Field Approval Program

The TSSA Field Approval Program approves custom-made appliances that cannot be certified by designated certification organizations.

In Ontario, every appliance fueled by natural gas, propane, digester, landfill, biogas or other fuels and is offered for sale, sold, rented, bought or installed must be approved under the Technical Standards and Safety Act, 2000. 

The Technical Standards and Safety Authority (TSSA) Field Approval Program is an approval process for custom-made appliances that are limited in numbers and cannot be certified by designated certification organizations. The usual certification process will continue to apply to regular appliances, equipment and all components and must be certified by the Standards Council of Canada (SCC) accredited testing organizations before they can be used. 

How Field Approval works

Field Approval is used for approval of fuel features of appliances or equipment. Fuel features are components that use a fuel, handle a fuel, control combustion or vent combustion products, or features of construction and installation that relate to the safe use and handling of a fuel. In general, this means gas supply piping and valves, an appliance itself, and its venting system.

TSSA Field Approval includes installation. Except for portable appliances, it is valid only for the site where the appliance is installed. Appliances with Field Approval that are relocated will have to be re-approved in their new location.

Reviewing or verifying the production performance of the appliance being approved is not covered under this program.

You may proceed with installing and testing an appliance once you apply to TSSA for Field Approval, although modifications may be required as a result of our review. As a reminder, installation and testing may only be conducted by an appropriate certificate holder. 

You may NOT operate an appliance until a TSSA Field Approval label is affixed to the appliance; it is illegal to operate an appliance before it is approved.

Note: approval under this program does not include approval of the electrical features of appliances, equipment or components that require approval under Ontario’s Electricity Act, 1998 and the Ontario Electrical Safety Code. Evidence of the electrical approval is required before TSSA’s Field Approval can be granted. This approval must be for the entire appliance, including its control panel(s) and the wiring to and from the panel(s). Please visit the Electrical Safety Authority to request an up-to-date list of electrical approval agencies.

How to obtain Field Approval

Submit an Application for Field Approval of Appliances or Equipment (pdf) to TSSA, along with the required documentation and the deposit fee listed on the form. Your submission will be reviewed once TSSA receives your application and the deposit fee.

Submit your application at least two months before the date you need an inspection. TSSA offers, on a case-by-case basis, expedited engineering services. Processing time is not guaranteed and is reliant upon the completeness and quality of the submission. To request expedited engineering services, please indicate this on your application form and select "Expedited" when submitting via the Portal. 

A separate application and fee must be submitted for each address at which an appliance, equipment or a component requiring approval is going to be installed. 

Required documentation

Documentation must be submitted with the application. Documentation must include the following:

  • Completed Field Approval application.
  • Electrical schematic in a ladder diagram format.
  • Valve train diagram 
  • Bill of materials for all fuel features, and 
  • Purge calculation

If you have it, the following information will help us review your application and, thus, will lower the review costs:

  • Completed Field Approval Submission Summary (pdf). 

  • Description of the appliance, equipment or component.

  • Installation and operating instructions.

  • Sequence of operation 

  • Literature on valve train components and controls

  • Any other documents which may facilitate the review of the application

All electronically submitted documents must be in PDF format.

When we receive your application and the deposit fee, we will review your submission to make sure that it is complete. If additional information is required, it will be requested from the applicant and the application will be kept open pending receipt of the information requested. 

Subsequent review will consist of a detailed examination of the appliance’s fuel features. When this review is completed, we will advise the applicant to contact a local inspector to arrange for appliance inspection and testing.


For further fee information and an up-to-date fee schedule, please visit our Fees page.

Site inspections

A TSSA site inspection will verify that:

  • Your appliance or equipment is constructed according to the submitted documentation. 
  • Your appliance or equipment is installed in accordance with the applicable code and the manufacturer’s instructions. 
  • The fuel features of your appliance or equipment: 
    • Perform the required functions,  
    • Are set in accordance with the applicable code/standard,  
    • Are operating within their certified specifications,  
    • Use certified or approved components, and  
    • Comply with approved standards/codes. 
  • Your appliance or equipment and its components comply with approved codes and/or standards.

The inspector may require that the appliance or equipment is tested to verify it operates properly. In most cases it will be necessary for the person responsible for initially activating the appliance to be present during the site inspection and to have the necessary test equipment. This person must be an appropriate certificate holder for that purpose.

Upon successful completion of site examination and testing, the inspector will issue a written confirmation of the appliance approval under this program to the applicant’s representative present on the site.

Field Approval Label

When site inspection and testing is completed, the inspector will place the TSSA Field Approval label on the appliance rating plate.

 An example label is shown below:

 Field Approval FSD-00000 Mark

If an appliance does not have a rating plate supplied by the manufacturer, or if the manufacturer’s rating plate does not contain the required information, it will be the applicant’s responsibility to supply a rating plate with the required information and attach this rating plate to the appliance.

The rating plate shall contain the information required in the applicable appliance standard or in the absence of such standard, it shall contain the information specified in Section 2.1.27 of the TSSA Field Approval Code: TSSA-FA-2020 code.  Custom rating plates shall contain approximately 2" x 2" space for the TSSA field approval label.

More information

For more information, please contact TSSA’s Fuels Safety Program at (416) 734-3348 or toll-free at (877) 682-8772, or email

View the following documents for additional information on TSSA Field Approval: