Gasfitter - Class A — Red Seal

Performs common occupational skills

Which item provides primary respiratory protection when soldering brass fuel fittings indoors?

1. Safety glasses with side shields
2. A half-face respirator with the correct cartridge
3. Hearing protection rated for shop noise
4. Cut-resistant gloves for hand defence

A half-face respirator with a cartridge rated for metal fumes and organic vapours is the controlling protection because soldering brass releases zinc-oxide fume and flux smoke that the lungs cannot otherwise filter. Safety glasses defend the eyes from spatter but pass air freely. Hearing protection covers a different hazard class entirely and does nothing for inhaled fume. Cut-resistant gloves address sharp burrs at the joint but do not change the air the worker breathes, so they cannot substitute for an air-purifying respirator when fume is present at the work zone.

RSOS 2024 | A-1.02 Uses personal protective equipment (PPE) and safety equipment

Installs fuel piping and tubing systems

What is the correct way to deburr black-iron pipe after cutting?

1. Tap the inside with a hammer until rough edges fall
2. Leave the burr in place because thread sealant will fill it
3. Use a reaming tool or file to remove the inside and outside burr
4. Heat the end with a torch until the burr melts away

A reaming tool or file removes the inside burr that would otherwise restrict flow and trap metal chips, and it removes the outside burr that would cut into thread sealant and prevent a clean engagement at the fitting. Hammer impact deforms the wall and can crack the pipe end, leaving the burr embedded. Sealant cannot bridge a torn metal lip and will eventually shred at that point, creating a leak path. Heating the end with a torch alters the steel temper, contaminates the bore and never removes a metal burr — it only oxidizes it onto the wall.

RSOS 2024 | B-5.02 Prepares piping for fuel systems

Installs venting and air supply systems

A high-efficiency furnace at 95% AFUE is being installed. Which vent category and material family fit the design?

1. Category I — single-wall galvanized vent connector
2. Category II — corrugated aluminum liner
3. Category III — sealed-joint single-wall vent
4. Category IV — condensing plastic/stainless steel

A 95% AFUE furnace operates as Category IV — positive pressure and condensing — so the vent must use a listed condensing-vent material (plastic or stainless steel) with sealed joints that handle both the pressure and the acidic condensate. Category I single-wall galvanized vent is rated for natural draft and corrodes rapidly in condensate. Category II liners suit negative-pressure condensing installations and cannot contain positive pressure. Category III sealed single-wall vent handles positive pressure but is not corrosion-resistant against condensate, so it fails when the flue cools enough to condense in the run.

RSOS 2024 | C-7.01 Selects materials for venting systems