Natural venting requirements for basement smoke outlets

A basement storey may be ventilated by smoke outlets which should – (a) be sited at ceiling level within the space they serve; (b) have an aggregate free area of not less than 2.5% of the floor area of the space they serve; (c) be distributed as evenly as possible around the perimeter of the building; (d) be located so that they do not adversely affect any escape route from the building; and (e) have a sign stating "smoke outlet from basement" fixed adjacent to each external outlet point. The smoke outlets from a place of special fire hazard should be separate from the smoke outlets from other areas.