5.5.1 A ventilator should be of efficient construction
and, where situated on the weather deck and not complying with Section
5.5.3, should be provided with a readily available means of weathertight
closure, consideration should be given to requirements of Fire Protection
(Section 14).
5.5.2 A ventilator should be kept as far inboard
as practicable and the height above the deck of the ventilator opening
should be sufficient to prevent the ready admission of water when
the vessel is heeled. (See Sections 11.3, 11.4,
11.6, and 11.8.)
5.5.3 A ventilator which must be kept open, e.g.
for the supply of air to machinery or for the discharge of noxious
or flammable gases, should be specially considered with respect to
its location and height above deck having regard to Section 5.5.2
and the downflooding angle. (See Sections 11.3,
11.4, 11.6, and 11.8.)
5.5.4 Motor vessels which are fitted with engine
air intakes in the hull side, which do not satisfy the requirements
of the Code may be accepted by a Certifying Authority, but restrictions
on operations may be necessary.
5.5.5 An engine exhaust outlet which penetrates
the hull below the weather deck should be provided with means to prevent
backflooding into the hull through the exhaust system. The means may
be provided by system design and/or arrangement, built-in valve or
a portable fitting which can be applied readily in an emergency.