TSSA G3 safety, WHMIS and fire practice questions (Module 1).

Five free practice questions on safety, WHMIS and fire: module 1 of the nine modules of Ontario's Gas Technician 3 (G3) certificate exam, which TSSA runs. The exam is all multiple choice; these have four options and one correct answer, as every question in our bank does. Answer each one before opening the explanation. No account, no email.

01The questions

1. Procedural · Duties of workers: use the protective equipment required, report hazards and defects, work safely

   To thread a short pipe nipple, a G.3 finds that the guard on his employer's power threading machine is in the way. Under the Occupational Health and Safety Act, when may he take the guard off?

   1. When his supervisor gives a written waiver for that one job
   2. When he fits an adequate temporary guard and refits the original once done
   3. When the guard is the employer's own and not one that a regulation requires
   4. When he is the only worker using the machine on that job
   Show the answer

   B. Correct. OHSA s. 28(2)(a): no worker shall remove or make ineffective a protective device required by the regulations or by the employer without providing an adequate temporary protective device, and the device is replaced immediately once the need for removing it has ceased.

   Why not the others

   A. A supervisor's signature does not change the worker's own duty. Under s. 28(2)(a) the guard may come off only with an adequate temporary protective device in its place, and it goes back on as soon as the need ends.

   C. The rule covers both: a protective device required by the regulations or by the employer (s. 28(2)(a)). The employer's guard comes off only with an adequate temporary device in place, and is replaced immediately afterwards.

   D. Working alone does not exempt anyone. The s. 28(2)(a) duty applies to every worker: provide an adequate temporary protective device, and refit the guard as soon as the need for removing it has ceased.

2. Recall · Safety organizations and their roles: Ministry of Labour inspectors, joint health and safety committees and representatives, WSIB, sector safety associations, TSSA for fuels

   A gas contractor regularly employs eight workers, and no order or regulation requires it to have a joint health and safety committee. What does the Occupational Health and Safety Act require for worker representation?

   1. At least one health and safety representative, chosen by the company's owner
   2. A joint health and safety committee of at least two members
   3. No representative, since fewer than 20 workers are employed
   4. At least one health and safety representative, selected by the workers
   Show the answer

   D. Correct. OHSA s. 8(1): where no committee is required under s. 9 and the number of workers regularly exceeds five, the employer causes the workers to select at least one health and safety representative from among workers who do not exercise managerial functions.

   Why not the others

   A. The representative is selected by the workers who do not exercise managerial functions, or by their trade union (s. 8(1) and (5)), not chosen by the owner or the employer.

   B. A joint committee is required where 20 or more workers are regularly employed, or where an order or a designated-substance regulation applies (s. 9(2)). With eight workers and no order, the Act calls for a health and safety representative instead (s. 8(1)).

   C. Twenty is the committee threshold (s. 9(2)), not the threshold for any representation. Where more than five workers are regularly employed, the workers select at least one health and safety representative (s. 8(1)).

3. Procedural · Lifting and moving appliances, cylinders and materials safely

   Under the direct supervision of a G.2, a G.3 has helped disconnect an old 40 USG (151 L) tank water heater in a basement. It must go up the stairs to the truck. What should be done first?

   1. Drain it halfway, so it is light enough for one person to carry
   2. Leave the water in, so the tank sits steady on the hand truck
   3. Lay it on its side and slide it up the stair treads on a blanket
   4. Drain the tank fully, then strap it to an appliance hand truck
   Show the answer

   D. Correct. Water weighs about 1 kg per litre, so a full 151 L tank carries roughly 150 kg of water on top of its own weight. Draining it removes that load; strapping it to an appliance hand truck, clearing the path and having a helper follow CCOHS's advice to use mechanical aids and get help with heavy or awkward loads.

   Why not the others

   A. Half a tank is still about 75 kg of water that sloshes as the tank tilts. Drain it fully and use a hand truck with a helper rather than a one-person carry.

   B. The water makes the load far heavier, about 1 kg per litre or roughly 150 kg for this tank, and it shifts as the tank tips. Drain it first, then move it on a hand truck.

   C. Sliding a tank up the stairs is uncontrolled, leaves any water's weight to fight, and can damage the treads. Drain the tank and move it strapped to a hand truck.

4. Recall · Hazardous materials met in gas work: joint compounds, solvents and cements, leak-detection solutions, insulation and old vent or duct materials, soot

   A G.3's half-mask respirator still carries the organic-vapour cartridges from a solvent job. He is about to brush and vacuum heavy soot from a boiler's vent connector. What should the respirator have for this task?

   1. Particulate filters, since its cartridges stop vapours, not particles
   2. No change, since the organic-vapour cartridges also trap soot particles
   3. Fresh organic-vapour cartridges, since used ones let fine soot through
   4. A supplied-air hood in place of the half-mask, since soot displaces oxygen
   Show the answer

   A. Correct. CCOHS: filters trap particles such as dusts and fumes, while chemical cartridges adsorb gases and vapours; a chemical cartridge respirator can carry a dust pre-filter. Soot is a fine particulate, so the half-mask needs particulate filters (or a particulate pre-filter) before he brushes, with the soot vacuumed rather than blown about.

   Why not the others

   B. Organic-vapour cartridges work by adsorbing gases and vapours on a sorbent; they are not made to trap particles (CCOHS). For soot the half-mask needs particulate filters or a particulate pre-filter.

   C. Used cartridges are replaced because they saturate with vapour, but a fresh cartridge is still a vapour sorbent, not a particle filter (CCOHS). Soot calls for particulate filters or a pre-filter.

   D. Soot is a dust; brushing it does not take oxygen out of the room. Supplied air is for oxygen-deficient or other immediately dangerous atmospheres (CCOHS). A half-mask with particulate filters suits this particulate hazard.

5. Recall · The fire triangle and how each extinguishing method works

   A G.3 puts out a small fire in a furnace closet with a carbon dioxide extinguisher. Why should he ventilate the closet before going back in to work?

   1. The CO₂ turns into carbon monoxide when it meets the hot furnace parts
   2. The CO₂ leaves a fine powder on the furnace that must be cleared off first
   3. The CO₂ worked by displacing oxygen, and the closet is still short of it
   4. The CO₂ becomes flammable once it mixes with any gas left in the closet
   Show the answer

   C. Correct. A CO₂ extinguisher works mainly by smothering: it displaces the oxygen the fire needs. In a small closed space it also displaces the oxygen people need, so the closet is ventilated before anyone works in it.

   Why not the others

   A. Carbon dioxide is a product of complete combustion and does not turn into carbon monoxide on contact with a hot furnace. The hazard after discharge is oxygen displacement.

   B. A CO₂ extinguisher leaves no residue; a dry-chemical unit is the one that leaves powder. The reason to ventilate is the oxygen the CO₂ displaced.

   D. CO₂ does not burn; it is used because it is inert. The reason to ventilate is that it displaced oxygen in the closet.

02Answer key

03What module 1 covers

How a gas technician stays safe and keeps others safe: the rights and duties of workers, supervisors and employers under Ontario's Occupational Health and Safety Act and the safety organizations that apply to gas work, choosing personal protective equipment, lifting and moving appliances and cylinders, ladders, roofs, attics and crawl spaces, isolating gas and power before servicing, WHMIS labels and safety data sheets, the hazardous materials met on the job, and fire safety, including what to do about a fire fed by escaping gas.

TSSA names module 1 “Protect Self and Others”. It gives its G3 curriculum only to accredited training providers, so the four objectives below are TicketPrep's own, built from public sources such as college course outlines and Ontario's regulations, not TSSA's. TSSA does not publish the G3 question count or how many exam questions come from each module: its prep guide gives no G3 count and no per-module count, and candidates who fail get a mastery report broken down by module. The right-hand column is how many questions our bank holds on each objective, Standard and Advanced together, not a count from the exam.

04What the questions turn on

Duties run in every direction

A supervisor must tell a worker about any danger the supervisor knows of, such as a rotting platform under an attic furnace. A worker must report missing or defective equipment, like a gas detector that fails its start-up self-test, to the employer or supervisor. When a worker is critically injured, the employer tells an inspector right away and sends a written report within 48 hours.

Low spaces and the limits of a respirator

Propane vapour is heavier than air and collects in crawl spaces and other low spots, so the space is tested at floor level and entered only within the employer's limit. An air-purifying respirator adds no oxygen, so it is no protection in a space short of it. An oxygen meter alone cannot clear a space either: a small drop in oxygen can mean gas close to its lower explosive limit, so the space is ventilated and checked with a combustible-gas detector.

Labels, safety data sheets and 'empty' cylinders

A WHMIS label's precautionary statements tell users how to prevent or respond to harm, such as not putting out a leaking-gas fire unless the leak can be stopped. The employer must keep a current safety data sheet readily available for each hazardous product, and an electronic copy counts. An 'empty' propane cylinder still holds flammable vapour: its valve stays closed, it is marked empty and it is stored apart from full ones.

Stop the gas before fighting the fire

Closing a valve removes the fuel, which is why a gas-fed fire is stopped at a valve rather than smothered while gas keeps flowing. If the valve cannot be reached safely, everyone gets out, 911 is called from outside and the gas is shut off at the meter if that can be done safely. A cylinder in a fire whose relief valve is venting with a rising roar is a reason to withdraw, not to reach for its valve.

05The other modules

The G3 exam covers nine modules, 1 to 9. Each has its own page of free questions:

The TSSA G3 practice test page describes the full question bank. How these questions are written and checked: how our questions are made. Found a mistake? Tell us and we will fix it.