Gas work is the most tightly controlled trade in Canada because of the fire and explosion risk, and every province licenses the gasfitter who does it. Most provinces split the work into two classes by appliance size: a lower class for residential and light commercial appliances up to 400,000 BTU per hour (about 120 kilowatts), and a higher class for everything above that, including large commercial and industrial systems. Ontario is the odd one out, using a three-tier TSSA gas technician system (G1, G2 and G3) instead of A and B classes. The certifying authority changes at every border, and gas fitting is a separate trade from plumbing almost everywhere, so a plumbing ticket does not carry gas rights.
The Class A / Class B model (most provinces)
In British Columbia, Alberta, Manitoba, Saskatchewan and across most of the country, gasfitter certification comes in two classes:
- Class B (the residential and light-commercial ticket): appliances and systems up to 400,000 BTU per hour. This is the standard ticket for furnaces, boilers, water heaters and fireplaces in homes and small commercial premises.
- Class A (the unrestricted ticket): all Class B work plus large commercial and industrial appliances over 400,000 BTU per hour. In BC, Class A is unlimited input except vehicle fuel systems. Alberta's Class A trades-qualifier route requires 54 months and 7,020 hours, including at least 1,000 hours on appliances over 400,000 BTU per hour.
Ontario: the TSSA G1, G2 and G3 system
Ontario regulates gas under the Technical Standards and Safety Authority (TSSA), with three certificates under Ontario Regulation 215/01. The important point, often stated wrongly, is how the boundary works:
- G3: the entry certificate. A G3 may work on piping under 2.5 inches up to the appliance control valve, reactivate previously installed appliances, and do cleaning and vent work, but only under at least general supervision, and a G3 may not perform the initial activation of a new appliance. G3 is not an "appliance connections only" ticket.
- G2: covers any natural gas or propane appliance up to 400,000 BTU per hour independently. G3 and G2 share that 400,000 BTU per hour ceiling; the practical difference is that G2 works without supervision and G3 does not.
- G1: adds the over-400,000 BTU per hour work, with no input ceiling, and may supervise G2 and G3 holders. G1 requires a valid G2, 4,000 hours of G2 field experience (at least 500 of them on systems over 400,000 BTU per hour under G1 supervision), and a 75 percent exam pass.
A company doing gas work for hire in Ontario must also hold a TSSA Registered Fuels Contractor registration; the individual technician still needs their own G1, G2 or G3.
Who certifies the gasfitter, province by province
- Ontario: TSSA certifies the technician (G1/G2/G3) and registers the fuels contractor.
- British Columbia: SkilledTradesBC issues the Certificate of Qualification (Class A and Class B are compulsory trades since 1 December 2023, and Class B became a Red Seal trade on 1 January 2025); Technical Safety BC issues its own certificate via the ARD exam and licenses the gas contractor.
- Alberta: gasfitter Class A and Class B are compulsory trades certified through Skilled Trades Alberta, under the Safety Codes Act.
- Saskatchewan: the Saskatchewan Apprenticeship and Trade Certification Commission (SATCC) runs the exams; the Technical Safety Authority of Saskatchewan (TSASK) issues the licence. Saskatchewan uses a Domestic Gasfitter and a General Gasfitter pathway, and a journeyperson plumber can add the Domestic Gasfitter licence by exam.
- Manitoba: Inspection and Technical Services (ITS), part of Manitoba Labour and Immigration, issues gasfitter licences (Class A and Class B). A Red Seal endorsement is required to supervise apprentices as of 31 December 2025.
- Nova Scotia: the Department of Labour, Skills and Immigration (Technical Safety Division) regulates gas under the Technical Safety Act; technicians complete the Gas Fitter Red Seal apprenticeship through the Nova Scotia Apprenticeship Agency, and a business needs a Gas Business Licence.
- New Brunswick: Technical Inspection Services (Department of Public Safety) regulates gas; a Gas Installation Contractor Licence is required to pull a gas permit.
- Newfoundland and Labrador: Engineering and Inspection Services (Service NL) licenses gasfitters under the boiler, pressure vessel and compressed gas regulations.
- Quebec: gas work falls under RBQ specialised subclasses managed by the CMMTQ (see below), with a CCQ competency card for workers on covered sites.
Quebec: the CMMTQ-reserved subclasses
Quebec does not issue a simple gasfitter ticket. Gas and heating work is reserved to licensed masters through CMMTQ-exclusive RBQ subclasses: 15.1 (forced-air heating), 15.2 (natural gas burner systems), 15.3 (oil burner systems) and 15.4 (hydronic heating), plus 15.5 (plumbing). A general RBQ contractor cannot do natural gas burner work without holding subclass 15.2 or subcontracting to a CMMTQ master who does. Gas fitter certification is compulsory in Quebec.
A real blind spot: the gasfitter Red Seal
Gas fitting is a Red Seal trade in several provinces, but a gasfitter Red Seal endorsement is not recognised in Ontario or Saskatchewan. A tradesperson who earned gas tickets in a Red Seal province can wrongly assume the endorsement carries everywhere. For gas, it does not. Check the destination province's specific recognition rules (see Trade Reciprocity Between Provinces).
Common mistakes
- Assuming a plumbing ticket includes gas. Gas fitting is a separate trade almost everywhere; the exception is Saskatchewan, where a plumber can add a Domestic Gasfitter licence by exam.
- Reading G3 as "connections only". G2 and G3 share the up-to-400,000 BTU per hour ceiling; G3 simply needs supervision and cannot first-activate a new appliance.
- Expecting the gasfitter Red Seal to carry into Ontario or Saskatchewan. It is not recognised there.
- Forgetting the contractor layer. In Ontario and BC a business needs a separate fuels or gas contractor registration on top of the individual ticket.
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