CFR > Title 46 - Shipping > CHAPTER I—COAST GUARD, DEPARTMENT OF HOMELAND SECURITY > SUBCHAPTER D—TANK VESSELS (parts 30 to 39) > PART 32—SPECIAL EQUIPMENT, MACHINERY, AND HULL REQUIREMENTS > SUBPART 32.56—Structural Fire Protection for Tank Ships With a Keel Laying Date On or After January 1, 1975 (§32.56-1 to §32.56-60) > 32.56-21—Openings in exterior boundaries: Accommodation, service, and control spaces—T/ALL.

32.56-21—Openings in exterior boundaries: Accommodation, service, and control spaces—T/ALL.

The following exterior boundaries of accommodation, service, and control spaces, except wheelhouses, must have no openings, and portlights must be of a fixed type with easily operable steel covers on the inside:
(a) The exterior boundaries that face the cargo area.
(b) The portion of the exterior boundaries within 3 meters (10 feet) or the length of the vessel divided by 25, whichever is greater, except that the distance need not exceed 5 meters (16.4 feet), of these boundaries.