Code of Federal Regulations Title 46. Shipping § 46.32.56–60 Ventilation ducts—T/ALL

(a) Each duct for ventilation of Category A machinery spaces that passes through accommodation, service, or control spaces must be:

(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.