Gas Installation Inspection

Per CSA B149.1 and provincial gas safety regulations, all gas installations require a permit from the provincial gas safety authority (e.g., TSSA in Ontario, TSASK in Saskatchewan). The gas piping system must be designed to deliver adequate gas volume at the required pressure to all appliances. Pipe sizing must account for total connected load, pipe length, and allowable pressure drop per CSA B149.1 sizing tables. Only licensed gas fitters may perform gas work.

1. Verify a valid gas installation permit has been obtained from the provincial gas safety authority

2. Confirm the gas fitter holds a valid licence for the class of work being performed

3. Review the piping layout drawing to confirm pipe sizing is adequate for the total connected BTU load per CSA B149.1 sizing tables

4. Verify the gas metre size and regulator capacity are sufficient for the total connected load

5. Check that the piping material is approved per CSA B149.1 (steel, copper, CSST, or PE for buried exterior)

- Gas work performed without a valid permit or by an unlicensed fitter

- Piping undersized for the total connected appliance load causing low pressure

- Gas metre or regulator capacity insufficient after additional appliances are added

- Unapproved piping materials used (e.g., galvanised pipe for concealed installations)

Per CSA B149.1, gas piping must be properly supported, protected from physical damage, and installed with approved fittings and jointing methods. Steel pipe must be joined with threaded fittings using approved thread sealant or welded by certified welders. CSST (corrugated stainless steel tubing) must be installed per the manufacturer's instructions and bonded per CSA B149.1. All piping must be sloped to prevent moisture traps and equipped with a sediment trap (drip leg) at each appliance connection.

1. Verify pipe supports are spaced per CSA B149.1 requirements (e.g., every 1.8 m for 20 mm steel pipe)

2. Confirm threaded joints use approved pipe thread sealant (not Teflon tape on flare fittings) and are properly tightened

3. Check that CSST is bonded to the building grounding electrode system per CSA B149.1 and manufacturer's requirements

4. Verify a sediment trap (drip leg) is installed at each appliance connection, minimum 75 mm long

5. Confirm gas piping passing through walls or floors is sleeved and the annular space is sealed with approved non-combustible material

- CSST not bonded to the grounding system, risking damage from lightning-induced currents

- Sediment traps (drip legs) missing at appliance connections

- Improper thread sealant used or joints not adequately tightened

- Gas piping not sleeved where passing through foundation walls

Per CSA B149.1, all new gas piping and additions to existing piping must be pressure tested before being placed in service. The test must be performed at 1.5 times the maximum working pressure or a minimum of 15 psi (103 kPa), whichever is greater, for a minimum of 10 minutes with no detectable pressure loss. Testing must use air, nitrogen, or carbon dioxide — never combustible gas. All test results must be documented and available for the inspector.

1. Verify the pressure test is conducted at the required pressure (minimum 15 psi / 103 kPa or 1.5 times working pressure) per CSA B149.1

2. Confirm the test duration is a minimum of 10 minutes with no detectable pressure drop on the gauge

3. Check that the test medium is air, nitrogen, or CO2 — confirm no combustible gas is used for testing

4. Verify all openings are capped or plugged during the test and the system is isolated from the gas metre

5. Review the pressure test documentation including date, pressure, duration, and the fitter's certification

- Test pressure below the minimum required by CSA B149.1

- Test duration too short to detect slow leaks

- Pressure test performed with gas in the line instead of an inert medium

- Test results not documented or not available for the authority having jurisdiction

Per CSA B149.1 and NBC Part 9, fuel-burning appliances must be vented to the outdoors through approved venting systems. Conventional venting (Type B vent) must maintain minimum clearances to combustibles and proper rise-per-run ratios. Direct-vent and sealed combustion appliances must have intake and exhaust terminations per manufacturer's specifications and CSA B149.1 clearance requirements from openable windows, doors, and air intakes. Power-vented appliances require listed vent materials.

1. Verify vent type matches the appliance category (Type B for conventional, approved plastic for high-efficiency condensing appliances)

2. Confirm vent sizing per CSA B149.1 vent sizing tables for the appliance BTU input and vent configuration

3. Check that vent terminations maintain minimum clearances from windows, doors, gas metres, and air intakes per CSA B149.1

4. Verify the vent has adequate slope (minimum 20 mm per metre upward for conventional vents) and is supported at required intervals

5. Confirm common vent systems (shared vents) are sized for the combined appliance input and worst-case operating conditions

- Vent termination too close to openable windows or air intakes

- Vent diameter undersized for the appliance BTU input causing spillage

- Improper vent material used for high-efficiency condensing appliances (e.g., Type B instead of approved plastic)

- Common vent not resized after one appliance is replaced with a direct-vent unit

Per CSA B149.1 and NBC Section 9.33, all fuel-burning appliances require an adequate supply of combustion air. For appliances in confined spaces, combustion air must be supplied through permanent openings to the outdoors or to adjacent spaces of adequate volume. The required opening sizes are based on the total BTU input of all appliances in the space per CSA B149.1 tables. Sealed combustion and direct-vent appliances draw combustion air from outdoors and are exempt from room volume requirements.

1. Calculate total BTU input of all fuel-burning appliances in the mechanical room or confined space

2. Verify combustion air opening sizes meet CSA B149.1 requirements for the total connected BTU load

3. Confirm combustion air ducts, where used, are the same cross-sectional area as the required opening and terminate in an unobstructed location

4. Check that combustion air openings are not blocked, screened with fine mesh, or otherwise restricted

5. Verify that sealed combustion appliances have dedicated outdoor air intakes properly connected and unobstructed

- Combustion air openings undersized for the total appliance load in the space

- Combustion air openings blocked by storage, insulation, or other obstructions

- Fine mesh screens on combustion air intakes that restrict airflow and accumulate lint or frost

- Mechanical room door sealed too tightly without an alternative combustion air path

Per CSA B149.1 and CAN/CSA-6.19, all gas piping joints and connections must be tested for leaks using an approved leak detection solution or combustible gas detector after the system is charged with gas. Carbon monoxide (CO) alarms must be installed per provincial building code requirements (typically outside each sleeping area and on every storey with a fuel-burning appliance). Combustion testing must confirm safe flue gas CO levels in appliance exhaust.

1. Test all accessible joints, valves, and connections with an approved leak detection solution or combustible gas detector per CSA B149.1

2. Verify CO alarms are installed outside each sleeping area and on every storey containing a fuel-burning appliance per CAN/CSA-6.19

3. Perform combustion analysis on each fuel-burning appliance to confirm CO levels in the flue gas are within acceptable limits

4. Check that the gas shut-off valve for each appliance is accessible, labelled, and operational

5. Verify the main gas shut-off valve location is identified and accessible for emergency use

- Gas leaks at connections not detected due to incomplete leak testing

- CO alarms not installed or installed in incorrect locations per provincial requirements

- Appliances producing elevated CO due to improper combustion air supply or heat exchanger failure

- Individual appliance shut-off valves inaccessible behind finishes or equipment

Per CSA B149.1 and manufacturer's installation instructions, all gas appliances must maintain minimum clearances to combustible materials as specified on the appliance nameplate and in CSA B149.1 Table 5.1. Appliances must be installed level, on approved bases or supports, and connected with approved connectors. Water heaters in garages must have the ignition source elevated a minimum of 450 mm above the floor per CSA B149.1.

1. Verify clearances from the appliance to combustible materials meet the values on the appliance nameplate and CSA B149.1 Table 5.1

2. Confirm gas appliances in garages have ignition sources elevated minimum 450 mm above the floor per CSA B149.1

3. Check that flexible gas connectors are CSA-approved, of the correct length, and not concealed within walls or floors

4. Verify the appliance is installed level on an approved base and the gas connection does not strain the piping

5. Confirm the appliance nameplate is visible and accessible for inspection after installation

- Combustible storage placed within the required clearance zone around appliances

- Gas water heaters in garages with ignition sources below the 450 mm elevation requirement

- Flexible connectors concealed in walls or used through floors, contrary to CSA B149.1

- Appliance nameplates obscured or removed preventing verification of clearance requirements