(1) A good and sufficient air plant for the compression of air shall be provided to meet not only ordinary conditions, but emergencies, and to provide margin for repairs at all times. Provision must be made for storing in tanks at each boiler house enough feed water for twelve hours' supply unless connection can be made with two independent and separately sufficient sources of supply.

(2) The plant shall be capable of furnishing to each working chamber a sufficient air supply for all pressure to enable work to be done.