(1) Doors shall have resistance to fire as far
as practicable, equivalent to the division in which they are fitted.
Doors and door frames in "A" class divisions shall be constructed
of steel. Doors in "B" class divisions shall be non-combustible. Doors
fitted in boundary bulkheads of machinery spaces of category A shall
be self-closing and reasonably gastight. The Administration may permit
the use of combustible materials in doors separating cabins from the
individual interior sanitary accommodation, such as showers, if constructed
according to method IF.
(2) Doors required to be self-closing shall not
be fitted with hold-back hooks. However, hold-back arrangements fitted
with remote release fittings of the fail-safe type may be used.
(3) Ventilation openings may be permitted in and
under the doors in corridor bulkheads except that such openings shall
not be permitted in and under stairway enclosure doors. The openings
shall be provided only in the lower half of a door. Where such opening
is in or under a door the total net area of any such opening or openings
shall not exceed 0.05 m2. When such opening is cut in a
door it shall be fitted with a grille made of non-combustible material.
(4) Watertight doors need not be insulated.