Section 3: Means of escape – flats
Introduction
3.1 Separate guidance applies to means of escape within the flat and within the common parts of the building that lead to a place of safety. Flats at ground level are treated similarly to dwellinghouses. With increasing height, more complex provisions are needed.
3.2 The provisions in this section make the following assumptions.
a. Any fire is likely to be in a flat.
b. There is no reliance on external rescue.
c. Simultaneous evacuation of all flats is unlikely to be necessary due to compartmentation.
d. Fires in common parts of the building should not spread beyond the fabric in the immediate vicinity. In some cases, however, communal facilities exist that require additional measures to be taken.
3.3 Provisions are recommended to support a stay put evacuation strategy for blocks of flats. It is based on the principle that a fire is contained in the flat of origin and common escape routes are maintained relatively free from smoke and heat. It allows occupants, some of whom may require assistance to escape in the event of a fire, in other flats that are not affected to remain.
Sufficient protection to common means of escape is necessary to allow occupants to escape should they choose to do so or are instructed/aided to by the fire service. A higher standard of protection is therefore needed to ensure common escape routes remain available for a longer period than is provided in other buildings.
3.4 Paragraphs 3.6 to 3.23 deal with the means of escape within each flat. Paragraphs 3.25 to 3.89 deal with the means of escape in common areas of the building (including mixed use buildings in paragraphs 3.76 and 3.77). Guidance for live/work units is given in paragraph 3.24.
General provisions
Mixed use buildings
3.5 In mixed use buildings, separate means of escape should be provided from any storeys or parts of storeys used for the ‘residential’ or ‘assembly and recreation’ purpose groups (purpose groups 1, 2 and 5), other than in the case of certain small buildings or buildings in which the residential accommodation is ancillary (see paragraphs 3.76 and 3.77)
Emergency escape windows and external doors
3.6 Windows or external doors providing emergency escape should comply with all of the following.
a. Windows should have an unobstructed openable area that complies with all of the following.
i. A minimum area of 0.33m2.
ii. A minimum height of 450mm and a minimum width of 450mm (the route through the window may be at an angle rather than straight through).
iii. The bottom of the openable area is a maximum of 1100mm above the floor.
b. People escaping should be able to reach a place free from danger from fire.
c. Locks (with or without removable keys) and opening stays (with child-resistant release catches) may be fitted to escape windows.
d. Windows should be capable of remaining open without being held.
Inner rooms
3.7 An inner room is permitted when it is one of the following.
a. A kitchen.
b. A laundry or utility room.
c. A dressing room.
d. A bathroom, WC or shower room.
e. Any room on a storey that is a maximum of 4.5m above ground level which is provided with an emergency escape window as described in paragraph 3.6.
f. A gallery that complies with paragraph 3.13.
3.8 A room accessed only via an inner room (an inner inner room) is acceptable when all of the following apply.
a. It complies with paragraph 3.7.
b. The access rooms each have a smoke alarm (see Section 1).
c. None of the access rooms is a kitchen.
Basements
3.9 Basement storeys containing habitable rooms should have one of the following.
a. An emergency escape window or external door providing escape from the basement (see paragraph 3.6).
b. A protected stairway (minimum REI 30) leading from the basement to a final exit.
Balconies and flat roofs
3.10 Where a flat roof forms part of a means of escape, it should comply with all of the following.
a. It should be part of the same building from which escape is being made.
b. The route across the roof should lead to a storey exit or external escape route.
c. The part of the roof (including its supporting structure) forming the escape route, and any opening within 3m of the escape route, should be of fire resisting construction (minimum REI 30).
3.11 A balcony or flat roof intended to form part of an escape route should be provided with guarding etc. in accordance with Approved Document K.
3.12 For flats more than 4.5m above ground level, a balcony outside an alternative exit should be a common balcony meeting the conditions described in paragraph 3.22.
Galleries
3.13 A gallery should comply with one of the following.
a. It should be provided with an alternative exit.
b. It should be provided with an emergency escape window, as described in paragraph 3.6, where the gallery floor is a maximum of 4.5m above ground level.
c. It should meet the conditions shown in Diagram 3.1.
Diagram 3.1 Gallery floors with no alternative exit
Flats with upper storeys a maximum of 4.5m above ground level
3.14 The internal arrangement of single storey or multi-storey flats should comply with paragraphs 3.15 to 3.17. Alternatively, the guidance in paragraphs 3.18 to 3.22 may be followed.
A flat accessed via the common parts of the building should also comply with the provisions for small single stair buildings in paragraph 3.28 and Diagram 3.9. A protected entrance hall may be required as a result.
Escape from the ground storey
3.15 All habitable rooms (excluding kitchens) should have either of the following.
a. An opening directly onto a hall leading to a final exit.
b. An emergency escape window or door, as described in paragraph 3.6.
Escape from upper storeys a maximum of 4.5m above ground level
3.16 All habitable rooms (excluding kitchens) should have either of the following.
a. An emergency escape window or external door, as described in paragraph 3.6.
b. In multi-storey flats, direct access to a protected internal stairway (minimum REI 30) leading to an exit from the flat.
3.17 Two rooms may be served by a single escape window. A door between rooms should provide access to the escape window without passing through the stair enclosure. Both rooms should have their own access to the internal stair.
Flats with storeys more than 4.5m above ground level
Internal planning of single storey flats
3.18 One of the following approaches should be adopted, observing the inner room restrictions described in paragraphs 3.7 and 3.8.
a. Provide a protected entrance hall (minimum REI 30) serving all habitable rooms that meets the conditions shown in Diagram 3.2.
b. Plan the flat to meet the conditions shown in Diagram 3.3, so that both of the following apply.
i. The travel distance from the flat entrance door to any point in any habitable room is a maximum of 9m.
ii. Cooking facilities are remote from the main entrance door and do not impede the escape route from anywhere in the flat.
c. Provide an alternative exit from the flat complying with paragraph 3.22.
Diagram 3.2 Flat where all habitable rooms have direct access to an entrance hall
Diagram 3.3 Flat with restricted travel distance from furthest point to entrance
Flats with an alternative exit
3.19 Where access from any habitable room to the entrance hall or flat entrance is impossible without passing through another room, all of the following conditions should be met (Diagram 3.4).
a. Bedrooms should be separated from living accommodation by fire resisting construction (minimum REI 30) and fire doorsets (minimum E 20).
b. The alternative exit should be in the part of the flat that contains the bedrooms.
Diagram 3.4 Flat with an alternative exit, but where all habitable rooms have no direct access to an entrance hall
Internal planning of multi storey flats
3.20 A multi-storey flat with an independent external entrance at ground level is similar to a dwellinghouse and means of escape should be planned on the basis of Section 2, depending on the height of the top storey above ground level.
3.21 When multi-storey flats do not have their own external entrance at ground level, adopt one of the following approaches.
a. Approach 1 – provide at least one alternative exit from each habitable room that is not on the entrance storey of the flat (Diagram 3.5 and paragraph 3.22).
b. Approach 2 – provide at least one alternative exit from each storey that is not the entrance storey of the flat. All habitable rooms should have direct access to a protected landing (Diagram 3.6 and paragraph 3.22).
c. Approach 3 – provide a protected stairway plus a sprinkler system in accordance with Appendix E and provide smoke alarms in accordance with BS 5839-6.
d. Approach 4 – if the vertical distance between the entrance storey of the flat and any of the storeys above or below does not exceed 7.5m, provide all of the following.
i. A protected stairway.
ii. Additional smoke alarms in all habitable rooms.
iii. A heat alarm in any kitchen.
Diagram 3.5 Multi-storey flat with alternative exits from each habitable room, except at entrance level
Diagram 3.6 Multi-storey flat with protected entrance hall and landing
Alternative exits
3.22 Any alternative exit from a flat should comply with all of the following.
a. It should be remote from the main entrance door to the flat.
b. It should lead to a final exit, via a common stair if necessary, through one of the following.
i. A door to an access corridor, access lobby or common balcony.
ii. An internal private stair leading to an access corridor, access lobby or common balcony at another level.
iii. A door to a common stair.
iv. A door to an external stair.
v. A door to an escape route over a flat roof.
Any access route leading to a final exit or common stair should comply with the provisions for means of escape in the common parts of a flat (see paragraph 3.25).
Air circulation systems in flats with a protected stairway or entrance hall enclosure
3.23 For systems circulating air only within an individual flat, take all of the following precautions.
a. Transfer grilles should not be fitted in any wall, door, floor or ceiling of the enclosure.
b. Any duct passing through the enclosure should be rigid steel. Joints between the ductwork and enclosure should be fire-stopped.
c. Ventilation ducts serving the enclosure should not serve any other areas.
d. Any system of mechanical ventilation which recirculates air and which serves both the stair and other areas should be designed to shut down on the detection of smoke within the system.
e. For ducted warm air heating systems, a room thermostat should be sited in the living room. It should be mounted at a height between 1370mm and 1830mm above the floor. The maximum setting should be 27°C.
NOTE: Ventilation ducts passing through compartment walls should comply with the guidance in Section 9.
Live/work units
3.24 For flats serving as a workplace for both occupants and people who do not live on the premises, provide both of the following.
a. A maximum travel distance of 18m between any part of the working area and either of the following.
i. The flat entrance door.
ii. An alternative means of escape that is not a window.
If the travel distance is over 18m, the assumptions in paragraph 3.2 may not be valid. The design should be considered on a case-by-case basis.
b. Escape lighting to windowless accommodation in accordance with BS 5266-1.
Means of escape in the common parts of flats
3.25 The following paragraphs deal with means of escape from the entrance doors of flats to a final exit. They do not apply to flats with a top storey that is a maximum of 4.5m above ground level (designed in accordance with paragraphs 3.16 and 3.17).
Reference should also be made to the following.
a. Requirement B3 regarding compartment walls and protected shafts.
b. Requirement B5 regarding access for the fire and rescue service.
Number of escape routes
3.26 A person escaping through the common area, if confronted by the effects of a fire in another flat, should be able to turn away from it and make a safe escape via an alternative route.
3.27 From the flat entrance door, a single escape route is acceptable in either of the following cases.
a. The flat is on a storey served by a single common stair and both of the following apply.
i. Every flat is separated from the common stair by a protected lobby or common protected corridor (see Diagram 3.7).
ii. The maximum travel distance in Table 3.1, for escape in one direction only, is not exceeded.
b. The flat is in a dead end of a common corridor served by two (or more) common stairs and the maximum travel distance given in Table 3.1, for escape in one direction only, is not exceeded (Diagram 3.8).
Table 3.1 Limitations on travel distance in common areas of blocks of flats
Diagram 3.7 Flats served by one common stair
Diagram 3.8 Flats served by more than one common stair
Small single stair buildings
3.28 For some low rise buildings, the provisions in paragraphs 3.26 and 3.27 may be modified and the use of a single stair, protected in accordance with Diagram 3.9, may be permitted where all of the following apply.
a. The top storey of the building is a maximum of 11m above ground level.
b. No more than three storeys are above the ground storey.
c. The stair does not connect to a covered car park, unless the car park is open sided (as defined in Section 11 of Approved Document B Volume 2).
d. The stair does not serve offices, stores or other ancillary accommodation. If it does, they should be separated from the stair by a protected lobby or protected corridor (minimum REI 30) with a minimum 0.4m2 of permanent ventilation, or be protected from the ingress of smoke by a mechanical smoke control system.
NOTE: For refuse chutes and storage see paragraphs 3.55 to 3.58.
e. Either of the following is provided for the fire and rescue service.
i. A high-level openable vent with a free area of at least 1m2 at each storey.
ii. A single openable vent with a free area of at least 1m2 at the head of the stair, operable remotely at the fire and rescue service access level.
Diagram 3.9 Common escape route in small single stair building
Flats with balcony or deck access
3.29 Paragraph 3.27 may be modified using the guidance in clause 7.3 of BS 9991.
Escape routes over flat roofs
3.30 Where a storey or part of a building has multiple escape routes available, one may be over a flat roof that complies with all of the following.
a. It should be part of the same building from which escape is being made.
b. The route across the roof should lead to a storey exit or external escape route.
c. The part of the roof (including its supporting structure) forming the escape route, and any opening within 3m of the escape route, should be of fire resisting construction (minimum REI 30).
d. The route should be clearly defined and guarded by walls and/or protective barriers to protect against falling.
Common escape routes
3.31 The following paragraphs deal with means of escape from the entrance doors of flats to a final exit.
3.32 Escape route travel distances should comply with Table 3.1.
3.33 An escape route should not pass through one stair enclosure to reach another. It may pass through a protected lobby (minimum REI 30) of one stair to reach another.
3.34 Common corridors should be protected corridors. The wall between each flat and the corridor should be a compartment wall (minimum REI 30 where the top storey is up to 5m above ground level, otherwise REI 60).
3.35 Divide a common corridor connecting two or more storey exits with a fire doorset fitted with a self-closing device (minimum E 30 Sa). See Diagram 3.8. Associated screens should be fire resisting. Site doors so that smoke does not affect access to more than one stair.
3.36 A fire doorset (minimum E 30 Sa) fitted with a self-closing device (and fire resisting screen, where required) should separate the dead-end portion of a common corridor from the rest of the corridor (Diagrams 3.7a, 3.8b and 3.8c).
3.37 Ancillary accommodation should not be located in, or entered from, a protected lobby or protected corridor forming the only common escape route on that storey.
Headroom in common escape routes
3.38 Escape routes should have a minimum clear headroom of 2m. The only projections allowed below this height are door frames.
Flooring of common escape routes
3.39 Escape route floor finishes should minimise their slipperiness when wet. Finishes include the treads of steps and surfaces of ramps and landings.
Ramps and sloping floors
**3.40 A ramp forming part of an escape route should meet the provisions in Approved Document M. Any sloping floor or tier should have a pitch of not more than 35 degrees to the horizontal.
Lighting of common escape routes
3.41 All escape routes should have adequate artificial lighting. If the mains electricity power supply fails, escape lighting should illuminate the route (including external escape routes).
3.42 In addition, escape lighting should be provided to all of the following.
a. Toilet accommodation with a minimum floor area of 8m2.
b. Electricity and generator rooms.
c. Switch room/battery room for emergency lighting system.
d. Emergency control rooms.
3.43 Escape stair lighting should be on a separate circuit from the electricity supply to any other part of the escape route.
3.44 Escape lighting should conform to BS 5266-1.
Exit signs on common escape routes
3.45 Every doorway or other exit providing access to a means of escape, other than exits in ordinary use (e.g. main entrances), should be distinctively and conspicuously marked by an exit sign in accordance with BS ISO 3864-1 and BS 5499-4. For this reason, blocks of flats with a single stair in regular use would not usually require any fire exit signage.
Advice on fire safety signs, including emergency escape signs, is given in the HSE publication Safety Signs and Signals: Guidance on Regulations.
Some buildings may require additional signs to comply with other legislation.
Protected power circuits
3.46 To limit potential damage to cables in protected circuits, all of the following should apply.
a. Cables should be sufficiently robust.
b. Cable routes should be carefully selected and/or physically protected in areas where cables may be exposed to damage.
c. Methods of cable support should be class A1 rated and offer at least the same integrity as the cable. They should maintain circuit integrity and hold cables in place when exposed to fire.
3.47 A protected circuit to operate equipment during a fire should achieve all of the following.
a. Cables should achieve PH 30 classification when tested in accordance with BS EN 50200
(incorporating Annex E) or an equivalent standard.
b. It should only pass through parts of the building in which the fire risk is negligible.
c. It should be separate from any circuit provided for another purpose.
3.48 Guidance on cables for large and complex buildings is given in BS 5839-1, BS 5266-1 and BS 8519.
Smoke control in common escape routes
3.49 Despite the provisions described, it is probable that some smoke will get into the common corridor or lobby from a fire in a flat.
There should therefore be some means of ventilating the common corridors/lobbies to control smoke and so protect the common stairs. This means of ventilation offers additional protection to that provided by the fire doors to the stair, as well as some protection to the corridors/lobbies.
Ventilation can be natural (paragraphs 3.50 to 3.53) or mechanical (paragraph 3.54).
Smoke control of common escape routes by natural smoke ventilation
3.50 Except in buildings that comply with Diagram 3.9, the corridor or lobby next to each stair should have a smoke vent. The location of the vent should comply with both of the following.
a. Be as high as practicable.
b. Be positioned so the top edge is at least as high as the top of the door to the stair.
3.51 Smoke vents should comply with one of the following.
a. They should be located on an external wall with minimum free area of 1.5m2.
b. They should discharge into a vertical smoke shaft, closed at the base, that meets all of the following criteria.
i. The shaft should conform to the following conditions.
• Have a minimum cross-sectional area of 1.5m2 (minimum dimension 0.85m in any direction).
• Open at roof level, minimum 0.5m above any surrounding structures within 2m of it horizontally.
• Extend a minimum of 2.5m above the ceiling of the highest storey served by the shaft.
ii. The free area of all the following vents should be a minimum of 1m2 in the following places.
• From the corridor or lobby into the shaft.
• At the opening at the head of the shaft.
• At all internal locations within the shaft (e.g. safety grilles).
iii. The smoke shaft should be constructed from a class A1 material. All vents should either be a fire doorset (see Appendix C, Table C1, item 2.e for minimum fire resistance) or fitted with a smoke control damper achieving the same period of fire resistance and designed to operate as described below. The shaft should be vertical from base to head, with a maximum of 4m at a maximum inclined angle of 30 degrees.
iv. If smoke is detected in the common corridor or lobby, both of the following should occur.
• Simultaneous opening of vents on the storey where the fire is located, at the top of the smoke shaft and to the stair.
• Vents from the corridors or lobbies on all other storeys should remain closed, even if smoke is subsequently detected on storeys other than where the fire is located.
3.52 A vent to the outside with a minimum free area of 1m2 should be provided from the top storey of the stair.
3.53 In single stair buildings, smoke vents on the storey where the fire is initiated, and the vent at the head of the stair, should be activated by smoke detectors in the common parts.
In buildings with more than one stair, smoke vents may be activated manually. The control system should open the vent at the head of the stair before, or at the same time as, the vent on the storey where the fire is located. Smoke detection is not required for ventilation purposes in this instance.
Smoke control of common escape routes by mechanical ventilation
3.54 Guidance on the design of smoke control systems that use pressure differentials is available in BS EN 12101-6.
Refuse chutes and storage
3.55 Refuse storage chambers, refuse chutes and refuse hoppers should be sited and constructed in accordance with BS 5906.
3.56 Refuse chutes and rooms for storing refuse should meet both of the following conditions.
a. Be separated from other parts of the building by fire resisting construction (minimum REI 30 in buildings with a top storey up to 5m above ground level; otherwise REI 60).
b. Not be situated within a protected stairway or protected lobby.
3.57 The approach to rooms containing refuse chutes or for storing refuse should comply with one of the following conditions.
a. Be directly from the open air.
b. Be through a protected lobby with a minimum of 0.2m2 of permanent ventilation.
3.58 Access openings to refuse storage chambers should not be sited in the following areas.
a. Next to escape routes or final exits.
b. Near the windows of flats.
Common stairs
Number of common stairs
3.59 A building should provide access to more than one common stair if it does not meet the criteria for a single common stair (see paragraph 3.26 and 3.27).
Width of common stairs
3.60 A stair of acceptable width for everyday use will be sufficient for escape purposes. If it is also a firefighting stair, it should be at least 1100mm wide. The width is the clear width between the walls or balustrades. Any handrails and strings intruding into that width by a maximum of 100mm on each side may be ignored.
Protection of common stairs
3.61 Section 7 provides guidance on avoiding the spread of fire between storeys. For a stair that is also a firefighting stair, guidance in Section 15 should be followed.
Enclosure of common stairs
3.62 Every common stair should be a protected stairway, within a fire resisting enclosure (minimum REI 30).
External walls adjacent to protected stairways
3.63 With 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 façade, as shown in Diagram 3.10).
3.64 If a protected stairway projects beyond, is recessed from or is in an internal angle of the adjoining external wall of the building, then the minimum distance between an unprotected area of the building enclosure and an unprotected area of the stair enclosure should be 1800mm.
Diagram 3.10 External protection to protected stairways
External escape stairs
3.65 Flats may be served by an external stair if the provisions in paragraphs 3.66 to 3.69 are followed.
3.66 Where a storey (or part of a building) is served by a single access stair, that stair may be external provided both of the following conditions are met.
a. The stair serves a floor not more than 6m above the ground level.
b. The stair meets the provisions in paragraph 3.62.
3.67 Where more than one escape route is available from a storey (or part of a building), then some of the escape routes from that storey or part of the building may be by way of an external stair provided all of the following conditions are met:
a. There is a at least one internal escape stair from every part of each storey (excluding plant areas).
b. The stair serves a floor not more than 6m above either the ground level or a roof podium which is itself served by an independent protected stairway.
c. The stair meets the provisions in paragraph 3.68.
Diagram 3.11 Fire resistance of areas near to external stairs
3.68 Any external escape stair should meet all of the following conditions (Diagram 3.11).
a. Doors to the stair should be fire resisting (minimum E 30) and be fitted with a self-closing device, except for a single exit door from the building to the top landing of a downward- leading external stair, provided it is the only door onto the landing.
b. Fire resisting construction (minimum RE 30) is required for the building envelope within the following zones, measured from the flights and landings of the external stair.
i. 1800mm above and horizontally.
ii. 9m vertically below.
iii. 1100mm above the top landing of the stair (except where the stair leads from basement to ground level).
c. Fire resisting construction (minimum RE 30) should be provided for any part of the building (including doors) within 1800mm of the escape route from the foot of the stair to a place of safety. This does not apply if there are alternative escape routes from the foot of the external escape stair.
d. Glazing in areas of fire resisting construction should be fixed shut and fire resisting (in terms of integrity but not insulation) (minimum E 30).
e. Stairs more than 6m in height above ground level (e.g. where they are provided above a podium) should be protected from adverse weather. Protection should prevent the build-up of snow or ice but does not require full enclosure.
3.69 Access to an external escape stair may be via a flat roof, provided the flat roof meets the requirements of paragraph 3.30.
Separation of adjoining protected stairways
3.70 The construction separating two adjacent protected stairways (or exit passageways leading to different final exits) should be imperforate.
Basement stairs
3.71 If a building does not meet the criteria of paragraph 3.28, an escape stair forming part of the only escape route from an upper storey should not continue down to serve a basement storey. The basement storey should be served by a separate escape stair.
3.72 Where multiple escape stairs serve the upper storeys, only one needs to end at ground level. Other stairs may connect with the basement storeys if there is a protected lobby or a protected corridor between the stairs and accommodation at each basement level.
Stairs serving ancillary accommodation
3.73 Except in buildings described in paragraph 3.28, common stairs forming part of the only escape route from a flat should not serve any of the following.
a. Covered car park.
b. Boiler room.
c. Fuel storage space.
d. Other ancillary accommodation of similar fire risk.
3.74 Where a common stair is not part of the only escape route from a flat, it may also serve ancillary accommodation from which it is separated by a protected lobby or protected corridor (minimum REI 30).
3.75 Where a stair serves an enclosed car park or place of special fire hazard, the lobby or corridor should have a minimum 0.4m2 of permanent ventilation or be protected from the ingress of smoke by a mechanical smoke control system.
NOTE: For refuse chutes and storage see paragraphs 3.55 to 3.58.
Flats in mixed use buildings
3.76 In buildings with a maximum of three storeys above the ground storey, stairs may serve both flats and other occupancies, provided that the stairs are separated from each occupancy by protected lobbies (minimum REI 30) at each storey.
3.77 In buildings with more than three storeys above the ground storey, stairs may serve the flats and other occupancies if all of the following apply.
a. The flat is ancillary to the main use of the building.
b. The flat has an independent alternative escape route.
c. The stair is separated from occupancies on lower storeys by a protected lobby (minimum REI 30) at each of those storeys.
d. The stair enclosure has at least the same standard of fire resistance as the structural elements of the building (see Appendix B, Table B4); if the stair is a firefighting stair, it should comply with the provisions in Section 15 (see also paragraph 3.60).
e. Any automatic fire detection and alarm system fitted in the main part of the building also covers all flats.
f. Any security measures in any parts of the building do not prevent escape at all material times.
Use of space within protected stairways
3.78 A protected stairway should not be used for anything else, except a lift well or electricity meters.
Electricity meter(s) in protected stairways
3.79 In single stair buildings, electricity meters should be in securely locked cupboards. Cupboards should be separated from the escape route by fire resisting construction.
Gas service and installation pipes in protected stairways
3.80 Gas service and installation pipes and meters should not be within a protected stairway, unless installed in accordance with the Pipelines Safety Regulations 1996 and the Gas Safety (Installation and Use) Regulations 1998.
Exits from protected stairways
3.81 Every protected stairway should lead to a final exit, either directly or via a protected exit passageway. Any protected exit corridor or stair should have the same standard of fire resistance and lobby protection as the stair it serves.
Construction of escape stairs
3.82 The flights and landings of escape stairs should be constructed of materials achieving class A2-s3, d2 or better in all of the following situations.
a. If the escape stair is the only stair in a building with more than three storeys.
b. If the escape stair is within a basement storey.
c. If the escape stair serves any storey that has a floor level more than 18m above ground or access level.
d. If the escape stair is an external escape stair, except where the stair connects the ground storey or ground level with a floor or flat roof a maximum of 6m above or below ground level.
e. If the escape stair is a firefighting stair.
Materials achieving class B-s3, d2 or worse may be added to the top horizontal surface, except on firefighting stairs.
3.83 Further guidance on the construction of firefighting stairs is given in Section 15 (see also paragraph 3.60). Dimensional constraints on the design of stairs are given in Approved Document K.
Single steps
3.84 Single steps on escape routes should be prominently marked. A single step on the line of a doorway is acceptable, subject to paragraph 3.107.
Fixed ladders
3.85 Fixed ladders should not be provided as a means of escape for members of the public. They should only be provided where a conventional stair is impractical, such as for access to plant rooms which are not normally occupied.
Helical stairs and spiral stairs
3.86 Helical stairs and spiral stairs may form part of an escape route provided they are designed in accordance with BS 5395-2. If they are intended to serve members of the public, stairs should be type E (public) stairs.
Fire resistance of doors
3.87 Fire resistance test criteria are set out in Appendix C. Standards of performance are summarised in Table C1.
Fire resistance of glazed elements
3.88 If glazed elements in fire resisting enclosures and doors can only meet the required integrity performance, their use is limited. These limitations depend on whether the enclosure forms part of a protected shaft (see Section 7) and the provisions set out in Appendix B, Table B5. If both integrity and insulation performance can be met, there is no restriction in this document on the use or amount of glass.
3.89 Glazed elements should also comply with the following, where necessary.
a. If the enclosure forms part of a protected shaft: Section 7.
b. Appendix B, Table B5.
c. Guidance on the safety of glazing: Approved Document K.
Doors on escape routes
3.90 Doors should be readily openable to avoid undue delay to people escaping. Doors on escape routes (both within and from the building) should comply with paragraphs 3.91 to 3.98. Guidance on door closing and ‘hold open’ devices for fire doorsets is set out in Appendix C.
NOTE: Paragraphs 3.91 to 3.98 do not apply to flat entrance doors.
Door fastenings
3.91 In general, doors on escape routes (whether or not the doors are fire doorsets) should be either of the following.
a. Not fitted with a lock, latch or bolt fastenings.
b. Fitted only with simple fastenings that are all of the following.
i. Easy to operate; it should be apparent how to undo the fastening.
ii. Operable from the side approached by people escaping.
iii. Operable without a key.
iv. Operable without requiring people to manipulate more than one mechanism. Doors may be fitted with hardware to allow them to be locked when rooms are empty.
If a secure door is operated by code or combination keypad, swipe or proximity card, biometric data, etc., a security mechanism override should be possible from the side approached by people escaping.
3.92 Electrically powered locks should return to the unlocked position in all of the following situations.
a. If the fire detection and alarm system operates.
b. If there is loss of power or system error.
c. If the security mechanism override is activated.
Security mechanism overrides for electrically powered locks should be a Type A call point, as described in BS 7273-4. The call point should be positioned on the side approached by people escaping. If the door provides escape in either direction, a call point should be installed on both sides of the door.
3.93 Guidance on door closing and ‘hold open’ devices for fire doorsets is set out in Appendix C.
Direction of opening
3.94 The door of any doorway or exit should be hung to open in the direction of escape whenever reasonably practicable. It should always be hung to open in the direction of escape if more than 60 people might be expected to use it during a fire.
Amount of opening and effect on associated escape routes
3.95 All doors on escape routes should be hung to meet both of the following conditions.
a. Open by a minimum of 90 degrees.
b. Open with a swing that complies with both of the following.
i. Is clear of any change of floor level, other than a threshold or single step on the line of the doorway.
ii. Does not reduce the effective width of any escape route across a landing.
3.96 Any door opening towards a corridor or a stair should be recessed to prevent its swing encroaching on the effective width.
Vision panels in doors
3.97 Doors should contain vision panels in both of the following situations.
a. Where doors on escape routes divide corridors.
b. Where doors are hung to swing both ways.
Approved Document M contains guidance about vision panels in doors across accessible corridors and Approved Document K contains guidance about the safety of glazing.
Revolving and automatic doors
3.98 Where revolving doors, automatic doors and turnstiles are placed across escape routes they should comply with one of the following.
a. They are automatic doors of the required width and comply with one of the following conditions.
i. Their failsafe system provides outward opening from any open position.
ii. They have a monitored failsafe system to open the doors if the mains electricity supply fails.
iii. They failsafe to the open position if the power fails.
b. Non-automatic swing doors of the required width are provided immediately adjacent to the revolving or automatic door or turnstile.
Lifts
Fire protection of lift installations
3.99 Lift wells should comply with one of the following conditions.
a. Be sited within the enclosures of a protected stairway.
b. Be enclosed with fire resisting construction (minimum REI 30) when in a position that might prejudice the means of escape.
3.100 A lift well connecting different compartments should form a protected shaft (see Section 7).
3.101 In buildings designed for phased evacuation or progressive horizontal evacuation, if the lift well is not within the enclosures of a protected stairway, its entrance should be separated at every storey by a protected lobby (minimum REI 30).
3.102 In basements and enclosed car parks, the lift should be within the enclosure of a protected stairway. Otherwise, the lift should be approached only via a protected lobby or protected corridor (minimum REI 30).
3.103 If a lift delivers into a protected corridor or protected lobby serving sleeping accommodation and also serves a storey containing a high fire risk (such as a kitchen, communal areas, stores, etc.) then the lift should be separated from the high fire risk area(s) by a protected lobby or protected corridor (minimum REI 30).
3.104 A lift shaft serving storeys above ground level should not serve any basement, if either of the following applies.
a. There is only one escape stair serving storeys above ground level and smoke from a basement fire would adversely affect escape routes in the upper storeys.
b. The lift shaft is within the enclosure to an escape stair that terminates at ground level.
3.105 Lift machine rooms should be sited over the lift well where possible. Where buildings or part of a building with only one stairway make this arrangement impractical, the lift machine room should be sited outside the protected stairway.
Final exits
3.106 People should be able to rapidly leave the area around the building. Direct access to a street, passageway, walkway or open space should be available. The route away from the building should comply with the following.
a. Be well defined.
b. If necessary, have suitable guarding.
3.107 Final exits should not present a barrier for disabled people. Where the route to a final exit does not include stairs, a level threshold and, where necessary, a ramp should be provided.
3.108 Final exit locations should be clearly visible and recognisable.
3.109 Final exits should avoid outlets of basement smoke vents and openings to transformer chambers, refuse chambers, boiler rooms and similar risks.
Requirement B2: Internal fire spread (linings)
This section deals with the following requirement from Part B of Schedule 1 to the Building Regulations 2010.
Requirement
Internal fire spread (linings)
B2. (1) To inhibit the spread of fire within the building, the internal linings shall—
(a) adequately resist the spread of flame over their surfaces; and
(b) have, if ignited, either a rate of heat release
or a rate of fire growth, which is reasonable in the circumstances.
(2) In this paragraph “internal linings” means the materials or products used in lining any partition, wall, ceiling or other internal structure.
Limits on application
Intention
In the Secretary of State’s view, requirement B2 is met by achieving a restricted spread of flame over internal linings. The building fabric should make a limited contribution to fire growth, including a low rate of heat release.
It is particularly important in circulation spaces, where linings may offer the main means by which fire spreads and where rapid spread is most likely to prevent occupants from escaping.
Requirement B2 does not include guidance on the following.
a. Generation of smoke and fumes.
b. The upper surfaces of floors and stairs.
c. Furniture and fittings.
