Five free practice questions on safety, rigging and weld inspection: block A of the Red Seal 456A Welder exam, about 20 of its 125 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
-
An acetylene cylinder has arrived at a mine shop lying on its side. Why must it be stood upright and left for the period the supplier specifies before use?
- To let heat from transport escape so pressure falls
- To let the fusible plugs seat themselves again
- To let the acetone settle so it is not drawn out with the gas
- To let the porous filler dry out before withdrawal
Show the answer
C. Correct. Acetylene is dissolved in acetone held in a porous filler. When the cylinder lies down, acetone moves toward the valve and can be drawn into the regulator and hoses, damaging them and giving an unstable flame. Stand it upright, secure it, and wait the supplier's time.
Why not the others
A. Temperature does affect pressure, but that is not why the rule exists. The concern is liquid acetone near the valve.
B. Fusible plugs are safety devices that melt in a fire; their position does not change when the cylinder is laid down.
D. The porous filler is meant to hold acetone, not to be dry. Standing the cylinder up lets the acetone settle away from the valve.
-
An inverter power source in a module yard has a heavy build-up of grinding dust inside. How do you clean it?
- Wash the boards with a water-based degreaser
- Isolate it, wait for capacitors, use dry low-pressure air
- Unplug it and blow it out with the shop's wet air line
- Blow it out at full shop pressure while it runs
Show the answer
B. Correct. Lock out and unplug the machine, wait the maker's time for the capacitors to discharge, then remove the covers and blow the dust out with dry, low-pressure air or vacuum it. How often depends on how dusty the site is.
Why not the others
A. Liquids on electronic boards can cause tracking and corrosion. Makers call for dry compressed air (or a vacuum), not wet cleaning.
C. Unplugging is the right start, but inverters store charge in capacitors after unplugging, and wet air puts water into the electronics. Wait for discharge and use a dry air supply.
D. A running machine is live inside and the fan redistributes the dust. It is isolated first, and high-pressure air can drive debris into boards and damage components.
-
The SDS for a stainless-steel pickling paste used on a food-plant job lists hydrofluoric acid as an ingredient. Besides an eyewash, which first-aid supply does such an SDS typically require on hand?
- Burn gel for thermal burns
- Calcium gluconate gel
- A vinegar rinse
- Baking soda paste
Show the answer
B. Correct. Hydrofluoric acid penetrates skin and draws calcium from tissue; calcium gluconate gel, applied after flushing with water, binds the fluoride. Seek medical attention for any HF exposure, even if it does not hurt at first.
Why not the others
A. Thermal burn gel cools heat burns; it does not stop fluoride ions penetrating the tissue. HF exposure needs calcium gluconate gel after flushing with water.
C. Vinegar is an acid and does nothing to neutralize an acid burn. Flush with water, then apply calcium gluconate gel as the SDS directs.
D. Baking soda is a general acid neutralizer, but hydrofluoric acid burns need a specific treatment that binds fluoride ions. The SDS names calcium gluconate gel.
-
Before rigging it, you calculate the weight of a mild-steel plate 2400 mm × 1200 mm × 25 mm. Steel density is 7.85 g/cm³. What is its mass?
- 72.0 kg
- 565.2 kg
- 5652 kg
- 56.5 kg
Show the answer
B. Correct. Volume = 240 cm × 120 cm × 2.5 cm = 72 000 cm³. Mass = 72 000 × 7.85 = 565 200 g = 565.2 kg. Add the rigging to get the total hook load.
Why not the others
A. 72.0 kg treats the 72 000 cm³ (72 L) volume as if it were water at 1 g/cm³. The volume must be multiplied by steel's density, 7.85 g/cm³.
C. 5652 kg comes from dividing the mm³ volume by 100 instead of 1000. The plate is 72 000 000 mm³ = 72 000 cm³.
D. 56.5 kg comes from converting the 25 mm thickness to 0.25 cm instead of 2.5 cm, giving 7200 cm³. 25 mm = 2.5 cm, so the volume is 72 000 cm³.
-
You are scheduled to weld handrail brackets on a food-plant mezzanine at 10:00. The hot-work permit was signed at 07:00 and a fire watch is arranged. At 09:45 painters set up 8 m below and begin spraying a solvent-based coating. What do you do?
- Start on time; the permit is already signed
- Ask the painters to stop spraying only while you strike each arc
- Start, with the fire watch holding an extinguisher on the painters
- Hold the hot work and coordinate with the painters and permit issuer
Show the answer
D. Correct. Conditions have changed, so the permit no longer matches the site. Hold the work, tell your supervisor and the permit issuer, and agree a sequence with the painters' lead (paint later, or weld once vapour has cleared and the area is re-checked) before resuming.
Why not the others
A. The permit was written for the conditions at 07:00. A spray operation with flammable solvent vapour nearby is a new hazard the permit did not cover.
B. Solvent vapour stays in the air long after spraying stops, and sparks are thrown throughout welding, not just at arc strike. Intermittent pauses do not control the hazard.
C. An extinguisher responds to a fire; it does not stop solvent vapour being ignited by sparks. The hazard has to be removed before hot work starts.
02Answer key
| Question | Answer | Sub-task |
|---|---|---|
| Q1 | C | Stores welding consumables and gas cylinders |
| Q2 | B | Maintains welding equipment |
| Q3 | B | Maintains safe work environment |
| Q4 | B | Uses material handling equipment |
| Q5 | D | Plans job tasks |
03What block A covers
This block covers the common skills behind every welding job. It includes maintaining hand tools, grinders and oxy-fuel and plasma equipment, ladders, scaffolds and aerial work platforms, rigging and sling angles, hazard assessment, hot work and confined-space gases, PPE and respirators, welding symbols and drawings, WPS and WPDS documents, visual inspection and NDT, preheat checks, electrode storage, and choosing a process and power source.
The Red Seal Occupational Standard names this block “Performs common occupational skills”. It carries 16% of the exam, about 20 of the 125 questions, split across six 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 |
|---|---|
| Maintains tools and equipment Maintains hand, power, layout and measuring tools; Maintains stationary machinery; Maintains thermal cutting equipment; Maintains welding equipment | 25% |
| Uses access and material handling equipment Uses access equipment; Uses material handling equipment | 15% |
| Performs safety-related activities Performs hazard assessments; Maintains safe work environment; Uses personal protective equipment (PPE) and safety equipment | 25% |
| Organizes work Uses documentation and reference material; Interprets drawings and welding symbols; Plans job tasks; Organizes materials | 15% |
| Performs routine trade activities Performs quality inspection; Marks welds, materials and parts; Controls temperature of weldments; Stores welding consumables and gas cylinders; Selects welding processes and power source; Performs equipment start-up and shut-down; Finishes final product | 28% |
| Uses communication and mentoring techniques Uses communication techniques; Uses mentoring techniques | 2% |
04What the questions turn on
Sling angles and hitches
Leg tension is the load divided by the number of legs, times the angle factor: 1.414 at 45° and 2.000 at 30°. A choker hitch is typically rated at about 75 % of the sling's vertical capacity.
Reading the welding symbol
A weld symbol below the reference line means the arrow side, and above it means the other side. In an intermittent callout such as 50-150, 50 is the segment length and 150 the pitch, so the clear gap is 100.
Proving preheat and interpass
Use two crayons: one rated at the minimum preheat should melt, and one rated at the maximum interpass should not. Mark the base metal at the distance the WPDS gives. On bright aluminum, an infrared thermometer reads far low.
Argon pools low
Argon is about 1.4 times as dense as air, so leaking purge gas collects low around the welder while a monitor at the manway reads normal air. Dizziness and clumsiness are early signs of oxygen deficiency, so monitor at the work.
05The other blocks
The 456A exam has four blocks. Each has its own page of free questions:
The 456A Welder 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.