Technical Booklet E Fire Safety·Page 60·2.62
Single escape stairways
A single escape stairway may be permitted to serve a basement or a building with no storey more than 11 m above ground level, provided independent escape routes are not required and each storey is permitted to have a single escape route.
Where independent escape routes are not required from areas in different purpose groups, in accordance with paragraph 2.39, a single escape stairway may serve – (a) a basement which is permitted to have a single escape route in accordance with paragraph 2.41; or (b) a building which has no storey with a floor level more than 11 m above ground level, and in which every storey is permitted to have a single escape route in accordance with paragraph 2.41.
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