Five free practice questions on safety, tools, welding and drawings: block A of the Red Seal 308A Sheet Metal Worker exam, about 24 of its 120 questions. They are in the exam's format: four options, one correct answer. Answer each one before opening the explanation. No account, no email.
01The questions
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An inspector marks undercut on the SMAW fillet welds of a steel equipment rail for a rooftop fan. What is undercut?
- Weld metal rolled onto the base metal at the toe without fusion.
- Gas pockets trapped inside or on the face of the weld.
- A groove melted into the base metal at the toe and not filled.
- A fillet with one leg shorter than the other.
Show the answer
C. Correct. Undercut is a groove melted into the base metal along the toe of the weld and left unfilled by weld metal, usually from too much current, too long an arc or a poor electrode angle. It reduces the section and can start cracks under load.
Why not the others
A. Weld metal lying on the surface at the toe without fusing is overlap (cold lap). Undercut is the opposite: metal missing from the base metal at the toe.
B. Trapped gas pockets are porosity. Undercut is a groove along the toe of the weld.
D. Unequal legs are a size or profile fault. Undercut is base metal melted away at the toe and not filled.
Source: Red Seal Occupational Standard, sub-task A-2.06
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In a renovation, a new 30 in. × 12 in. duct will pass through an existing concrete block wall. Before laying out the opening, which drawings of the existing building show conduit and boxes that may be in or on that wall?
- The structural drawings.
- The electrical drawings.
- The architectural drawings.
- The mechanical drawings.
Show the answer
B. Correct. Conduit runs, boxes and panels are shown on the electrical drawings. Checking them before cutting, and confirming on site because old drawings may not show later changes, avoids cutting into a live circuit and lets the electrician reroute anything in the way.
Why not the others
A. Structural drawings show the wall's role in the structure, lintels, bond beams and reinforcement, which also matter for the opening. They do not show electrical conduit and boxes; the electrical drawings do.
C. Architectural drawings show wall types, fire ratings, doors and finishes. Conduit in or on the wall is the electrical designer's work and appears on the electrical drawings.
D. The mechanical drawings show the new duct and its route through the wall, not the electrical services already there. Those are on the electrical drawings.
Source: Red Seal Occupational Standard, sub-task A-3.02
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Flashing is being installed around a new exhaust fan curb on a flat roof, 2 m (6 ft) from an existing plastic dome skylight. How is the skylight treated during the work?
- As an opening, covered or guarded before work starts.
- As roof surface, since the dome is built for snow load.
- As a trip hazard, marked with flags or paint.
- As safe, once every worker is told where it is.
Show the answer
A. Correct. A skylight dome is built to shed weather and carry snow, not to stop a worker who trips or steps back onto it, and workers have fallen through them. It is treated as a roof opening: screened, covered or guarded as the site's fall-protection rules require.
Why not the others
B. Snow is a spread, steady load; a person falling or stepping onto the dome puts a sudden concentrated load on it that domes are not designed to carry. It is treated as an opening.
C. Marking makes the skylight easier to see, but it does nothing to stop a fall through it. A skylight near the work is covered, screened or guarded like any other roof opening.
D. Awareness helps, but workers handling sheet and watching their work still back into skylights. A physical cover, screen or guardrail is what prevents the fall.
Source: Red Seal Occupational Standard, sub-task A-1.02; CCOHS
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At the end of day shift you leave a half-finished duct riser in a shaft, and the night crew will carry on. What does your written handover note most need to state?
- The other trades in the shaft and their work hours.
- The hours worked and the material used on the riser.
- The tools left at the riser and where they are kept.
- Work finished and left plus any open hazards.
Show the answer
D. Correct. The night crew needs to know where the work stands and what could hurt them: an unguarded opening in the shaft, an unsupported section, a hanger not yet loaded. Writing it down means nothing depends on a hurried conversation at the shift change.
Why not the others
A. Knowing who else works in the shaft can help, but the night crew's first need is where the riser stands and what could hurt them: what is finished, what remains and any hazard left open.
B. Hours and material go on the time cards and job records. They do not tell the next crew where the riser stands or which hazards are still open; the note's job is the status of the work and its hazards.
C. Tools left behind are worth listing, but they are secondary. The incoming crew first needs what is finished, what remains and any hazard left open, such as an unguarded opening in the shaft.
Source: Red Seal Occupational Standard, sub-task A-4.01
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A new branch opening will be cut with a hand plasma torch into an existing 16 ga (0.0598 in.) black steel exhaust duct at a manufacturing plant. Before the arc is struck, what is checked about the duct?
- Whether it is level enough for a square cut.
- Whether the fan is running to clear the fume.
- Whether its hangers will carry the piece cut out of it.
- What lines its inside and whether deposits can burn.
Show the answer
D. Correct. Existing exhaust duct can be lined with insulation or coated inside with dust, grease or process residue, and sparks and molten metal fall inside it as the torch cuts. Finding out what is in there, and cleaning or protecting it, is part of preparing the material under the hot-work procedure.
Why not the others
A. Level has nothing to do with whether the cut will start a fire inside the duct. The first check is what lines or coats its inside.
B. A running exhaust fan draws sparks along the duct into whatever has built up inside it, and the fan should be locked out for the work anyway. The inside of the duct is checked first.
C. The piece removed for a branch is small and comes out by hand. The hazard to check first is combustible material inside the duct that sparks will reach.
Source: Red Seal Occupational Standard, sub-task A-2.07
02Answer key
| Question | Answer | Sub-task |
|---|---|---|
| Q1 | C | Uses shielded metal arc welding (SMAW) equipment |
| Q2 | B | Interprets drawings |
| Q3 | A | Maintains safe work environment |
| Q4 | D | Uses communication techniques |
| Q5 | D | Uses oxy-fuel and plasma arc cutting equipment |
03What block A covers
The skills every sheet metal job rests on: PPE, fall protection and lockout, hand and power tools, shears and press brakes, GMAW, GTAW, SMAW and resistance spot welding, plasma and oxy-fuel cutting, soldering, measuring and testing instruments, lifts, hoisting and rigging, reading drawings and specifications, planning materials, basic duct design changes, and communicating with and mentoring others on the job.
The Red Seal Occupational Standard names this block “Performs common occupational skills”. It carries 20% of the exam, about 24 of the 120 questions, split across four tasks. The share column is each task's weight within the block, as the standard publishes it.
| Task and its sub-tasks | Share of block |
|---|---|
| Performs safety-related functions Uses personal protective equipment (PPE) and safety equipment; Maintains safe work environment; Performs lock-out and tag-out procedures | 22% |
| Uses and maintains tools and equipment Uses hand and portable power tools; Uses shop tools and equipment; Uses gas metal arc welding (GMAW) equipment; Uses resistance spot welding equipment; Uses gas tungsten arc welding (GTAW) equipment; Uses shielded metal arc welding (SMAW) equipment; Uses oxy-fuel and plasma arc cutting equipment; Uses soldering and brazing equipment; Uses measuring and layout equipment; Uses testing and inspection devices; Uses stationary and mobile work platforms; Uses hoisting, rigging and positioning equipment | 39% |
| Organizes work Uses trade-related documentation; Interprets drawings; Organizes materials and equipment for project; Performs basic design and field modifications | 26% |
| Uses communication and mentoring techniques Uses communication techniques; Uses mentoring techniques | 13% |
04What the questions turn on
Every energy source gets isolated
A locked disconnect controls only the motor's electrical energy. Air from other units turning a fan wheel, air trapped in a shear's hold-downs and steam feeding a humidifier are separate sources, each locked, bled or blocked before hands go in.
Match the heat to thin sheet
Thin sheet burns through easily. Use a smaller GMAW wire at lower current, hold an SMAW arc mainly on the heavier member and wash the puddle onto the thin edge, and plasma cut thin gauge with a fine-cut nozzle and faster travel.
Dividers step off chords, not arcs
A divider setting spans a chord, so stepping 16 divisions of a 220 mm circle along a line comes out 4.4 mm short. A stretch-out is calculated, or read off a circumference rule, which shows pi times the diameter directly.
Read sizes and elevations exactly
A duct marked 24 x 12 on a plan is 24 in. wide, the side seen in that view, unless the legend says otherwise. BOD is the bottom of the sheet metal, so insulation and the trapeze angle hang below it when rods are cut.
05The other blocks
The 308A exam has five blocks. Each has its own page of free questions:
The 308A Sheet Metal Worker practice exam 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.