Hull Construction Regulations

170 (1) Every stairway that is located in an accommodation space, service space or control station and that penetrates only a single deck shall be protected at one level by at least ‘B-0’ Class fire rating divisions and self-closing fire doors.

(2) Every stairway that is located in an accommodation space, service space or control station and that penetrates more than a single deck shall be enclosed in a stairtower of at least ‘A-0’ Class fire rating contruction and have self-closing fire doors fitted at every level but the stairtower may be of ‘B-0’ Class fire rating construction if

• (a) there are at least two escapes giving direct access to the open deck at every accommodation level; and

• (b) the ship has accommodation for not more than 12 persons.

(3) All stairways, including stringers, treads and risers in accommodation spaces, service spaces and control stations shall be constructed of steel.