(a)     No person shall be compelled or allowed, by the owner or person in charge, to go inside a steam boiler for any purpose whatsoever unless the boiler is effectively disconnected in the manner hereinafter prescribed from any steam or hot water communication with any other boiler.

Where power is used for working any equipment inside a boiler the metallic portion of the equipment shall be effectively earthed.

(b)     Effective disconnection shall be made either by the removal of the boiler stop valve or of a length of piping from all stream and hot water connections with any other boiler, vessel or pipe containing steam or hot water or by the insertion of substantial blank flanges between the boiler stop valves and piping. The shutting of a stop valve, stop cock or automatic isolating valve alone shall not be deemed to constitute compliance with this Regulation. In the case of welded pipe work, however, if a vent pipe of not less than 2” internal diameter (bore) is fitted between the main stop valve and the intermediate stop valve on the feed line, this Regulation shall be considered to have been complied with, provided such vent pipes are fitted with bolted-on blank flanges and the flanges are removed so as to effectively discharge any leakage steam or water to the atmosphere when the valves on either side of its have been closed.

(c)     The owner of a boiler to which this Regulation is applicable shall obtain the approval of the Chief Inspector in writing to the method of disconnection which he proposes to use and shall be responsible for ensuring that the method of disconnection which he proposes to use and shall be responsible for ensuring that the method so approved is followed in practice.

(d)     When electric light is used for work inside a boiler shell or drum or any confined space within a boiler, the voltage shall not exceed 24 volts and the owner of the boiler shall provide a hand lamp with lamp-guard, keyless socket, insulated handle and extension cord of approved type.