420B Red Seal — Ironworker

About the 420B Red Seal Exam — Ironworker

The 420B Ironworker Red Seal exam is Canada's national certification for ironworkers who erect structural steel, place reinforcing rod, and perform rigging and hoisting on construction sites. A Red Seal 420B endorsement proves your skills meet the national standard and is recognized in every province without re-examination.

The exam has approximately 120 multiple-choice questions based on the 2023 RSOS, with a 70% passing score. Exam time is 3 hours.

Topic Breakdown (2023 RSOS)

• Structural Steel Erection (~20%) — Column setting, beam connections, high-strength bolt installation (turn-of-nut, DTI), plumbing and levelling, temporary bracing, AISC/CISC code. The heaviest block.
• Rigging & Hoisting (~18%) — Wire rope inspection, sling angle derating, WLL calculations, shackles, hooks, taglines, crane hand signals, load chart reading. Expect math questions.
• Welding & Cutting (~15%) — SMAW/FCAW for structural steel, preheat on A36/A572, CSA W47.1 certification, weld symbols, fillet weld sizing, OFC and plasma cutting.
• Blueprint Reading & Layout (~13%) — Structural drawing symbols, column grids, elevation marks, piece marks, connection details, section views, anchor bolt layout.
• Reinforcing Steel (~13%) — Rebar designation/grades (400/500), development length, lap splices, hooks, cover requirements, tying, placement tolerances (CSA A23.1).
• Safety & Fall Protection (~12%) — 100% tie-off, PFAS components, controlled decking zones, safety netting, leading edge work, anchor strength, fall clearance math.
• Tools & Equipment (~9%) — Spud wrenches, drift pins, ironworker machines, come-alongs, beam clamps, burning bars, tensioning tools.

Exam Strategy for 420B

Rigging math is guaranteed. Practice sling angle calculations and two-leg bridle sling WLL problems — these are straightforward marks once you know the formula.

Fall protection rules = free marks. Memorize controlled decking zone rules, 100% tie-off requirements, and PFAS components. These questions are specific and testable.

Blueprint reading is on every exam. Practice reading structural drawing symbols, piece marks, and weld symbols from a connection detail.

How to Use This Tool

100 questions across all 7 blocks with full explanations. Use Topic Filter to drill weak areas; use Mock Exam Mode 2–3 weeks before exam day.

Related reading: How to Pass the 420B Exam | Ironworker Salary Guide | Ironworker Career Guide