S-2.1, r. 13 - Regulation respecting occupational health and safety
304. Hot work: Wherever hot work is performed in an enclosed area, a worker may only enter or be present therein if the following conditions are met:
(1) the conditions provided under sections 302 and 303;
(2) a continuous monitoring of the concentration of inflammable gases and vapours found therein is carried out by a direct reading instrument equipped with an alarm.