Free Gasfitter - Class B Red Seal Examination Practice Questions

Sample Practice Questions

Try these 10 sample questions from the Gasfitter - Class B Red Seal Examination practice bank. Each includes the answer and explanation. Continue with the interactive practice above to review the full question set.

1. 1A gasfitter is inspecting a welding helmet before brazing work. Which component keeps fragments of a broken filter lens from reaching the eyes?

   1. A.Outer cover plate
   2. B.Clear retainer lensCorrect answer: B
   3. C.Heat-insulating gasket
   4. D.Opaque helmet shell

   Explanation: The source states: "A clear retainer lens made of plastic prevents any broken pieces of the filter lens from reaching the eye." The retainer lens provides this specific fragment barrier. The cover plate, gasket and shell perform different protective functions.

   Reference: CCOHS – Welding: Personal Protective Equipment and Clothing — What are the various components of welding hand shields and helmets?

2. 2A tubing cutter has left an inward burr on a copper gas tube. Which tool should the gasfitter use to restore the opening before making the joint?

   1. A.Tube bender
   2. B.Flaring cone
   3. C.Tube reamerCorrect answer: C
   4. D.Threading die

   Explanation: The source states: "ream tube and tubing to remove burrs from ends" The reamer removes the internal cutting burr. Benders change direction, flaring cones form a flare, and dies cut external threads.

   Reference: National Occupational Analysis – Gasfitter - Class B — B-4.01.08, printed page 21

3. 3A gasfitter is selecting a vent for an appliance that operates with positive vent static pressure and produces condensate in the vent. Which appliance category describes these conditions?

   1. A.Category I
   2. B.Category II
   3. C.Category III
   4. D.Category IVCorrect answer: D

   Explanation: The source states: "Category IV appliances operate with positive vent static pressure and a vent gas temperature that may cause condensate production in the vent." Category IV combines positive pressure with condensing conditions. Category I is nonpositive/noncondensing, II nonpositive/condensing, and III positive/noncondensing.

   Reference: ASHRAE Handbook – Chimney, Vent, and Fireplace Systems — Section 1 — appliance categories

4. 4A modulating burner must provide a maximum output of 120 kW and remain controllable down to 30 kW. What turndown ratio must its controller and burner arrangement support?

   1. A.2:1
   2. B.3:1
   3. C.4:1Correct answer: C
   4. D.5:1

   Explanation: The source states: "A gas burners turndown ratio is the ratio of maximum heat output to the minimum level of heat output at which the appliance will operate efficiently or controllably." Turndown = maximum ÷ minimum = 120 ÷ 30 = 4:1. 2:1 halves the maximum before dividing; 3:1 divides the output change (120 − 30) by the minimum; 5:1 divides the sum (120 + 30) by the minimum.

   Reference: SkilledTradesBC – Block B: Fuel Gas Systems — Modulating input

5. 5A gas-fired unit heater weighs 1.8 kN. Its specified suspension arrangement shares the static vertical load equally among three vertical rods. Before applying any required design factor, what load does each rod carry?

   1. A.0.3 kN
   2. B.0.6 kNCorrect answer: B
   3. C.0.9 kN
   4. D.5.4 kN

   Explanation: The source states: "the net external force on the system must be zero." Three equal upward rod forces balance 1.8 kN, so each carries 1.8/3 = 0.6 kN. Counting the two ends of each rod as six independent parallel supports incorrectly gives 1.8/6 = 0.3 kN. Omitting one of the three supporting rods gives 1.8/2 = 0.9 kN. Multiplying the total load by the rod count gives 1.8×3 = 5.4 kN instead of sharing it. The static result does not replace required design factors or anchorage assessment.

   Reference: OpenStax – College Physics 2e — 9.1 The First Condition for Equilibrium

6. 6A gasfitter is preparing a 30 psig piping pressure test. Which connected component must be isolated specifically because its pressure rating is below this test pressure?

   1. A.A shutoff valve rated for 150 psig
   2. B.A pipe fitting rated for 100 psig
   3. C.A line regulator rated for 10 psigCorrect answer: C
   4. D.A test hose rated for 50 psig

   Explanation: The source states: "Before testing, isolate or remove any components of the system that have a pressure rating below the test pressure to prevent any damage to these components." Only the 10 psig regulator would be exposed above its rating. The other listed ratings exceed 30 psig; this comparison does not replace the remaining test requirements.

   Reference: SkilledTradesBC – Gas piping and tubing pressure testing — Test Procedures — Prior to connecting the appliances

7. 7During inspection of a forced-air gas furnace, the gasfitter checks a metal barrier for cracks that could allow combustion products into the household supply-air stream. Which component provides this separation?

   1. A.Draft hood
   2. B.Gas pressure regulator
   3. C.Burner mixing tube
   4. D.Furnace heat exchangerCorrect answer: D

   Explanation: The source states: "In a properly operating forced-air furnace, the combustion air and the circulating air both flow through the furnace as it operates, but never mix" The heat exchanger transfers heat while separating the combustion-products passage from the circulating household air. The draft hood, gas regulator and burner mixing tube have other gas/venting functions and do not form that barrier.

   Reference: Natural Resources Canada – Combustion Gases in Your Home — Understanding Venting and Spillage — When Things Go Right, Circulation air

8. 8While using a hazardous pipe-cleaning product, a gasfitter needs the supplier's immediate instructions for an eye exposure. Which numbered SDS section contains the first-aid measures?

   1. A.Section 3
   2. B.Section 4Correct answer: B
   3. C.Section 6
   4. D.Section 8

   Explanation: The source states: "First-aid measures by route of exposure:" Section 4 lists first-aid measures, including eye contact. Section 3 concerns ingredients, section 6 accidental release, and section 8 exposure controls and personal protection.

   Reference: CCOHS – WHMIS: Safety Data Sheet (SDS) — What information is on the SDS? — section 4

9. 9The approved connection requires a flare on Type L copper tube. Which tube temper can be flared without first annealing a hard tube end?

   1. A.Annealed temperCorrect answer: A
   2. B.Quarter-hard temper
   3. C.Half-hard temper
   4. D.Hard-drawn temper

   Explanation: The source states: "soft temper tube should be used." Annealed is the soft condition specified for flaring. The harder tempers require different preparation; this question does not authorize an otherwise unapproved joint.

   Reference: Copper Development Association – Copper Tube Handbook — 9 Flared Joints, printed page 45

10. 10A natural-draft chimney is very tall relative to the heat supplied by its appliance. Which effect explains why adding height can fail to improve its actual draft?

    1. A.Cooling along the chimney can reduce the gas's buoyancy.Correct answer: A
    2. B.Lower friction loss along the chimney reduces available draft.
    3. C.Higher mean flue-gas temperature reduces the gas's buoyancy.
    4. D.Greater effective chimney height reduces theoretical draft.

    Explanation: The source states: "if a stack is overly tall in relation to the heat being sent out of the stack, the flue gases may cool before reaching the top. This condition may result in poor draft." Cooling reduces the hot-gas/cool-outdoor-air buoyancy difference. The other choices reverse the effects of friction, gas temperature or effective height: less friction preserves available draft, hotter flue gas increases buoyancy, and height increases theoretical draft when the other conditions are unchanged.

    Reference: SkilledTradesBC / TRU Open Press – Gas Appliance Draft — A-3.3 Gas Appliance Draft — Natural Draft