Transport Canada has released the following bulletin, Volumetric capacity on TC highway tanks, which covers important safety information about marking and filling highway tanks that transport dangerous goods. The bulletin is targeted to anyone who manufactures TC highway tanks and for those who fill these and other highway tanks with dangerous goods (DGs). While this does not immediately affect propane, some members may be affected for class 3 dangerous goods containers.
Transport Canada issued the bulletin after it found that some registered facilities have been incorrectly marking the volumetric capacity on the data plates of newly made TC highway tanks. These mistakes predominantly affected tanks designed to carry Class 3, 4, 5, 6.1, 8, and 9 DGs.
If the volumetric capacity on a metal identification plate is not marked correctly, the tanks can be accidentally overfilled, resulting in an unsafe tank level and a DG spill.
Individuals filling these dangerous goods tanks must comply with the filling requirements in CSA B621.
Plate marking requirements
The manufacturing requirements for TC highway tanks intended for DGs service are found in CSA B620-14.
From CSA B620-14, Clause 3, Terminology and definitions:
The volumetric capacity of a tank is NOT the maximum volume of product that can be loaded into the tank.
Filling requirements
The maximum amount of DGs that may be loaded into a tank carrying Class 3, 4, 5, 6.1, 8, and 9 DGs must be determined per Clause 7.3 of CSA B621-14.
7.3 Loading requirements
During loading of a means of containment...
(d) If the means of containment is a tank, the outage left in the tank shall:
(i) not be less than 2% of its volumetric capacity;
(ii) be sufficient to prevent the tank from becoming liquid-full should the temperature of the contents rise to 55 °C (131°F); and
(iii) if the tank is to be placed, stored, or parked within an enclosed space, be sufficient to prevent venting should the temperature of the contents rise to 55 °C (131°F).
A person loading TC highway tanks must ensure that these requirements are met when filling the highway tank. This will ensure that the tank cannot become liquid full while in transport. The filler will need to determine the maximum filling volume based on the volumetric capacity indicated on the metal identification plate, as defined in CSA B620-14.
For any questions, contact TC’s Regulatory Frameworks and International Engagement Branch: at MOCRegister-RegistreContenant@tc.gc.ca or 1-855-298-1520 (toll free).