47. The plan referred to in section 46 must cover all of the following equipment parts:
(1) gate valves and other valves of a diameter equal to or greater than 1.875 cm;
(2) pump, compressor and agitator seals;
(3) joints or connections of a diameter equal to or greater than 1.875 cm; and
(4) open pipes.
Equipment maintained under negative pressure or completely covered with thermal insulation is excluded from the plan.
For the purposes of this section, an open pipe means a gate valve or a valve, except a pressure relief valve, with one side of the seat in contact with one of the substances referred to in section 46 and the other side exposed to the atmosphere.