68.—(1) In every ship in which machinery essential for the propulsion and safety of the ship or of persons on board is required to be started, operated or controlled solely by compressed air, there shall be provided at least two independently driven air compressors each of which shall be of efficient design and of sufficient strength and capacity for the service for which it is intended.
(2) Every ship which is propelled by compression ignition engines designed to start by compressed air shall be provided with at least two air receivers.
(3) Every air receiver and air bottle shall be fitted with means of access for purposes of inspection and shall be provided with efficient drains for the removal of oil and water and with efficient relief valves to prevent overpressure. If the air receiver or air bottle can be isolated from the relief valve, it shall be fitted with one or more fusible plugs so as to discharge its contents in the event of fire.
(4) The main air starting arrangements for main propulsion internal combustion engines shall be adequately protected against the effects of internal explosions and backfiring in the starting air pipes.
(5) Where an emergency air compressor is included and essential in the dead start arrangements, it is to be subject to regular inspection and testing.