Who is licensed to work on gas lines in Ontario?

In Ontario, gas line work must be performed by contractors and technicians licensed by the Technical Standards and Safety Authority (TSSA) under the Gas Technology Act. Licensed gas technicians hold a G1, G2, or G3 certificate, depending on the type and pressure of gas systems they are qualified to work on. G2 is the most common commercial and residential gas technician qualification. Unlicensed gas work is illegal in Ontario and poses serious safety risks.

Do gas line installations require a permit in Ontario?

Yes. All gas line installations, extensions, and major modifications in Ontario require a permit from the TSSA. The permit is obtained by the licensed gas contractor before work begins, and an inspection is required upon completion. Minor repairs and direct appliance connections may have different permit requirements — your licensed gas contractor can advise on whether a permit is required for your specific work.

What pipe materials are approved for gas lines in Ontario?

Common approved gas pipe materials for commercial applications in Ontario include Schedule 40 or Schedule 80 black steel pipe with threaded or welded joints, corrugated stainless steel tubing (CSST) where approved by the local authority having jurisdiction, and copper tubing for certain lower-pressure applications. PVC and other plastic pipes are not approved for natural gas in Ontario above-grade applications. Your licensed gas contractor will specify the appropriate material for your application.

How is a gas line pressure-tested in Ontario?

Gas line pressure testing in Ontario must be performed in accordance with CSA B149.1 requirements. The line is isolated, pressurized with air or nitrogen (not gas) to the required test pressure, and monitored for pressure drop over the required test duration. No pressure drop indicates a leak-free installation. The TSSA inspector verifies that pressure testing was performed and may witness the test. All test records must be retained.

What is the minimum gas pipe size for a commercial building in Ontario?

Gas pipe sizing in Ontario is determined by the total connected appliance load (in BTU/h or kW), the length of the piping run, and the allowable pressure drop specified for the system. CSA B149.1 includes sizing tables for common configurations. For commercial buildings with multiple high-input appliances (commercial cooking equipment, boilers, make-up air heaters), a mechanical engineer or licensed gas contractor performs a load calculation and sizes the service, meter, and distribution piping accordingly.

What should I do if I smell gas in my Ontario building?

If you smell gas in your building: do not operate any electrical switches or devices; evacuate the building immediately; do not use elevators; call 911 from outside the building; and call Enbridge Gas (for natural gas) or your propane supplier's emergency line. Do not re-enter the building until emergency responders have cleared it as safe. Do not attempt to locate or repair the leak yourself.

Can I connect my own gas appliance in Ontario?

In Ontario, connecting a gas appliance to an existing gas line — even plugging in a pre-connected unit — requires a licensed gas technician to perform and certify the connection in most situations. This includes replacing a gas range, furnace, water heater, or commercial cooking appliance. A licensed technician verifies the connection, leak-tests the appliance connection, and ensures the venting is correct before the appliance is placed in service.

Gas Line Plumbing Ontario: Permits & Safety

Q: What standard governs gas line installation in Ontario?

CSA B149.1 (Natural Gas and Propane Installation Code) governs gas line installation in Ontario. This standard covers pipe materials, sizing, jointing, support, pressure testing, venting, and appliance connections. TSSA enforces compliance with CSA B149.1 in Ontario. The Ontario Building Code also references CSA B149.1 for gas work within the scope of building construction.

Contractors and technicians licensed by TSSA under the Gas Technology Act. G1 is unrestricted; G2 covers most commercial and residential gas work (systems up to 140 kPa). Unlicensed gas work is illegal in Ontario.

Yes — all gas line installations, extensions, and modifications require a TSSA permit before work begins. The permit is obtained by the licensed gas contractor, and a TSSA inspector must inspect completed work before the system is placed in service.

CSA B149.1 (Natural Gas and Propane Installation Code), enforced by TSSA. It covers pipe materials, sizing, jointing, support, pressure testing, venting, and appliance connections.

Schedule 40/80 black steel pipe (threaded or welded), CSST where approved, and yellow PE pipe for underground exterior service. PVC and other plastics are not approved for natural gas above-grade applications.

The line is isolated, pressurized with air or nitrogen (not gas) to the required test pressure, and monitored for pressure drop. No pressure drop indicates a leak-free installation. TSSA inspectors verify pressure testing was performed.

Sizing is determined by total connected appliance load (BTU/h), pipe length, and allowable pressure drop per CSA B149.1 sizing tables. A licensed gas contractor or mechanical engineer performs the load calculation for commercial buildings with multiple high-input appliances.

Do not operate electrical switches. Evacuate immediately. Call 911 from outside. Call Enbridge Gas emergency line. Do not re-enter until emergency responders clear the building. Never attempt to locate or repair a gas leak yourself.

No — connecting a gas appliance in Ontario requires a licensed gas technician to perform and certify the connection, verify venting, and leak-test the appliance connection before it is placed in service.

Book a Free Assessment — Licensed & Insured

Frequently Asked Questions

Gas Line Plumbing Ontario: Permits & Safety

Licensed Gas Line Work Across Ontario