(a) Each exhaust type mechanical ventilation system required under § 154.1200 (a) must have ducts for vapors from the following:
- (1) The deck level.
- (2) Bilges.
- (3) If the vapors are lighter than air, the top of each space that personnel enter during cargo handling operations.
- (b) The discharge end of each duct under paragraph (a) of this section must be at least 10 m (32.8 ft.) from ventilation intakes and openings to accommodations, service, control station, and other gas-safe spaces.
- (c) Each ventilation system under § 154.1200 (a) and (b)(1) must change the air in that space and its adjoining trunks at least 30 times each hour.
- (d) Each ventilation system for a gas-safe cargo control station in the cargo area must change the air in that space at least eight times each hour.
- (e) A ventilation system must not recycle vapor from ventilation discharges.
- (f) Each mechanical ventilation system must have its operational controls outside the ventilated space.
- (g) No ventilation duct for a gas-dangerous space may pass through any machinery, accommodation, service, or control space, except as allowed under § 154.703.
- (h) Each electric motor that drives a ventilation fan must not be within the ducts for any space that may contain flammable cargo vapors.
(i) Ventilation impellers and the housing in way of those impellers on a flammable cargo carrier must meet one of the following:
- (1) The impeller, housing, or both made of non-metallic material that does not generate static electricity.
- (2) The impeller and housing made of non-ferrous material.
- (3) The impeller and housing made of austenitic stainless steel.
- (4) The impeller and housing made of ferrous material with at least 13mm (0.512 in.) tip clearance.
- (j) No ventilation fan may have any combination of fixed or rotating components made of an aluminum or magnesium alloy and ferrous fixed or rotating components.
- (k) Each ventilation intake and exhaust must have a protective metal screen of not more than 13mm (0.512 in.) square mesh.