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) > 32.56-60—Ventilation ducts—T/ALL.

32.56-60—Ventilation ducts—T/ALL.

(a) Each duct for ventilation of Category A machinery spaces that passes through accommodation, service, or control spaces must be:
(1) Constructed of steel and insulated to “A-60” Class; or
(2) Constructed of steel, fitted with an automatic fire damper at each boundary where it enters and leaves the Category A machinery space, and insulated to “A-60” Class for a distance of 5 meters (16.4 feet) beyond each machinery space boundary.
(b) Each duct for ventilation of accommodation, service, and control spaces that passes through Category A machinery spaces must be constructed of steel and be fitted with an automatic fire damper at each Category A machinery space boundary.