Items where Subject is "Section 02: Means of escape – dwellinghouses"
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- Section 02: Means of escape – dwellinghouses (29)
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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. Courtyards or inaccessible back gardens should comply with Diagram 2.5.
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.
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 2.10.
f. A gallery that complies with paragraph 2.15.
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 2.11.
b. The access rooms each have a smoke alarm (see Section 1).
c. None of the access rooms is a kitchen.
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).
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.
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 2.10, where the gallery floor is a maximum of 4.5m above ground level.
c. It should meet all the conditions shown in Diagram 2.6.
Basement storeys containing habitable rooms should have one of the following.
a. An emergency escape window or external door providing escape from the basement (paragraph 2.10).
b. A protected stairway (paragraph 2.5a) leading from the basement to a final exit.
Any external escape stair should meet all of the following conditions (Diagram 2.7).
a. Doors to the stair should be fire resisting (minimum E 30), except for a single exit door from the building to the top landing of a downward-leading external stair.
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 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. Stairs more than 6m in height should be protected from adverse weather. Protection should prevent the build-up of snow or ice but does not require full enclosure.
e. Glazing in areas of fire resisting construction should be fixed shut and fire resisting (in terms of integrity, but not insulation) (minimum E 30).
Work should comply with Parts K and L of Schedule 1 to the Building Regulations. When complete, the building should comply with other applicable parts of Schedule 1 to at least the same level as before.
Where an existing window would be an escape window in a new dwellinghouse, and is big enough to be used for escape purposes, then the replacement should comply with one of the following.
a. The replacement window should be sized to provide at least the same potential for escape.
b. If the existing window was larger than required for escape purposes, the opening can be reduced to the minimum described in paragraph 2.10.
See Diagram 2.1b. Where served by only one stair, all habitable rooms (excluding kitchens) should have either of the following.
a. An emergency escape window or external door, as described in paragraph 2.10.
b. Direct access to a protected stairway, as described in paragraph 2.5a.
If windows are replaced, it may be necessary to provide cavity barriers around the opening in accordance with Section 5.
Where a new storey is added through conversion to create a storey above 4.5m, both of the following should apply.
a. The full extent of the escape route should be addressed.
b. Fire resisting doors (minimum E 20) and partitions (minimum REI 30) should be provided, including upgrading the existing doors where necessary.
NOTE: Where the layout is open plan, new partitions should be provided to enclose the escape route (Diagram 2.2).
Where it is undesirable to replace existing doors because of historical or architectural merit, the possibility of retaining, and where necessary upgrading, them should be investigated.
An alternative approach to that described in paragraph 2.21 would be to comply with all of the following.
a. Provide sprinkler protection to the open-plan areas.
b. Provide a fire resisting partition (minimum REI 30) and door (minimum E 20) to separate the ground storey from the upper storeys. The door should allow occupants of the loft room access to a first storey escape window.
c. Separate cooking facilities from the open-plan area with fire resisting construction (minimum REI 30).
Two rooms may be served by a single window. A door between the rooms should provide access to the window without passing through the stair enclosure. Both rooms should have their own access to the internal stair.
Dwellinghouses with one internal stair should comply with paragraphs 2.5 and 2.6. In dwellinghouses with more than one stair, the stairs should provide effective alternative means of escape. The stairs should be physically separated by either of the following.
a. Fire resisting construction (minimum REI 30).
b. More than one room.
See Diagram 2.1c. The dwellinghouse should have either of the following. Cavity barriers or a fire resisting ceiling (minimum EI 30) should be provided above a protected stairway enclosure (Diagram 2.3). b. Alternative escape route – a top storey separated from lower storeys by fire resisting construction (minimum REI 30) and with an alternative escape route leading to its own final exit.
a. Protected stairway – a stair separated by fire resisting construction (minimum REI 30) at all storeys, that complies with one of the following.
i. Extends to a final exit (Diagram 2.2a).
ii. Gives access to a minimum of two ground level final exits that are separated from each other by fire resisting construction (minimum REI 30) and fire doorsets (minimum E 20) (Diagram 2.2b).
See Diagram 2.1d. In addition to meeting the provisions in paragraph 2.5, the dwellinghouse should comply with either of the following.
a. Provide an alternative escape route from each storey more than 7.5m above ground level. At the first storey above 7.5m, the protected stairway should be separated from the lower storeys by fire resisting construction (minimum REI 30) if the alternative escape route is accessed via either of the following.
i. The protected stairway to an upper storey.
ii. A landing within the protected stairway enclosure to an alternative escape route on the same storey. The protected stairway at or about 7.5m above ground level should be separated from the lower storeys or levels by fire resisting construction (see Diagram 2.4).
b. Provide a sprinkler system throughout, designed and installed in accordance with BS 9251.
A passenger lift serving any storey more than 4.5m above ground level should be in either of the following.
a. The enclosure to the protected stairway, as described in paragraph 2.5.
b. A fire resisting lift shaft (minimum REI 30).
Air circulation systems which circulate air within an individual dwellinghouse with a floor more than
4.5m above ground level should meet the guidance given in paragraph 2.9.
All of the following precautions should be taken to avoid the spread of smoke and fire to the protected stairway.
a. Transfer grilles should not be fitted in any wall, door, floor or ceiling of the stair enclosure.
b. Any duct passing through the stair enclosure should be rigid steel. Joints between the ductwork and stair enclosure should be fire-stopped.
c. Ventilation ducts supplying or extracting air directly to or from a protected stairway should not serve other areas as well.
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.
Image
See paras 2.1 to 2.6
Single storey dwellinghouse(see paragraph 2.1)
Dwellinghouse with one storey more than 4.5m above ground level(see paragraph 2.5)
Dwellinghouse with two or more storeys more than 4.5m above ground level(see paragraph 2.6)
See para 2.5
Fire resisting construction minimum REI 30
Fd Fire doorset minimum E 20
See para 2.5
Alternative cavity barrier arrangements in roof space over protected stairway in a house with a storey more than 4.5m above ground level
See para 2.6
Example of alternative exit in para 2.6(a) (see definition in Appendix A)
Where escape from a dwellinghouse is to an enclosed space with exit only possible through other buildings (e.g. a courtyard or back garden), the length of the space should exceed whichever is the greater of the following.
a. The height of the dwellinghouse above ground level (x).
b. Where a rear extension is provided, the height of the extension (y).
See para 2.10
NOTES:
1. This diagram does not apply where the gallery is provided with one of the following:
i. An alternative escape route
ii. An emergency escape window (where the gallery floor is not more than 4.5m above ground level).
2. Any cooking facilities within a room containing a gallery should comply with one of the following conditions:
i. Be enclosed with fire resisting construction
ii. Be remote from the stair to the gallery and positioned such that they do not prejudice escape from the gallery.
See para 2.15
Fire resisting window(minimum RE30)
No fire resistance required for door
1100mm zone above top landing
6m max. height without weather protection
1800mm zone of fire resisting construction at side of stairway
Fire doorset(minimum E30)
See para 2.17