New requirements for nurse tanks transporting anhydrous ammonia in Canada


This bulletin includes important information about TC 51 tanks, nurse tanks and changes to CSA B620:20 and B622:20 standards.


This page does not change the Transportation of Dangerous Goods (TDG) Regulations.


This bulletin is for anyone who works with highway tanks, nurse tanks or TC portable tanks for transporting anhydrous ammonia for agricultural purposes.

What you need to know

Anhydrous ammonia is classified by the Transportation of Dangerous Goods Regulations as a class 2 dangerous good. Some farmers apply anhydrous ammonia to their fields as a liquid fertilizer to improve crop yields.

TC 51 nurse tanks

Farmers can apply anhydrous ammonia to their fields using nurse wagons, pulled behind a tractor. Some of these nurse wagons consist of multiple inter-connected tanks, while newer wagons consist of larger single tank installed on a wagon. These are all considered as nurse tanks.

The Canadian Standards Association has recently made changes to CSA B620:20 and CSA B622:20. They’ve reintroduced TC 51 specification tanks and include them in the definition as nurse tanks in CSA B620:20. Going forward, TC 51 specification tanks will be the main tank used as nurse tanks for anhydrous ammonia in agricultural service per CSA B622:20.

TC 51 tanks and CSA B620

CSA B620-14 didn’t include construction requirements for TC 51 tanks. This is because construction of these tanks was believed to not be needed, since other tank options are available.

Even though they do not exist in the current B620-14 standard, the Transportation of Dangerous Goods Regulations still allows for TC 51 tanks to be manufactured according to CSA B620-09.

However, the CSA B620 Technical Committee decided that these tanks are important for agriculture and propane services, so they added the TC 51 specification back into CSA B620:20.

Changes to portable and nurse tanks requirements

CSA B622:20 now includes mounting requirements for all portable tanks secured to a vehicle or trailer. A professional engineer will need to verify that the tank mounting and rear-end protection follow CSA B620. This will apply to all portable tanks, except existing nurse tanks (non-specification ASME tanks allowed for anhydrous ammonia use according to CSA B622).

A CSA B620 registered design engineer must certify new TC 51 nurse tank piping when connected after the first manual shut-off valve. The piping must also be installed by a CSA B620 registered facility. The tank owner must keep all records of this certification.

There is also a new requirement for an emergency discharge control for interconnected nurse tanks or any nurse tank that can hold 10,000 litres or more. This requirement will be phased in, but will be in force starting on January 1, 2022.

Nurse tanks will not need a remote emergency shutoff system as required for TC 51 tanks, but can use a remote method for closing tank valves that is operated from the tractor instead. A passive emergency shutdown system is also required when using this method.

The Canadian Standards Association has deleted the specific requirement (SR) 73 of CSA B622-14, for anhydrous ammonia tanks mounted on skid packages for agricultural use. Special permissions for anhydrous ammonia will only be listed in SR 54 and SR 55 of CSA B622.

All nurse tanks will be required to undergo an annual leakage test per CSA B620:20. Existing registered facilities that inspect and test nurse tanks that want to add leakage test to their current registration must submit a request to Engineering Services.

Applying to perform leak tests

If you would like to perform leakage testing of nurse tanks and are not registered to do so, please contact us.

When applying to add leakage testing to your registration, your email to the Engineering Services group must include:

  • a statement that you want to add leakage testing of nurse tanks to your scope of work;
  • your facility registration number (i.e., 25-xxxx);
  • the leakage test procedure present in your quality control manual, as per Clause 7.2.5 of CSA B620; and
  • a sample leakage test report required as per Clause 7.3 of CSA B620.

Important notice:

Only send the documents requested above with your application. Please don’t send a new application form or a copy of your quality control manual.


If you have any questions, please contact our Regulatory Frameworks and International Engagement Branch:

Phone: 1-855-298-1520 (toll free)