8.35. After an underground tank has been set in the excavation, it must undergo the leak tests listed below that are to be conducted in compliance with the following requirements: (1) for the inner wall of a tank,
(a) all the tank’s caps must be removed and steel caps must be installed, after a joint compound or tape has been applied that meets the requirements of section 8.69;
(b) a safety valve set to a pressure of not more than 40 kPa capable of discharging the flow from the pressure source must be installed on a tank opening and its operation inspected before each test;
(c) the pressure inside the tank and in its interstitial space must be measured simultaneously using a pressure gauge calibrated in units of not more than 1 kPa;
(d) a pressure of at least 30 kPa and not more than 35 kPa must be created inside the tank; and
(e) the pressure in the interstitial space must remain stable;
(2) for the outer wall of a tank,
(a) the pressure inside the tank and in its interstitial space must be measured simultaneously using a pressure gauge calibrated in units of not more than 1 kPa;
(b) the pressure source must come from the inside part of the tank and be transferred into the interstitial space until it reaches a pressure of at least 30 kPa and not more than 35 kPa; a tank manufactured under CAN/ ULC Standard S603.1, External Corrosion Protection Systems for Steel Underground Tanks for Flammable and Combustible Liquids, published by Underwriters’ Laboratories of Canada, may be pressurized according to the manufacturer’s instructions;
(c) it must be tested using leak detection fluid; and
(d) the interstitial space of a fibreglass tank must be inspected according to the manufacturer’s recommendations.
During the tests, once the temperature has been stabilized and the pressure source removed, the pressure created must be maintained for at least one hour.
The pressure created in the interstitial space of the tank must be released before the pressure of the inner wall.
During each test period, the necessary inspections must be made to ensure the tests are properly conducted and to prevent accidents.
O.C. 220-2007, s. 1; O.C. 87-2018, s. 251.