53.Ventilation system: Any ventilation system for removing flammable vapours or gases that may present a danger of fire or explosion shall:
(1) be made of non-combustible substances;
(2) use ventilators whose rotating parts are made of materials that do not produce sparks;
(3) have all metallic components bonded together and commonly grounded or grounded separately to a grounding network with equivalent conductivity so as to prevent the accumulation of static electricity;
(3.1) have all non-metallic components built and installed to first limit the accumulation of static electricity under a safety threshold and then to prevent such an accumulation in excess of the safety threshold;
(4) be equipped with airtight exhaust conduits oriented directly outdoors without ever passing through an intermediate room, and built to resist explosions.