TSSA Gas Technician 3 (G3) flashcards
TSSA Gas Technician 3 (G3) · Build recall with a focused review session.
32 cards. Read the term and the definition here. The deck at the top of this page is optional.
- Heating value of natural gas
- Natural gas, mostly methane, delivers roughly 37-38 MJ/m3 (about 1,000 BTU/ft3) as supplied by Ontario utilities; appliance input ratings assume this value.
- Propane relative density
- Propane is about 1.5-1.7 times heavier than air and settles in low areas; natural gas is lighter than air and rises when released.
- Complete combustion equation
- Methane plus oxygen yields carbon dioxide and water: CH4 + 2O2 -> CO2 + 2H2O. Insufficient oxygen produces carbon monoxide instead.
- Stoichiometric air requirement
- Perfect combustion of natural gas needs about 10 volumes of air per volume of gas; practical systems supply excess air to ensure complete combustion.
- Combustion triangle
- Fuel, oxygen and an ignition source are required for combustion; removing any one of the three prevents or extinguishes burning.
- Yellow flame tip cause
- A yellow-tipped flame usually indicates insufficient primary air or a dirty burner; a lifting flame suggests excess primary air or excessive gas pressure.
- Water column conversion
- One inch of water column equals 0.249 kPa; one psi equals 27.7 in. w.c. or 6.895 kPa. Manifold pressure for natural gas is often 3.5 in. w.c.
- Odorant in natural gas
- Mercaptan odorant is added so leaks can be detected by smell; the smell is a safety warning and does not indicate concentration.
- Ontario gas regulation
- The Technical Standards and Safety Act and the Gas Utilization Code regulate gas work in Ontario; TSSA administers licensing and enforcement.
- G3 scope of work
- A G3 certificate holder works only under supervision; independent work on gas appliances and piping requires a G2 or G1 certificate.
- Approved leak detection
- Leaks are located with soap solution or an approved electronic detector, never an open flame; new piping is pressure-tested with air or inert gas.
- Gas leak emergency response
- Evacuate, remove ignition sources, avoid operating electrical switches, and call the gas distributor and emergency services from a safe location.
- CO alarm requirement
- Dwellings with fuel-burning appliances or attached garages require carbon monoxide alarms under the Ontario Fire Code, installed per manufacturer instructions.
- Draft hood spillage meaning
- Spillage of flue gases at a draft hood signals a venting or combustion air problem and must be corrected before the appliance is returned to service.
- Approved piping materials
- Black steel pipe, corrugated stainless steel tubing and copper tubing are used where the Code permits; copper is restricted in some concealed or corrosive locations.
- Equivalent length sizing
- Pipe sizing uses total load and equivalent length; each fitting, such as a 90-degree elbow, adds equivalent straight-pipe length to the run.
- Threaded joint sealing
- Approved pipe dope or PTFE tape is applied to male threads only when joining steel gas pipe; excess sealant inside the pipe can block orifices.
- Sediment trap purpose
- A drip leg installed at the appliance inlet as a capped tee catches debris and moisture before it reaches the gas valve or burners.
- Appliance shut-off valve
- A manual shut-off valve is installed upstream of each appliance, kept accessible and identified, with a union or approved disconnect for servicing.
- Piping pressure test
- New or altered gas piping is tested with air or inert gas at Code-specified pressure and duration, then purged of air before gas is introduced.
- CSST bonding requirement
- Corrugated stainless steel tubing must be bonded and installed with manufacturer-approved fittings per Code requirements to reduce lightning-related arc risk.
- Category I appliance
- A Category I appliance is non-condensing and operates under negative pressure, venting into a vertical chimney or listed Type B vent.
- Category IV appliance
- A Category IV appliance is condensing and operates under positive pressure, requiring listed plastic venting such as PVC, CPVC or polypropylene per manufacturer instructions.
- Confined space combustion air
- Appliances in a confined space need permanent high and low openings sized by Code to total input; a single opening is allowed only under specific conditions.
- Direct-vent appliance
- A direct-vent or sealed combustion appliance draws combustion air from outdoors and vents outdoors, maintaining manufacturer clearances to openings and intakes.
- Vent termination clearance
- Vent terminals must keep Code and manufacturer minimum distances from windows, doors, air intakes, grade and adjacent buildings to prevent flue gas re-entry.
- Condensate trap requirement
- Condensing appliances drain acidic condensate through a trap to an approved location; a blocked or frozen drain can cause appliance lockout.
- Rating plate verification
- The rating plate gives input, manifold pressure and gas type; the appliance must match the supply, and propane conversion requires an approved kit.
- Manifold pressure check
- Manifold pressure is measured with a manometer at the appliance regulator; typical values are 3.5 in. w.c. for natural gas and 10-11 in. w.c. for propane, per rating plate.
- Load test of supply pressure
- Supply pressure is checked with all appliances operating; inlet pressure must stay within the appliance's specified range to prevent incomplete combustion or damage.
- Flue CO measurement
- Combustion analysis measures CO, CO2 and O2 in flue gases; flue CO above the manufacturer's limit indicates a combustion problem requiring correction.
- Thermocouple function
- A thermocouple generates millivolts when heated by the pilot flame; low output causes pilot dropout, so the thermocouple and flame sensor must be clean and properly positioned.