Canada Occupational Health and Safety Regulations — 5.11
5.11 (1) Every high pressure boiler and every low pressure steam boiler in use at a work place shall be inspected (a) externally, at least once each year; and (b) internally, at least once every two years. (2) Every low pressure hot water boiler and every unfired boiler in use at a work place shall be inspected (a) externally, at least once every two years; and (b) internally, at least once every four years. (3) Every low pressure organic fluid boiler in use at a work place shall be inspected (a) externally, at least once every two years; and (b) internally, at least once every three years. (4) Every waste heat boiler in use at a work place shall be inspected (a) externally, at least once every year; and (b) internally, (i) at least once every two years, or (ii) where ultrasonic thickness measurements are performed annually by an NDT technician, at least once every three years. (5) Pressure vessels, other than buried pressure vessels, that have a corrosion rate exceeding 0.1 mm of metal loss per year shall be inspected (a) externally, at least once every year; and (b) internally, (i) at least once every two years, or (ii) if ultrasonic thickness measurements are performed annually by an NDT technician on representative sections of the pressure vessel, at least once every three years. (6) Pressure vessels, other than buried pressure vessels, that have a corrosion not exceeding 0.1 mm of metal loss per year shall be inspected (a) externally, at least once every year; and (b) internally, (i) at least once every four years, or (ii) if ultrasonic thickness measurements are performed annually by an NDT technician on representative sections of the pressure vessel, at least once every six years. (7) Air receivers shall be inspected (a) externally, at least once every year; and (b) internally, at least once every five years. (8) If the known corrosion rate of a pressure vessel is zero, internal inspection is not necessary provided that complete external inspections, including nondestructive thickness measurements performed by an NDT technician, are made at least once every two years on the pressure vessel and the following conditions are met: (a) the non-corrosive nature of the service conditions, including the effect of trace components, has been established by at least five continuous years of comparable service experience with the fluid being handled; (b) the periodic external inspection indicates that the condition of the pressure vessel does not warrant any further investigation; (c) the operating temperature and pressure of the pressure vessel does not exceed the lower limits for the creep rupture range of the vessel metal; and (d) the pressure vessel is protected against inadvertent contamination, and there is no evidence of contamination. (9) If a pressure vessel is used to store anhydrous ammonia, the internal inspection frequency referred to in paragraph (5)(b) may be replaced by an internal inspection conducted at least once every five years if, at the same time, a hydrostatic test at a pressure equal to one and one-half times the maximum allowable working pressure is conducted. SOR/2001-284, s. 1; SOR/2014-142, s. 4(F)