11.2 Pressure Testing, Leak Testing & the Ontario Test Tag (Clause 6.22)

Pressure testing is the quality gate between installing gas piping and putting gas into it. CSA B149.1 Clause 6.22 (Testing of piping, tubing, hose, and fittings) sets the rules, Ontario's Gaseous Fuels CAD adds a mandatory test tag, and O. Reg. 215/01 s. 22(1) lets a signed-off G.3 holder install and test piping under 2-1/2 in. and complete the pressure test tag.

1. When a Pressure Test Is Required (Clause 6.22.2)

Before an appliance is connected and before fuel gas is introduced, a new gas piping system—or a replacement, modification or addition to an in-service system—that contains fittings or joints not yet exposed to fuel gas must be pressure tested. Test before piping is concealed or buried, so every joint can still be reached. Clause 4.3.7 makes gas-tightness and pressure testing part of the installer's responsibilities.

Test media

Clause 6.22.2 permits only air, an inert gas (such as nitrogen), or carbon dioxide.

Isolate what cannot take the test pressure (Clause 6.22.2(a))

Appliance shut-off valves not rated for the test pressure, meters and pressure regulators must not be connected to the piping under test. A residential combination gas valve is typically rated for about 1/2 psig (14 in. w.c.); a 15 psig test would damage its diaphragms and seats. Cap or plug every outlet with fittings rated for the test pressure (never plastic shipping caps).

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2. Reading Table 6.3 (Test Pressure and Duration)

Table 6.3 gives the minimum test pressure and test duration based on the system's maximum operating pressure and the size and length of the piping. Its values are minimums; circumstances can call for a higher pressure or longer test. Examples:

• A typical residential natural gas system at 7 in. w.c., within 200 ft (60 m), is tested at 15 psig for 15 minutes.
• The SkilledTradesBC fuel-gas textbook works two examples from the code table: a 2 psig system 50 m long needs 15 psig for 15 minutes, while the same system 70 m long needs 15 psig for 60 minutes—length, not just pressure, drives the duration.
• Ontario CAD (Table 6.3 note 2): wrapped or factory-coated piping or tubing of any size and length—other than CSST and coated copper tubing—is tested at a minimum of 100 psig (700 kPa) for the duration the table gives.
• For propane, the Table 6.3 notes define maximum operating pressure as 250 psi for piping at container pressure, 350 psi at the outlet of a pump or compressor, and 375 psi (or the hydrostatic relief valve setting) for liquid lines that can be isolated.

Always open the code book to Table 6.3 for the row that matches your system rather than relying on memory.

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3. Test Gauges and Recorders (Clause 6.22.2(b)–(c))

For a 15 psig test, the gauge must read to at least $15 \times 1.15 = 17.25\text{ psig}$. Trade training (for example the SkilledTradesBC text) applies the upper limit as about 45 psig for a 15 psig test, so a 0–30 psig gauge is the usual choice; its divisions must be no larger than $2\% \times 30 = 0.6\text{ psig}$. A 0–150 or 0–300 psig gauge is far too coarse: a small leak would barely move the needle.

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4. Running the Test

1. Pressurize with air, nitrogen or CO2 to the Table 6.3 test pressure.
2. Isolate the source. Clause 6.22.1 requires the source of test pressure to be isolated while the system is under test, and the system must hold the test pressure for the full duration without any drop.
3. Allow for temperature. Gas pressure follows absolute temperature ($P_1/T_1 = P_2/T_2$). Air heated by compression cools to room temperature and the pressure falls slightly; piping in sunlight warms and the pressure rises. Good practice is to let the system stabilize for several minutes before recording the starting pressure and timing the test.
4. Any drop is a failure. Find the leak with a leak-detection solution under test pressure, then depressurize completely before repairing—never tighten a joint under pressure—and repeat the full test.

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5. After Appliances Are Connected (Clause 6.22.3 and 6.22.4)

When an appliance is first activated after installation, or gas is reintroduced after an interruption of service, the piping from the isolating valve through to the appliance valve train is leak tested with gas:

1. Make sure every opening from which gas could escape is closed.
2. Let gas into the piping and watch the meter test dial, or a pressure gauge or manometer, to confirm no gas is escaping.
3. Where there is no meter, use a gauge with increments no larger than 1 in. w.c. for systems up to 0.5 psig, or 2 in. w.c. for systems over 0.5 psig up to 5 psig.
4. Hold the test for 10 minutes.
5. Check each appliance connection, valve, valve train and component at normal operating pressure with a liquid solution or a leak-detection device. If leakage is found, shut off the gas to the appliance until it is repaired.

Clause 6.22.4 (new in 2025) adds a valve-train leak test of threaded and flanged connections at operating pressure, and the new informative Annex K describes allowable leakage for valve-train components. Trade practice also checks for a seeping meter valve: with the system holding gas and the meter valve closed, bleed a little pressure off—if the pressure creeps back up, the meter valve is passing gas and must be serviced before the test is valid.

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6. The Ontario Pressure Test Tag (CAD Clauses 6.22.7–6.22.8)

Immediately after the pressure test (6.22.2) or the leak test (6.22.4), the person who performed it must attach a tag to the piping, tubing system or appliance, in a readily accessible location protected from the environment, stating:

A sticker with the same information may be used instead of a tag, placed on a visible, readily accessible and non-removable surface of the appliance (6.22.8).