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[接上页] (2) (a) (i) The inert gas system shall be designed, constructed and tested to the satisfaction of the Director. It shall be so designed and operated as to render and maintain the atmosphere of the cargo tanks including the slop tanks non-flammable at all times, except where it is necessary for such tanks to be gas free; (ii) in the event that the inert gas system is unable to meet the operational requirement set out above and it has been assessed by the owner or master that it is impractical to effect a repair, then cargo discharge, deballasting and necessary tank cleaning shall only be resumed when the "emergency procedures" laid down in the "Guidelines for Inert Gas Systems" are complied with; (b) the system shall be capable of- (i) inerting empty cargo tanks including slop tanks by reducing the oxygen content of the atmosphere in each tank to a level at which combustion cannot be supported; (ii) maintaining the atmosphere in any part of any cargo or slop tank at an oxygen content not exceeding 8% by volume and at a positive pressure at all times both in port and at sea except when it is necessary for such a tank to be gas free; (iii) eliminating the need for air to enter a tank during normal operations except when it is necessary for such a tank to be gas free; and (iv) purging empty cargo tanks including slop tanks of hydrocarbon vapour, so that subsequent gas freeing operations will at no time create a flammable atmosphere within the tank;(c) (i) the system shall be capable of delivering inert gas to the cargo tanks and slop tanks at a rate of at least 125% of the maximum rate of discharge capacity of the ship, expressed as a volume; (ii) the oxygen content of the inert gas main shall not normally exceed 5% by volume;(d) the inert gas supply may be treated flue gas from the main or or auxiliary boilers, from one or more separate gas generators or other sources or from any combination thereof. The Director may approve systems using inert gases other than flue gas, provided he is satisfied that an equivalent standard of safety is achieved. Systems using stored carbon dioxide shall not be permitted unless the Director is satisfied that the risk of ignition from generation of static electricity by the system itself is minimized; (e) flue gas isolating valves shall be fitted in the inert gas supply mains between the boiler uptakes and the flue gas scrubber. These valves shall be provided with indicators to show whether they are open or shut, and precautions shall be taken to maintain them gas-tight and keep the seating clear of soot. Arrangements shall be made so that boiler soot blowers cannot be operated when the corresponding flue gas valve is open; (f) (i) a flue gas scrubber shall be fitted which will effectively cool the volume of gas specified in paragraph (c) and remove solids and sulphur combustion products. The cooling water arrangements shall be such that an adequate supply of water will always be available without interfering with any essential services on the ship. Provision shall be made for an alternative supply of cooling water; (ii) filters or equivalent devices shall be fitted to minimise the amount of water carried over to the inert gas blowers;(g) (i) at least 2 blowers shall be fitted which together shall be capable of delivering to the cargo tanks and slop tanks, at least the volume of gas required by paragraph (c). In a system provided with a gas generator, the Director may permit only one blower if that system is capable of delivering the total volume of gas required by paragraph (c) to the protected cargo tanks, on condition that sufficient spares and replacement parts for the blower and its prime mover are carried on board to enable any failure of the blower and its prime mover to be rectified by the ship's crew; (ii) 2 fuel oil pumps shall be fitted |