Anthony — TSSA-Certified G1 Gas Technician
TSSA G1 licence #TBD · 15+ years in gas and mechanical trades · Service area: Greater Toronto Area, Ontario
Last updated: 2026-09-01
What gets a commercial kitchen red tagged?
Most commercial kitchen tags trace back to airflow, not to the appliance itself. Cooking equipment, the exhaust hood and the makeup air unit are one system, and when the balance between them breaks, the gas appliances are what fails the test.
The recurring causes are a makeup air interlock that no longer proves, a hood and exhaust arrangement that pulls more air than the space can replace, spillage under negative pressure, gas piping added or re-routed during a renovation without inspection, missing or improper shut-off valves at individual appliances, and clearance to combustibles lost when the line was rearranged.
| Cause | What the inspector sees | Typical fix |
|---|---|---|
| Makeup air interlock failure | Exhaust fan runs with no proven makeup air | Interlock repair or control rework, then retest |
| Negative pressure spillage | Flue gas rolling out of a draft hood under full exhaust | Rebalance air, correct makeup air capacity |
| Post-renovation gas piping | Uninspected piping, wrong sizing, unsupported runs | Piping corrected, pressure and leak tested |
| Missing appliance shut-off valve | No accessible manual valve at the appliance | Valve installed, usually same visit |
| Clearance to combustibles | Equipment too close to a wall, shelf or storage | Relocate, shield, or correct the surface |
Why does the makeup air unit cause so many tags?
Because it is the part of the kitchen nobody looks at until it stops proving. The exhaust hood removes a large volume of air. The makeup air unit is supposed to replace it. When it does not — a failed interlock, a burnt motor, a dirty filter bank, a unit undersized after a hood upgrade — the kitchen goes negative.
Under negative pressure, any atmospherically vented appliance in the building can spill. That includes the water heater in the back room and the booster heater under the dish line, which is why a hood problem often produces a tag on equipment nowhere near the hood.
Correcting these tags is usually a matter of restoring the interlock and the air balance, then re-testing every affected appliance under worst-case conditions with the exhaust at full speed.
What does a health or fire inspection add to this?
A gas tag is about combustion safety. A health inspection is about food safety and a fire inspection is about suppression, clearances and egress. They are separate processes, but they look at the same physical space and they routinely find each other's problems.
In practice, a fire inspection that flags a hood suppression or clearance issue often surfaces a gas defect at the same time, and a gas correction that requires moving equipment can pull the hood, the suppression nozzles and the clearances back into scope. Plan corrections together rather than in sequence — it is faster and it avoids a second closure.
Red Tag Relief handles the gas side and coordinates the trades that handle the rest. We are not a health or fire authority and do not act on behalf of one.
How fast can a tagged kitchen reopen?
Valve, clearance, and interlock corrections are frequently same-day. Piping rework after a renovation takes longer because the corrected work has to be pressure and leak tested before anything is returned to service.
Equipment replacement — a cracked section, a failed heat exchanger on a rooftop unit serving the dining room — depends on parts. Where only some appliances are affected, partial reopening is often possible: the defective appliance is isolated and documented, the rest of the line is returned to service.
Tell us which stations are down and what your service hours are. That is what determines the sequence.
Frequently asked questions
Can I keep cooking on the appliances that were not tagged?
Sometimes. If the defect is isolated to one appliance and the rest pass testing under worst-case conditions, the untagged equipment can stay in service. If the tag is on the makeup air or venting system, it usually affects everything connected to it.
Who can clear a red tag on commercial kitchen equipment?
A TSSA-certified gas technician. Above 400,000 BTU/h input the work requires a G1. Most commercial ranges, fryers and makeup air units in a full kitchen sit above the G2 limit once totalled on a common gas train.
Do you attend outside service hours?
Yes. Corrections in an operating kitchen are often scheduled before opening or after close so the room is empty and the exhaust can be run at full speed for testing.
Will I get documentation for my landlord or insurer?
Yes. Every cleared tag comes with a written correction record naming the defect, the correction, and the verification results.