Section 21, The Machinery (Safe Working Citation

(I) All compressed air or gas receivers, intercoolers, andtheir connections to air or gas cylinders shall be kept clean and free from carbonised oil or other materials liable to ignition, and shall be opened and examined in this respect by the engineer in charge, or other duly authorised and competent person at intervals not exceeding twelve months. A written record of such inspection signed by the person making it, who shall be held responsible for compliance with this rule, shall be in the owner's possession and open to inspection by an Inspector. (2) Every compressed air or gas receiver shall be fitted with an efficient oil drain placed at the lowest point on the receiver. Any accumulation of oil in such receiver shall be removed by mea~s o~ ~uch oil drain at least every eight hours while the receiver IS In use. (3) The supply of air for compressed air receivers shall be drawn from the purest and coolest source available. (4) All cylinders, receivers, or other vessels that are subjected to a higher pressure than atmospheric pressure, other than the working cylinders or chambers of heat-engines, air-engines, or portable gas cylinders, sha.ll be fitted with satisfactory apparatus for showing the internal pressure; also with a lock-up relief or safety valve or other apparatus capable of automatically preventing any undue accumulation of pressure above the safe working limit of the vessel. The owner shall test or cause to be tested such apparatus at intervals not exceeding three years by hydraulic pressure to the extent of one and one-third times the working gauge pressure. A written record .of such test, signed by the person conducting the same shall be in the owner's possession, and open to inspection by an Inspector.