily operated from the side approached by people making an escape. The operation of these fastenings should be readily apparent; without the use of a key and without having to manipulate more than one mechanism. This is not intended to prevent doors being fitted with hardware to allow them to be locked when the rooms are empty. There may also be situations such as hotel bedrooms where locks may be fitted that are operated from the outside by a key and from the inside by a knob or lever, etc.
Where a door on an escape route has to be secured against entry when the building or part of the building is occupied, it should only be fitted with a lock or fastening which is readily operated, without a key, from the side approached by people making their escape. Similarly, where a secure door is operated by a code, combination, swipe or proximity card, biometric data or similar means, it should also be capable of being overridden from the side approached by people making their escape.
Electrically powered locks should return to the unlocked position:
- aon operation of the fire alarm system;
- bon loss of power or system error;
- con activation of a manual door release unit (Type A) to BS EN 54-11:2001 positioned at the door on the side approached by people making their escape. Where the door provides escape in either direction, a unit should be installed on both sides of the door.
5.12In the case of places of assembly, shop and commercial buildings, doors on escape routes from rooms with an occupant capacity of more than 60 should either not be fitted with lock, latch or bolt fastenings, or be fitted with panic fastenings in accordance with BS EN 1125:1997.
In non-residential buildings it may also be appropriate to accept on some final exit doors locks for security that are used only when the building is empty. In these cases the emphasis for the safe use of these locks must be placed on management procedures.
5.13Guidance about door closing and ‘hold open’ devices for fire doors is given in Appendix B.
Direction of opening
5.14 The door of any doorway or exit should, if reasonably practicable, be hung to open in the direction of escape and should always do so if the number of persons that might be expected to use the door at the time of a fire is more than 60.
Notes:Where there is a very high fire risk with potential for rapid fire growth, such as with some industrial activities, doors should open in the direction of escape even where the number of persons does not exceed 60.
Amount of opening and effect on associated escape routes
5.15All doors on escape routes should be hung to open not less than 90 degrees with a swing that is clear of any change of floor level, other than a threshold or single step on the line of the doorway (see paragraph 5.21) and which does not reduce the effective width of any escape route across a landing.
5.16A door that opens towards a corridor or a stairway should be sufficiently recessed to prevent its swing from encroaching on the effective width of the stairway or corridor.
Vision panels in doors
5.17Vision panels are needed where doors on escape routes sub-divide corridors, or where any doors are hung to swing both ways. Note also the provision in Approved Document M Access to and Use of buildings, concerning vision panels in doors across accessible corridors and passageways and the provisions for the safety of glazing in Approved Document N Glazing – safety in relation to impact, opening and cleaning.
5.18Revolving doors, automatic doors and turnstiles can obstruct the passage of persons escaping. Accordingly, they should not be placed across escape routes unless:
- athey are to the required width and are automatic doors and either they:
- iare arranged to fail safely to outward opening from any position of opening; or
- iiare provided with a monitored failsafe system for opening the doors if the mains supply fails; or
- iiithey fail safely to the open position in the event of power failure; or
- bnon-automatic swing doors of the required width are provided immediately adjacent to the revolving or automatic door or turnstile.
Construction of escape stairs
5.19The flights and landings of every escape stair should be constructed of materials of limited combustibility in the following situations:
- aif it is the only stair serving the building, or part of the building, unless the building is of two or three storeys and is in Purpose Group 1(a) or Purpose Group 3;
- bif it is within a basement storey (this does not apply to a private stair in a flat);
- cif it serves any storey having a floor level more than 18m above ground or access level;
- dif it is external, except in the case of a stair that connects the ground floor or paving level with a floor or flat roof not more than 6m above or below ground level. (There is further guidance on external escape stairs in paragraph 5.25); or
- eif it is a firefighting stair (see Section 17).
Notes:In satisfying the above conditions, combustible materials may be added to the horizontal surface of these stairs (except in the case of firefighting stairs).
5.20There is further guidance on the construction of firefighting stairs in Section 17. Dimensional constraints on the design of stairs generally, to meet requirements for safety in use, are given in Approved Document K, Protection from falling, collision and impact.
5.21Single steps may cause falls and should only be used on escape routes where they are prominently marked. A single step on the line of a doorway is acceptable, subject to paragraph 5.32.
Helical stairs, spiral stairs and fixed ladders
5.22Helical stairs, spiral stairs and fixed ladders may form part of an escape route subject to the following restrictions:
- aSingle steps may cause falls and should only be used on escape routes where they are prominently marked. A single step on the line of a doorway is acceptable, subject to paragraph 5.32.
- bfixed ladders should not be used as a means of escape for members of the public and should only be intended for use in circumstances where it is not practical to provide a conventional stair, for example, as access to plant rooms that are not normally occupied.
5.23Guidance on the design of helical and spiral stairs and fixed ladders, from the aspect of safety in use, is given in Approved Document K Protection from falling, collision and impact.
External walls of protected stairways
5.24With some configurations of external wall, a fire in one part of a building could subject the external wall of a protected stairway to heat (for example, where the two are adjacent at an internal angle in the facade as shown in Diagram 24). If the external wall of the protected stairway has little fire resistance, there is a risk that this could prevent the safe use of the stair.
- aa protected stairway projects beyond, or is recessed from, or is in an internal angle of, the adjoining external wall of the building; then
- bthe distance between any unprotected area in the external enclosures to the building and any unprotected area in the enclosure to the stairway should be at least 1800mm (see Diagram 24).
External escape stairs
5.25Where an external escape stair is provided in accordance with paragraph 4.44, it should meet the following provisions:
- aall doors giving access to the stair should be fire-resisting and self-closing, except that a fire-resisting door is not required at the head of any stair leading downwards where there is only one exit from the building onto the top landing;
- bany part of the external envelope of the building within 1800mm of (and 9m vertically below), the flights and landings of an external escape stair should be of fire-resisting construction, except that the 1800mm dimension may be reduced to 1100mm above the top level of the stair if it is not a stair up from a basement to ground level (see Diagram 25);
- cthere is protection by fire-resisting construction for any part of the building (including any doors) within 1800mm of the escape route from the stair to a place of safety, unless there is a choice of routes from the foot of the stair that would enable the people escaping to avoid exposure to the effects of the fire in the adjoining building;
- dany stair more than 6m in vertical extent is protected from the effects of adverse weather conditions. (This should not be taken to imply a full enclosure. Much will depend on the location of the stair and the degree of protection given to the stair by the building itself); and
- eglazing in areas of fire-resisting construction mentioned above should also be fire-resisting (integrity but not insulation) and fixed shut.
Headroom in escape routes
5.26All escape routes should have a clear headroom of not less than 2m and there should be no projection below this height (except for door frames).
Floors of escape routes
5.27The floorings of all escape routes (including the treads of steps and surfaces of ramps and landings) should be chosen to minimise their slipperiness when wet.
Ramps and sloping floors
5.28Where a ramp forms part of an escape route it should meet the provisions in Approved Document M Access to and Use of buildings. Any sloping floor or tier should be constructed with a pitch of not more than 35deg to the horizontal.
5.29Further guidance on the design of ramps and associated landings and on aisles and gangways in places where there is fixed seating, from the aspect of safety in use, is given in Approved Document K Protection from falling, collision and impact and in Approved Document M Access to and Use of buildings . The design of means of escape in places with fixed seating is dealt with in Section 3 by reference to BS 5588-6:1991.
5.30Final exits need to be dimensioned and sited to facilitate the evacuation of persons out of and away from the building. Accordingly, they should be not less in width than the minimum width required for the escape route(s) they serve and should also meet the conditions in paragraphs 5.31 to 5.34.
5.31 Final exits should be sited to ensure rapid dispersal of persons from the vicinity of the building so that they are no longer in danger from fire and smoke. Direct access to a street, passageway, walkway or open space should be available. The route clear of the building should be well defined and, if necessary, have suitable guarding.
5.32Final exits should not present an obstacle to wheelchair users and other people with disabilities. Where a final exit is accessed without the need to first traverse steps then a level threshold and, where necessary, a ramp should be provided.
5.33Final exits need to be apparent to persons who may need to use them. This is particularly important where the exit opens off a stair that continues down, or up, beyond the level of the final exit.
5.34Final exits should be sited so that they are clear of any risk from fire or smoke in a basement (such as the outlets to basement smoke vents, see Section 18), or from openings to transformer chambers, refuse chambers, boiler rooms and similar risks.
Escape routes over flat roofs
5.35Where an escape route over a flat roof is provided in accordance with paragraph 2.31 or 3.31, it should meet the following provisions:
- athe roof should be part of the same building from which escape is being made;
- bthe route across the roof should lead to a storey exit or external escape route;
- cthe part of the roof forming the escape route and its supporting structure, together with any opening within 3m of the escape route, should be fire-resisting (see Appendix A Table A1); and
- dthe route should be adequately defined and guarded by walls and/or protective barriers which meet the provisions in Approved Document K, Protection from falling, collision and impact.
Lighting of escape routes
5.36All escape routes should have adequate artificial lighting. Routes and areas listed in Table 9 should also have escape lighting which illuminates the route if the main supply fails. Lighting to escape stairs should be on a separate circuit from that supplying any other part of the escape route. Standards for the installation of a system of escape lighting are given in BS 5266-1:2005.
5.37Except within a flat, every escape route (other than those in ordinary use) should be distinctively and conspicuously marked by emergency exit sign(s) of adequate size complying with the Health and Safety (Safety signs and signals) Regulations 1996. In general, signs containing symbols or pictograms which conform to BS 5499-1:2002, satisfy these regulations. In some buildings additional signs may be needed to meet requirements under other legislation.
Suitable signs should also be provided for refuges (see paragraph 4.10).
Notes:Advice on fire safety signs, including emergency escape signs, is given in an HSE publication: Safety Signs and Signals: Guidance on Regulations.
Protected power circuits
5.38Where it is critical for electrical circuits to be able to continue to function during a fire, protected circuits are needed. The potential for damage to cables forming protected circuits should be limited by the use of sufficiently robust cables, careful selection of cable routes and/or by the provision of physical protection in areas where cables may be susceptible to damage. Methods of cable support should generally be non-combustible and such that circuit integrity will not be reduced below that afforded by the cable.
A protected circuit for operation of equipment in the event of fire should consist of cable meeting at least the requirements for PH 30 classification when tested in accordance with BS EN 50200:2006 (incorporating Appendix E), or an equivalent standard. It should follow a route selected to pass only through parts of the building in which the fire risk is negligible and should be separate from any circuit provided for another purpose.
In large or complex buildings there may be fire protection systems that need to operate for an extended period during a fire. Further guidance on the selection of cables for such systems is given in BS 5839-1, BS 5266-1 and BS 7346-6.
5.39In general it is not appropriate to use lifts when there is a fire in the building because there is always the danger of people being trapped in a lift that has become immobilised as a result of the fire. However, in some circumstances a lift may be provided as part of a management plan for evacuating people. In such cases the lift installation may need to be appropriately sited and protected and may need to contain a number of safety features that are intended to ensure that the lift remains usable for evacuation purposes during the fire. Guidance on the design and use of evacuation lifts is given in BS 5588-8:1999.
Where a firefighting lift has been provided to satisfy requirement B5, this can be utilised as part of a management plan for evacuating disabled people. Any such plan should include a contingency for when the Fire and Rescue Service arrive.
Fire protection of lift installations
5.40Because lifts connect floors, there is the possibility that they may prejudice escape routes. To safeguard against this, the conditions in paragraphs 5.41 to 5.45 should be met.
5.41Lifts, such as wall-climber or feature lift which rise within a large volume, such as a mall or atrium, and do not have a conventional well, may be at risk if they run through a smoke reservoir. In which case, care is needed to maintain the integrity of the smoke reservoir and protect the occupants of the lift.
5.42Lift wells should be either:
- acontained within the enclosures of a protected stairway; or
- benclosed throughout their height with fire-resisting construction if they are sited so as to prejudice the means of escape.
A lift well connecting different compartments should form a protected shaft (see Section 8).
In buildings designed for phased or progressive horizontal evacuation, where the lift well is not contained within the enclosures of a protected stairway, the lift entrance should be separated from the floor area on every storey by a protected lobby.
5.43In basements and enclosed (non open-sided) car parks the lift should be approached only by a protected lobby (or protected corridor), unless it is within the enclosure of a protected stairway.
This is also the case in any storey that contains high fire risk areas, if the lift also delivers directly into corridors serving sleeping accommodation. Examples of fire risk areas in this context are kitchens, communal lounges and stores.
5.44A lift shaft should not be continued down to serve any basement storey if it is:
- ain a building (or part of a building) served by only one escape stair and smoke from a basement fire would be able to prejudice the escape routes in the upper storeys; or
- bwithin the enclosure to an escape stair which is terminated at ground level.
5.45Lift machine rooms should be sited over the lift well whenever possible. If the lift well is within a protected stairway which is the only stairway serving the building (or part of the building), then if the machine room cannot be sited above the lift well, it should be located outside the stairway (to avoid smoke spread from a fire in the machine room).
Mechanical ventilation and air-conditioning systems
5.46Any system of mechanical ventilation should be designed to ensure that, in a fire, the ductwork does not assist in transferring fire and smoke through the building and put at risk the protected means of escape from the accommodation areas. Any exhaust points should be sited so as not to further jeopardize the building, i.e. away from final exits, combustible building cladding or roofing materials and openings into the building.
5.47Ventilation ducts supplying or extracting air directly to or from a protected escape route, should not also serve other areas. A separate ventilation system should be provided for each protected stairway. Guidance on ventilation systems that circulate air only within an individual flat is given in paragraph 2.18.
Where the ductwork system serves more than one part of a sub-divided (see paragraph 3.26) escape route, a fire damper should be provided where ductwork enters each section of the escape route operated by a smoke detector or suitable fire detection system (see also Section 10). The fire dampers should close when smoke is detected.
5.48Ducts passing through the enclosure of a protected escape route should be fire-resisting, i.e. the ductwork should be constructed in accordance with Method 2 or Method 3, (see paragraph 10.9).
Notes:Fire dampers activated only by fusible links are not suitable for protecting escape routes. However an ES classified fire and smoke damper which is activated by a suitable fire detection system may be used. See paragraph 10.15.
5.49In the case of a system which recirculates air, smoke detectors should be fitted in the extract ductwork before the point of separation of the recirculated air and the air to be discharged to the open air and before any filters or other air cleaning equipment. Such detector(s) should:
- acause the system to immediately shut down; or
- bswitch the ventilation system from recirculating mode to extraction to open air, so as to divert the any smoke to the outside of the building.
5.50Non-domestic kitchens, car parks and plant rooms should have separate and independent extraction systems and the extracted air should not be recirculated.
5.51Guidance on the use of mechanical ventilation in a place of assembly is given in BS 5588-6:1991.
5.52Where a pressure differential system is installed, ventilation and air-conditioning systems in the building should be compatible with it when operating under fire conditions.
5.53Further guidance on the design and installation of mechanical ventilation and air conditioning plant is given in BS 5720:1979. Guidance on the provision of smoke detectors in ventilation ductwork is given in BS 5839-1:2002.
Notes:Paragraphs 8.41 and 10.9 also deal with ventilation and air-conditioning ducts.
Refuse chutes and storage
5.54Refuse storage chambers, refuse chutes and refuse hoppers should be sited and constructed in accordance with BS 5906 Code of practice for storage and on-site treatment of solid waste from buildings.
5.55Refuse chutes and rooms provided for the storage of refuse should:
- abe separated from other parts of the building by fire-resisting construction; and
- bnot be located within protected stairways or protected lobbies.
5.56Rooms containing refuse chutes, or provided for the storage of refuse, should be approached either directly from the open air or by way of a protected lobby provided with not less than 0.2m2 of permanent ventilation.
5.57Access to refuse storage chambers should not be sited adjacent to escape routes or final exits, or near to windows of flats.
Shop store rooms
5.58Fully enclosed walk-in store rooms in shops (unless provided with an automatic fire detection and alarm system or fitted with sprinklers) should be separated from retail areas with fire-resisting construction (see Appendix A, Table A1), if they are sited so as to prejudice the means of escape.