Smoke control of common escape routes by natural smoke ventilation

Department for Communities and Local Government, (2019) Smoke control of common escape routes by natural smoke ventilation. In: Approved Document B: Fire Safety - Volume 1: Dwellings. 2019 ed. Section 3: Means of escape – flats, 1 (3.51). RIBA Publishing Publication, London, p. 32. ISBN 9781859469156

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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.

Item Type: Book Section
Additional Information: mml-maui-text-analytics-keywords
Uncontrolled Keywords: fire and smoke damper, fire doorset, principal works, protected shaft, free area, principal storey, b4 external fire spread, external wall, fire damper, fire risk assessment
Subjects: T Technology > TH Building construction > Building standards > fire safety - volume 1: dwellings. 2019 edition - for use in england > Section 3: Means of escape – flats
K Law > The Building Regulations 2010 > B1: Means of warning and escape
T Technology > TH Building construction > Building standards
Date Deposited: 02 Feb 2020 12:13
Last Modified: 13 Oct 2021 19:42

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