(a) The hull, superstructure, structural bulkheads, decks, and deckhouses shall be constructed of steel. Alternately, the Commandant may permit the use of other suitable material in special cases, having in mind the risk of fire.
(b) Bulkheads of galleys, paint and lamp lockers, and emergency generator rooms shall be of ``A'' Class construction.
(c) The boundary bulkheads and decks separating the accommodations and control stations from cargo and machinery spaces, galleys, main pantries and storerooms, other than small service lockers, shall be of ``A'' Class construction.
(d) Within the accommodation and service areas the following conditions shall apply:
(1) Corridor bulkheads in accommodation spaces shall be of the ``A'' or ``B'' Class intact from deck to deck. Stateroom doors in such bulkheads may have a louver in the lower half.
(2) Stairtowers, elevator, dumbwaiter, and other trunks shall be of ``A'' Class construction.
(3) Bulkheads not already specified to be of ``A'' or ``B'' Class construction may be of ``A'', ``B'', or ``C'' Class construction.
(4) The integrity of any deck in way of a stairway opening, other than a stairtower, shall be maintained by means of ``A'' or ``B'' class bulkheads and doors at one level. The integrity of a stairtower shall be maintained by ``A'' Class doors at every level. The doors shall be of self-closing type. Holdback hooks, or other means of permanently holding the door open will not be permitted. However, magnetic holdbacks operated from the bridge or from other suitable remote control positions are acceptable.
(5) Interior stairs, including stringers and treads, shall be of steel.
(6) Except for washrooms and toilet spaces, deck coverings within accommodation spaces shall be of an approved type. However, overlays for leveling or finishing purposes which do not meet the requirements for an approved deck covering may be used in thicknesses not exceeding \3/8\ of an inch.
(7) Ceilings, linings, and insulation, including pipe and duct laggings, shall be of approved incombustible materials.
(8) Any sheathing, furring or holding pieces incidental to the securing of any bulkhead, ceiling, lining, or insulation shall be of approved incombustible materials.
(9) Bulkheads, linings, and ceilings may have a combustible veneer within a room not to exceed \2/28\ of an inch in thickness. However, combustible veneers, trim, decorations, etc., shall not be used in corridors or hidden spaces. This is not intended to preclude the use of an approved interior finish or a reasonable number of coat of paint.
(e) Wood hatch covers may be used between cargo spaces or between stores spaces. Hatch covers in other locations shall be of steel or equivalent metal construction. Tonnage openings shall be closed by means of steel plates.
(f) Nitrocellulose or other highly flammable or noxious fume-producing paints or lacquers shall not be used.
(g) The provisions of paragraph (d) (1) through (9) of this section apply to control spaces on vessels whose initial Application for Inspection is submitted to an Officer in Charge, Marine Inspection on or after June 15, 1987. [CGFR 65-50, 30 FR 16983, Dec. 30, 1965, as amended by CGFR 67-90, 33 FR 1015, Jan. 26, 1968; CGD 84-073, 52 FR 18364, May 15, 1987; 52 FR 22751, June 15, 1987]