Technical Booklet E Fire Safety·Page 144·5.17
Method 2: Small Buildings and Compartments - Unprotected Areas
For buildings and compartments up to 10 m in height (except Purpose Group 7(b)), the maximum total percentage of unprotected area in a building's side is determined by the distance between that side and the relevant boundary, with limits varying by purpose group as specified in Table 5.3.
This method may be used for buildings and compartments of any purpose group which do not exceed 10 m in height [this height limit does not apply to buildings of Purpose Group 7(b)]. The maximum total percentage of unprotected area in the side of a building should not exceed that given in Table 5.3 for the appropriate purpose group and minimum distance between that side and its relevant boundary. When calculating the unprotected area, any area which complies with paragraph 5.10 and Diagram 5.4 may be discounted.
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