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Ontario gas technicians must follow more than the national CSA B149.1 codebook. They must also apply the Ontario-specific requirements contained in the Technical Standards and Safety Authority’s Gaseous Fuels Code Adoption Document.
TSSA published the new Gaseous Fuels Code Adoption Document Amendment FS-279-26 on April 2, 2026. It became effective on June 1, 2026, replacing the previous FS-225-21 document dated May 1, 2021. The new document is 58 pages long and introduces updated national codes together with Ontario-specific amendments.
This article provides a practical overview of what the new document means for gas technicians working in Ontario.
Important: This article is an educational summary. Always consult the current TSSA document, the applicable CSA code, Ontario regulations, manufacturer-certified instructions, and official TSSA interpretations before performing regulated gas work.
What is a Code Adoption Document?
A Code Adoption Document, commonly called a CAD, is the document TSSA uses to adopt national codes and apply Ontario-specific changes.
The national CSA code gives the general technical requirements. The Ontario CAD can:
- Replace a clause
- Revoke a clause
- Add a new requirement
- Change a definition
- Make an informative annex mandatory
- Add Ontario inspection, notification or documentation procedures
Where the CAD conflicts with a referenced code or standard, the Ontario CAD states that its requirements prevail. Consequently, using B149.1 without checking the Ontario amendments can leave an otherwise competent technician following the wrong requirement.
Which codes were adopted in 2026?
The 2026 Gaseous Fuels CAD adopts five major standards or code sections.
1. CSA B149.1:25
The Natural Gas and Propane Installation Code covers the installation of appliances, piping, tubing, venting systems, combustion air and related gas equipment.
Ontario adopts the 2025 edition with provincial amendments.
2. CSA B149.3:25
The Code for the Field Approval of Fuel-Related Components on Appliances and Equipment applies to equipment that requires field approval, including certain custom-built, site-built or limited-production appliances.
3. CSA B149.3 Annex J
Annex J contains requirements for Mobile Food Service Equipment, including food trucks, trailers and certain portable food carts.
It replaces the former standalone TSSA Mobile Food Service Equipment Code.
4. CSA B149.6:25
The Code for Biogas Generation and Utilization applies to the storage, handling and use of biogas systems.
It replaces the previous TSSA Digester, Landfill and Biogas Code.
5. NFPA 160:2021
NFPA 160 covers flame effects used before an audience, including certain entertainment, performance and film applications.
Each adopted standard is subject to the Ontario amendments written into the CAD.
Important B149.1 changes for Ontario gas technicians
The first section of the CAD contains Ontario amendments to CSA B149.1:25. This section is likely to affect the largest number of residential and commercial gas technicians.
Manufacturer instructions versus the gas code
Ontario replaces Clause 4.1.5.
Where the manufacturer’s certified installation instructions conflict with the code, the technician must follow whichever requirement is more stringent.
This means the technician cannot automatically choose the code requirement because it is more convenient, nor can the technician blindly choose the manufacturer’s instructions. Both documents must be reviewed and the more restrictive safety requirement applied.
Practical example
Suppose the gas code permits a certain minimum clearance, but the certified appliance instructions require a greater clearance.
The greater manufacturer-required clearance applies.
If the code imposes a more restrictive requirement than the instructions, the code requirement applies.
Appliance assembly and field approval
Ontario also replaces Clause 4.2.3.
The assembly or construction of an appliance is regulated by the authority having jurisdiction and must comply with Section 2 of the Ontario CAD concerning field approval.
This can apply to:
- Custom-built appliances
- Appliances assembled at the installation site
- Equipment produced in limited quantities
- Imported equipment without acceptable certification
- Major changes to previously approved equipment
- Modified burner or fuel-control systems
The field-approval section states that approval applies to the appliance at its approved location. It also states that modification can void the approval, requiring the modified appliance to be approved again. Apparently, attaching an assortment of certified components does not magically create one certified appliance.
Mandatory residential boiler safety checks
The CAD contains mandatory safety-check requirements for certain residential natural-draft boilers.
During the heating season, identified as October 15 through April 30, a certified G1, G2, G3 or GUT technician entering a one- or two-family residential building for service, maintenance or emergency work must determine whether the building contains a natural-draft boiler:
- Equipped with a draft-control device
- Rated at 300,000 Btu/h or less
- Without a valid applicable inspection label
Where the requirement applies, the technician must perform the prescribed inspection process. This includes providing the owner information sheet, taking a flue-gas carbon monoxide reading and checking for evidence of unsafe operation or spillage.
The CAD specifies action when the measured flue-gas carbon monoxide exceeds the prescribed limit. Technicians should read the complete procedure rather than relying on a summary, particularly because notification, shutdown, corrective-action and labelling requirements may apply.
Existing outdoor B-vent requirements
The CAD addresses existing B-vent systems that were not certified for exterior use but were installed outdoors.
Where such a vent is identified as an unacceptable condition without an immediate hazard, continued use beyond the normal correction period is allowed only when all prescribed conditions are satisfied.
These conditions include:
- Written notification to the owner or user
- Notification to the fuel distributor
- Confirmation that the vent is operating safely
- An equipment notice or tag
- Annual inspections arranged by the owner
- Continued documentation of the inspections
If the requirements are not maintained, the non-compliant vent must be replaced with a current code-compliant venting system. Replacement is also required when an affected appliance is replaced, removed or newly installed under the conditions described in the CAD.
Annex G is mandatory in Ontario
The new CAD adopts Annex G of CSA B149.1 as normative, meaning mandatory rather than merely informative.
This distinction is easy to overlook. Annexes are often treated as explanatory material, but a normative annex forms part of the enforceable requirements. Gas technicians should therefore review Annex G as an operative part of the Ontario installation requirements.
The CAD also incorporates four Ontario annexes:
- Annex P: Installation of piping or tubing in rocky areas
- Annex Q: Residential natural-draft boiler safety checks
- Annex R: Existing uncertified outdoor B-vent procedures
- Annex S: Mobile food service equipment labels and annual inspection certificate
Field approval requirements
Section 2 of the CAD covers appliances that are custom-made, built on-site or produced in limited numbers.
A field-approval application may require documentation such as:
- A description of the appliance or process
- Electrical schematics
- Valve-train or combustion diagrams
- Piping and instrumentation diagrams
- A bill of materials
- Safety-ventilation calculations
- Explosion-relief calculations
- Professional engineer review for certain programmable flame-safety systems
- Functional logic and power-distribution drawings
Technicians involved with industrial burners, process equipment and custom gas trains should review this section before construction or modification begins. Trying to arrange approval after the machine has been built is the regulatory equivalent of checking the map after driving into a lake.
Mobile Food Service Equipment requirements
Section 3 adopts CSA B149.3 Annex J with Ontario amendments for Mobile Food Service Equipment.
MFSE can include:
- Food trucks
- Vans fitted with fuel-fired food equipment
- Towable food trailers
- Portable food-service carts
- Equipment with propane-fired cooking, water heating or power generation
The requirements address cylinder protection, enclosures, piping, regulators, ventilation, generators, appliance installation, inspection labels and annual inspection documentation.
The CAD requires annual inspection documentation to remain with the mobile unit until the following inspection. TSSA may also inspect the equipment to confirm that its annual inspection is current.
Technicians servicing festival vendors, food trucks or mobile kitchens should not treat these units like ordinary stationary restaurant installations.
Biogas systems
Section 4 adopts CSA B149.6:25 with Ontario amendments.
The code applies to the storage, handling and use of biogas. It can affect wastewater treatment, organic digestion, landfill gas and related systems.
Ontario’s amendments include requirements concerning:
- Qualified personnel
- Shut-off and test-firing valves
- Blowers and compressors
- Hazardous electrical locations
- High-performance butterfly valves
- Documentation and control systems
The CAD also clarifies that treated renewable natural gas meeting the receiving utility’s pipeline specifications is excluded from the B149.6 application described in that section.
Most residential technicians will rarely encounter this section, but industrial and institutional technicians should know that it exists.
Flame effects before an audience
Section 5 adopts NFPA 160:2021 with Ontario amendments.
It covers fuel-fired flame effects used in applications such as:
- Live performances
- Film production
- Entertainment venues
- Special events
- Theatrical productions
The Ontario amendments include operator-training requirements, cylinder requirements, control-system provisions and field-approval conditions.
This is specialized work and should not be confused with installing an ordinary decorative gas appliance.
How technicians should use the new CAD
Gas technicians should not read the CAD once and then throw it into the traditional service-van archaeological layer beneath old fittings and coffee cups.
Use the following process on regulated work:
- Identify the appliance, fuel and type of installation.
- Locate the applicable requirement in the national CSA code.
- Search the Ontario CAD for the same clause or subject.
- Review the manufacturer’s certified instructions.
- Apply the most stringent applicable requirement.
- Check for TSSA directives, safety orders, advisories and regulatory requirements.
- Document measurements, inspections, notices and corrective actions.
Does the CAD replace CSA B149.1?
No.
The CAD adopts CSA B149.1 and modifies specific parts of it. A technician generally needs both documents:
- The current CSA B149.1 code
- The current Ontario Gaseous Fuels CAD
The CAD does not reproduce every requirement found in the national code.
Is the previous 2021 CAD still valid?
The new CAD superseded FS-225-21 on June 1, 2026. Work performed after the effective date must be evaluated using the currently adopted requirements, subject to any applicable transitional or official regulatory direction.
Does the Gaseous Fuels CAD cover all propane requirements?
Not by itself.
The Gaseous Fuels CAD is adopted under Ontario Regulation 212/01. Propane storage and handling are also subject to Ontario Regulation 211/01 and the separate Ontario Propane Code Adoption Document. Technicians working with propane must identify every applicable regulation and code rather than relying on one document with a reassuringly official cover page.
Final takeaway
The Ontario Gaseous Fuels CAD is not an optional companion to CSA B149.1. It contains enforceable Ontario amendments that can change how a national clause is applied.
The 2026 edition introduces updated requirements for:
- Natural gas and propane installations
- Appliance field approval
- Mobile food service equipment
- Biogas systems
- Flame effects
- Residential boiler safety checks
- Existing outdoor B-vent systems
Every Ontario gas technician should keep access to the latest CAD and consult it whenever reviewing an installation, performing service work or applying a CSA B149 requirement.