Gasfitter - Class B — Red Seal

Performs common occupational skills

A gasfitter is decanting a small quantity of thread-sealing solvent from its original supplier-labelled container into an unlabelled spray bottle for use on a residential service call. What is the correct labelling practice for the spray bottle before it leaves the truck?

1. Leave the spray bottle unlabelled, since the original supplier container stays on the truck and can be checked whenever a hazard question comes up
2. Apply a workplace label that identifies the product, gives safe-handling information, and references the safety data sheet for that product
3. Mark the bottle only with the decanting date, since a dated container is treated as fully identified for the shift it is used on that call
4. Copy just the product's trade name onto masking tape, since the safety data sheet stored in the truck's binder covers the labelling requirement

The correct answer holds because a workplace label must travel with the decanted product, naming it, summarizing safe-handling precautions, and pointing to the safety data sheet so anyone handling the bottle has hazard information at hand. Leaving the bottle unlabelled and relying on the original container back in the truck fails because hazard information must be on the container actually in use, not stored elsewhere. Dating the bottle alone shows when it was filled but says nothing about its contents or safe handling. Writing only the trade name on tape and trusting the truck's safety data sheet to cover the gap still leaves the next worker without the hazard and precaution details a workplace label must carry.

RSOS 2024 | A-1.01 Maintains safe work environment

Installs fuel piping and tubing systems

A new residential gas piping system operating at 7 in WC has been installed and capped. What is the required pre-service leak-and-strength test pressure and observation criterion before placing the system in service?

1. Test at the normal working pressure of 7 in WC for five minutes, watching the manometer for a pressure increase rather than any drop as proof of tightness
2. At least 1½ times working pressure but in no case less than 14 in WC above operating pressure, with no observable drop over the test period
3. Pressurize with compressed air to 5 psi and hold for two minutes, judging tightness only by listening for an audible hiss at each joint instead of a gauge
4. Charge the piping with fuel gas at line pressure and check every joint and fitting for leaks by passing an open candle flame slowly along each seam

The correct pre-service test uses at least one-and-a-half times the working pressure, never less than a 14-inch column above operating, held long enough on the manometer to confirm no observable drop, commonly about ten minutes for residential systems. Testing only at the normal 7-inch working pressure gives no safety margin, and watching for a rise instead of a drop misreads how a leak actually shows itself. Substituting 5 psi of compressed air with only an audible-hiss check skips the required gauge reading and pressure margin. Introducing fuel gas and probing joints with an open flame turns the test itself into an ignition hazard and is never permitted.

RSOS 2024 | B-5.03 Installs piping for fuel systems

Installs venting and air supply systems

A sidewall vent termination for a residential furnace is being located beside a gas-service regulator vent outlet. What minimum horizontal clearance from the regulator vent outlet must the vent termination maintain?

1. Clearance applies only to
2. 300 mm (12 in) in the
3. 1 m (3 ft)
4. No clearance is required

Sidewall vent terminations must be located at least 1 m (3 ft) measured horizontally from the vent outlet of any gas-service regulator, to prevent flue gas from being drawn back into the building through the regulator vent when the appliance fires. A 300 mm clearance is well below the published value and is a common failure pattern on tight residential sidewalls. Treating the clearance as optional ignores a documented spillage path that has caused indoor carbon-monoxide incidents. The clearance applies to residential installations equally with commercial ones — there is no residential exemption from regulator-vent clearances, and inspectors check this exact dimension routinely on new sidewall terminations.

RSOS 2024 | C-7.03 Installs venting systems