Pneumatic pressure testing requirements

This page explains pneumatic pressure testing requirements on highway and portable tanks. These tests are required by CSA B620.


This page does not change, create, or alter the Transportation of Dangerous Goods (TDG) Regulations.

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Pressure testing methods

All highway tanks and TC portable tanks used in the transportation of dangerous goods are required to be pressure tested at periodic intervals in accordance with CSA B620. When performing a pressure test, in accordance with Clause 7.2.7 Pressure tests of CSA B620, tank testers have the option of performing this test through two methods:

  • a hydrostatic test (Clause
  • a pneumatic test (Clause

Hydrostatic pressure test

Hydrostatic pressure testing is the preferred method for pressure testing in accordance with CSA B620. This method of pressure testing presents a lower safety risk than pneumatic testing, due to the smaller amount of potential energy stored during the test.

Pneumatic pressure test

Important notice

The energy stored by pressurized air or other gas during pneumatic testing can result in severe damage and personal injury in the event of tank or component failure. The risk associated with the use of air or other gas as the test medium (pneumatic testing) is much higher than the risk associated with the use of a liquid (hydrostatic testing).

A pneumatic pressure test is inherently more hazardous than a hydrostatic pressure test of the same volume, pressure, and temperature. With failures, the sudden release of energy is catastrophic and the effects are comparable to those of an explosion.

Facilities and tank testers using a pneumatic test as the method of performing the pressure test must meet the requirements of Clause of CSA B620, seen below. The pneumatic test shall be used only where

  1. there is no suspicion of weakness in the tank; and
  2. the presence of residual water in the tank after the hydrostatic test would
    1. react with the lading or the tank or any lading retention component; or
    2. result in the formation of ice, causing damage or adversely affecting the proper functioning of the tank.

Important notice

Either the condition from OR of CSA B620 must be fulfilled. Otherwise, pneumatic testing is not permitted.

Examples of acceptable situations in which a pneumatic pressure test can be performed

Acceptable situation according to Clause (a)(ii)(1) of CSA B620:

  • transporting UN 1829 sulfur trioxide, stabilized, can cause dangerous vapours to form when it comes into contact with water

Acceptable situation according to Clause (a)(ii)(2) of CSA B620:

  • residual water from a hydrostatic test could form ice when a TC 341 returns to service and filled with liquid nitrogen

The ease of execution and the low financial cost are not acceptable justifications to perform a pneumatic pressure test.

Anyone who’s registered with Transport Canada to perform pneumatic testing on TC 406 highway tanks can continue to do so as long as the requirements of Clause (a) of CSA B620 are met.

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