46 CFR §108.143

1. (a)Each corridor bulkhead in an accommodation space must be an A class or B class bulkhead except if an A class bulkhead is specifically required by this part.
2. (b)No door in a corridor bulkhead in an accommodation space may have a louver, except that a stateroom, lounge, or recreation room door may have louvers in its lower half.
3. (c)Each stairtower, elevator, and dumbwaiter, and other trunk must be enclosed by A class bulkheads.
4. (d)Each bulkhead not described under paragraph (a) of this section must be either A class, B class, or C class bulkheads.
5. (e)At least one opening to each stairway must be enclosed by either A class or B class bulkheads and doors.
6. (f)Each stairtower must have doors at all levels and each must be an A class door.
7. (g)Each door required by paragraphs (e) and (f) of this section—
   1. (1)Must be self-closing;
   2. (2)May not have any means to permanently hold the door open, except for magnetic holdbacks that are operated from the bridge or other remote location.
8. (h)Interior stairs, including stringers and treads, must be made of steel or an equivalent material.
9. (i)Except in washrooms and toilet spaces, each deck covering in an accommodation space must be made of an approved material, except an overlay on a deck for leveling or finishing that is not more than 9.375 millimeters ( 3/8 inch) thick.
10. (j)Except as provided in paragraph (1), each ceiling, lining, insulation, and pipe and duct lagging in an accommodation space must be made of an approved material that is noncombustible.
11. (k)Each sheathing, furring, or holding piece used to secure a bulkhead, ceiling, lining, or insulation in an accommodation space must be made of an approved material that is non-combustible.
12. (l)No bulkhead, lining, or ceiling in an accommodation space may have a combustible veneer greater than 2 millimeters ( 1/12 inch) in thickness.
13. (m)Each corridor or hidden space in an accommodation space may be covered by an approved interior finish or a reasonable number of coats of paint. However, no corridor or hidden space may have combustible veneer, trim, or decoration except material approved under Subpart 164.012 of this chapter.