Width of escape stairs

An escape stair should be wide enough to accommodate the appropriate number of people assessed as being likely to use it. This width depends on the number of stairways provided and whether the escape strategy is based on simultaneous evacuation (see paragraph 2.65) or phased evacuation (see paragraph 2.66). In any event an escape stair should – (a) be not less than the appropriate dimension given in Table 2.5; (b) be not less than the width required for any storey exit giving access to it; (c) not reduce in width at any point on its way to the final exit; and (d) not exceed 1400 mm if the vertical extent of the escape stair is more than 30 m, unless it is at least 1800 mm and it is provided with a central handrail. In such a case the width on each side of the handrail should be considered separately for the purpose of assessing stair capacity. (Research indicates that people prefer to stay within reach of a handrail when making a prolonged descent, consequently the centre part of a wide stair is little used and could be hazardous).