Mechanical ventilation of unberthed
passenger spaces.
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(b) have an area at least 50 per centum greater than that of
its coaming.
(7) Every ventilator coaming shall-
(a) project to the bottom of the beam of the compartment
that it serves:
(b) be measured at the narrowest part of the air passage:
and
(c) not exceed 452 square inches in area (24 inches in
diameter); and
(d) be not less than 78.5 square inches in area (10 inches
in diameter).
(8) If less than 4 ventilators are fitted to any one compart- ment, suitable trunks shall be provided to ensure proper distribu- tion of air, except where any such ventilator does not exceed 15 inches in diameter, in which case, such trunking shall not be required.
(9) If an odd number of ventilators is fitted, the prescribed inlet and exhaust areas shall be maintained.
(10) If any trunking or air passage has a curved bend or kucs and the angle does not exceed 30°, no additional area is required to be provided; but for any curved bend or knee of which the angle exceeds 30°, the following additions to the area shall be made-
(a) for curved bends of angles ranging between 30° to 60*. 5 per centum additional area for each such curved bend: (b) for curved bends of angles ranging between 60° to 90", 10 per centum additional area for each such curved bend: (c) for knees of angles ranging between 30° to 60°, 16 per
centum additional area for each such knee; and
(d) for knees of angles ranging between 50° to 90°, 36 per
centum additional area for each such knee.
(11) If the radius of the inner side of any curved bend is less than the diameter of the trunk or air passage, the bend shall be regarded as a knee.
23. (1) In every ship to which these regulations apply engaged in the eastern trade area, other than a ship engaged exclusively in the river trade area, every space allocated for the accommodation of unberthed passengers situated-
(a) below the uppermost between deck; or
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(b) in a compartment in an upper between deck that is
completely covered by a long superstructure.
shall be ventilated by a trunked mechanical ventilation or other air change system approved by the Director:
Provided that, where such an uppermost between deck space or long superstructure has large openings in the sides of the ship with no means fitted whatsoever of closing the openings. the unberthed passenger compartment in the between deck next below and adjacent to such openings may, subject to the approval of the Director, be regarded as an uppermost between deck and may be exempt from the requirement to be ventilated by a trucked mechanical ventilation or other air change system.
(2) The approval, on completion, of any system of mechanical ventilation shall be conditional upon the results of anemometer tests with which the Director is satisfied that the system is efficient.
(3) Arrangements shall be made to ensure a sufficient supply of air in the event of a breakdown in any part of a mechanical ventilation system—
(a) by interconnecting the air ducts from two or more fans; (b) by providing additional independent means of mechanical
ventilation; or
(c) by providing spare gear, properly packed for storage. for each size of electric motor employed to operate any tranked mechanical ventilation or other air change system on the following scale-
(i) for direct current motors
1 armature
1 field coil
1 set of bearings
1 brush bolder
1 set of carbon brushes; and
(i) for alterating current motors—
I set of stator windings, complete with insulation
pieces
1 set of bearings.
(4) A trunked mechanical ventilation system, required to be fitted to any space pursuant to this regulation. shall be capable of delivering, under normal sea-going conditions, for each passenger of the maximum number for which the space may measure, at least 830 cubic feet of fresh air per hour.