Section
11 Ventilators
11.1 General
11.1.1 This
Section provides requirements for ventilators and the ventilation
of all craft.
11.1.2 The requirements
conform, where relevant, with those of the International Convention
on Load Lines, 1966. Reference is also to be made to any additional
requirements of the National Authority of the country in which the
craft is to be registered and to the relevant regulations of the International
Convention for the Safety of Life at Sea, 1974 and applicable
amendments.
11.1.3 Special
care is to be taken in the design and positioning of ventilator openings
and coamings, particularly in the region of the forward end of superstructures
and other points of high stress. The deck plating in way of the coamings
is to be efficiently stiffened.
11.1.4 The scantlings
of ventilators exposed to the weather are to be equivalent to those
of the adjacent deck or bulkhead. Where the height of the ventilator
exceeds that required by Pt 3, Ch 4, 11.5 Effective coaming heights 11.5.1,
the thickness may be gradually reduced above that height to a minimum
which will be specially considered dependent on the material of construction.
Ventilators are to be adequately stayed.
11.1.5 Ventilators
from deep tanks and tunnels passing through 'tween decks are to have
scantlings suitable for withstanding the pressures to which they may
be subjected, and are to be made watertight.
11.1.7 Adequate
ventilation is to be provided throughout the craft.
11.2 Accommodation spaces
11.3 Machinery spaces
11.3.1 In addition
to the requirements of this Section, a filter coalescer is to be fitted
to the machinery space air intakes to remove fine spray where:
- Intakes are fitted in exposed positions on the weather deck; or
- intakes are large; or
- coaming height is reduced; or
- as required by the engine manufacturer.
Special consideration will be given to alternative arrangements
for craft operating within Service Groups G1-G3, see
also
Pt 9 General Requirements for Machinery.
11.3.2 In general,
ventilators necessary to continuously supply the machinery space or
the emergency generator room shall have coamings of sufficient height
to comply with Pt 3, Ch 4, 11.4 Closing appliances 11.4.1, without
having to fit weathertight closing appliances.
11.3.3 Where
it is not practical to comply with Pt 3, Ch 4, 11.3 Machinery spaces 11.3.2 due
to ship size and arrangement, lesser heights for machinery space and
emergency generator room ventilator coamings, fitted with weathertight
closing may be permitted by the Administration in combination with
other suitable arrangements to ensure an uninterrupted, adequate supply
of ventilation to these spaces.
11.3.4 Where closing appliances are fitted as per Pt 3, Ch 4, 11.3 Machinery spaces 11.3.3 or
Pt 3, Ch 4, 11.4 Closing appliances 11.4.2, to ventilators
serving emergency generator rooms or closable ventilation louvres are used for emergency
generator rooms, the following requirements are to be applied in addition to the
requirements of Pt 3, Ch 4, 11.3 Machinery spaces 11.3.3:
- Ventilation louvres and closing appliances may either be
hand-operated or power-operated (hydraulic/pneumatic/electric) and are to be
operable under a fire condition. Closing appliances, which automatically close in
response to exposure to fire products, are not to be fitted on ventilators located
at outside boundaries and serving emergency generator rooms.
- Hand-operated ventilation louvres and closing appliances are to be
kept open during the normal operation of the vessel. Corresponding instruction
notices are to be provided at the location where hand operation is provided.
- Power-operated ventilation louvres and closing appliances are to
open automatically whenever the emergency generator is starting/in operation.
Closed ventilation louvres and closing appliances are acceptable during normal
operation of the vessel. In the event of power failure, the default position of
the ventilation louvres or closing appliances is to be the open position.
- Ventilation openings are to be capable of being operated manually
from a clearly marked safe position outside the space where the closing operation
can be easily confirmed. The louvre status (open/closed) is to be indicated at
this position. Such closing is not to be possible from any other remote
position.
11.4 Closing appliances
11.4.1 All ventilator
openings are to be provided with efficient weathertight closing appliances
unless:
-
The height of the
coaming is greater than 4,5 m above the deck at Position 1.
-
The height of the
coaming is greater than 2,3 m above the deck at Position 2.
11.4.2 In order to limit the fire growth potential in every space of the ship, the
main inlets and outlets of all ventilation systems shall be capable of being closed from
outside the spaces being ventilated. The means of closing shall be easily accessible as
well as be prominently and permanently marked and shall indicate whether the inlet or
outlet is open or closed. Unless required by SOLAS, Chapter II-2, Part C, Regulation 9 - Containment of fire or applicable
statutory instruments, emergency generator room ventilators need to be fitted with such
means of closing, only when the emergency generator room is fitted with a fixed gas
fire-fighting system. Battery room ventilators are to be fitted with a means of closing
only when:
-
the battery room
does not open directly onto an exposed deck; or
-
the ventilation
opening for the battery room is required to be fitted with a closing
device according to the Load Line Convention; or
-
the battery room
is fitted with a fixed gas fire-extinguishing system.
Where a battery room ventilator is fitted with a closing device, see
Pt 16, Ch 2, 11.5 Construction 11.5.2. The means of closing mentioned in this
paragraph refers to closing appliances of ventilation inlets and outlets for minimising
the potential fire growth. The requirements specified are distinct from those for
weathertight closing appliances.
11.4.3 Closing
appliances are to be permanently attached to the ventilator coaming.
11.4.4 Where,
in ferries, ventilators are proposed to be led overboard in an enclosed
'tween deck, the closing arrangements are to be submitted for approval.
If such ventilators are led overboard more than 4,5 m above the main
vehicle deck, closing appliances may be omitted, provided that satisfactory
baffles and drainage arrangements are provided, as in the case of
air intakes or exhaust openings for machinery spaces, which may be
arranged in the sides of the craft.
11.4.5 Mushroom
ventilators closed by a head revolving on a centre spindle (screw
down head) are acceptable in Position 2, and also in sheltered positions
in Position 1, but the diameter is not to exceed 300 mm if situated
within the forward 0,25L
L.
11.4.6 Mushroom
ventilators with a fixed head and closed by a screw down plate (screw
down cover) may be accepted in exposed positions within the forward
0,25L
L up to a diameter of 750 mm.
11.4.7 Wall
ventilators (jalousies) may be accepted provided they are capable
of being closed weathertight by hinged gasketed covers secured by
bolts or toggles. They are preferably to face aft or athwartships
and are to be fitted with a suitable means of preventing ingress of
water and spray when open in the form of louvres, baffles, screens
or an equivalent arrangement.
11.5 Effective coaming heights
11.5.1 The height
of ventilator coamings exposed to the weather is to be as high as
practicable, with a minimum height of 600 mm in Position 1 and 450
mm in Position 2. In particularly exposed positions, the height of
coamings may be required to be increased or self closing devices may
be required.
11.5.2 Reduced
coaming heights may be considered for ventilators which are not required
for the operation of the craft at sea, provided that operational procedures
are in place and a notice is fitted to the ventilator to ensure that
the closing device is closed whilst the craft is at sea.
11.5.3 For gooseneck
ventilators, the coaming height is to be measured to the underside
of the bend, this being the lowest point through which water on deck
could pass freely to spaces below.
11.5.4 Where
wall ventilators are fitted with an internal baffle which rises above
the lower edge of the exterior opening, the coaming height is measured
to the top of the baffle.
11.6 Drainage arrangements
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