Fire Safety in blocks of flats Â– Means of Escape Â– Flats with more than one stairway Â– Part 10
Last week’s blog on fire safety in blocks of flats, on the subject of means of escape, finished by looking at standards in blocks of flats with only one escape stairway. This week’s blog begins by looking at blocks with more than one escape stairway and the implications to fire safety.
Current benchmark design states that each flat should be separated from the common stairway by a protected lobby or corridor. This means that the construction of that lobby or corridor is such that it can withstand fire for a pre-determined length of time, has fire-resistant doors to keep fire out and has some form of ventilation to ensure it does not fill with smoke. In addition, the travel distance from each flat front door to the nearest stairway or protected lobby should be no more than 30m.
In cases where one common corridor serves more than one escape stairway, a dividing fire-resistant door (self-closing) should separate the corridor into two parts to ensure that smoke cannot spread to affect access to more than one escape stairway. However, where the maximum travel distance from any flat to the stairway or protected lobby is no more than 15m, this door can be omitted.
Any dead-end corridor should be separated from the rest of the corridor by a self-closing fire-resistant door and length of travel in a single direction of the dead end should be no more than 7.5m.
Ventilation is important to ensure smoke control and so natural or mechanical vents should be provided in the lobby or corridor adjacent to the escape stairway, as well as an open-able vent at the head of the stairway.
In the case of flats where there is an external balcony or deck access approach, it is unlikely that horizontal smoke spread would affect visibility and evacuation where the balcony or deck is less than 2m in width. There is a case for wider decks suffering from smoke spread and in these cases, downstands may be necessary to restrict the spread.
While there are no limitations on travel distances for escape routes using an external balcony or deck, there will be limitations in terms of distance from the firefighting access, with no flat being more than 45m from the firefighting vehicle access point or within 45m of a landing valve of a dry rising main.
In a block where each flat can access an alternative escape along an open balcony or deck, the flat entrance doors do not need to be fire-resistant. However, in flats with a single escape to a single escape stairway, the separating walls between flats and the balcony or deck should be fire-resisting up to a height of 1.1m from the balcony or deck level. The flat entrance doors should also be self-closing fire-resisting doors.
These fire safety precautions ensure that residents can pass safely by the flat of fire origin to reach the escape stairway.
Next week’s blog will look at external stairways and escape over rooftops. We’ll also begin to look at the implications for those blocks who do not meet the terms of the current guidance. In the meantime, if you have any queries about a project or wish to discuss this blog series, please contact Peter Gyere in the first instance on 0208 668 8663.
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