PART XXVII CONFINED SPACE ENTRY — Explosives or flammable atmosphere

the worker is performing only inspection, work that does not produce a source of ignition and, in the case of an explosive or flammable gas or vapour, the atmospheric concentration is less than 25% of its lower explosive limit, as determined by a combustible gas measuring instrument;

the worker is performing only cold work and, in the case of an explosive or flammable gas or vapour, the atmospheric concentration is less than 10% of its lower explosive limit as determined by combustible gas instruments; or

the worker is performing hot work and all of the following conditions are satisfied:

in the case of an explosive or flammable gas or vapour, the atmospheric concentration is less than 5% of its lower explosive limit, as determined by a combustible gas instrument, (ii) the atmosphere in the confined space does not contain, and is not likely to contain while a worker is inside, an oxygen content greater than 23%, (iii) the atmosphere in the confined space is monitored continuously, (iv) the entry permit includes adequate provisions for hot work and corresponding control measures, and

an adequate alarm system and exit procedures are provided to ensure that workers have adequate warning and are able to exit the confined space safely where either or both of the following occur, in the case of an explosive or flammable gas or vapour (A) the atmospheric concentration exceeds 5% of its lower explosive limit, or (B) the oxygen content of the atmosphere exceeds 23% by volume.