External stairs as part of escape routes - weather protection and fire-resisting construction

Where an external stair is part of an escape route – (a) the stair should be protected from the weather when it serves a floor or flat roof more than 6 m above ground level. The degree of protection from the weather will depend on the exposure of the stair; (b) all doors giving access to the stair should be fire-resisting except at the top of any stair which leads downwards; (c) any part of the external walls within 1.8 m of the stair (measured horizontally) should be of fire-resisting construction – (i) 1.8 m above (this may be reduced to 1.1 m at the top landing of the stair provided that it is not the top landing of a basement stair); (ii) 1.8 m at the side of; and (iii) 9 m below, the flights and landings of the stair as shown on Diagram 2.11; (d) the external walls of the building within 1.8 m of the escape route from the bottom of the stair should be fire-resisting to a height of 1.1 m above the escape route; and (e) glazing in fire-resisting external walls described in (c) and (d) above should also be fire-resisting and fixed shut (see Table 2.8 for the limitations on the use of uninsulated glazing).