All 120 420B Practice Questions & Answers

A base plate distributes the concentrated column load over a larger bearing area on the concrete foundation, reducing bearing stress to within allowable limits.

The tapered end of a spud wrench is inserted into misaligned bolt holes in connections to align them so bolts can be inserted, temporarily holding members in place. The wrench end is used to snug bolts temporarily.

Turn-of-nut requires all bolts in the connection to be brought to the snug-tight condition first (full effort of an ironworker with a spud wrench), then a specified rotation is applied to achieve the minimum pretension.

Per AISC and CISC requirements, a minimum of two bolts or 25% of the bolt group (whichever is greater) must be installed and snug-tight before erection bolts are removed.

Plumbing up involves checking and adjusting the structure so columns are perfectly plumb (vertical) and beams are level before making final bolted or welded connections.

DTIs work by compressing their raised protrusions as bolt pretension increases. When sufficient tension is reached, the gaps between the protrusions and the contact surface fall below the specified maximum refusal value, verified with a feeler gauge.

AISC Code of Standard Practice allows ±6 mm (±1/4 inch) tolerance for anchor bolt location in plan. Significant deviations require engineered repair or replacement.

During erection, the structure is not yet a complete load-resisting system. Temporary bracing stabilizes the partially erected structure against gravity, wind, and erection equipment loads before permanent connections are complete.

A drift pin is a tapered steel pin driven through misaligned holes to align them so bolts can be inserted. It is similar in function to the tapered end of a spud wrench.

Decking must be placed from the crane or access side outward, never placing unsupported deck ahead of the safe access limit. OSHA/OHS regulations prohibit placing loose decking more than two beam spans ahead of secured decking.

W250x89 is a W-shape (wide flange) with approximately 250 mm nominal depth and a mass of 89 kg per metre of length. This is the CSA/metric designation for structural steel sections.

Shear studs are welded to the beam top flange and embed in the concrete deck above. They transfer horizontal shear forces between the steel beam and slab, creating composite behaviour that significantly increases beam capacity.

Per AISC erection safety requirements, at least two bolts or equivalent connections must be in place before releasing the crane hook from the member.

Column splices join upper and lower column sections in tall buildings where a single column piece would be impractical to handle. They are typically located about 600 mm above a floor level for access.

A490 bolts have higher yield and tensile strength than A325, resulting in higher minimum pretension requirements. Neither bolt type should be reused once fully tensioned (especially A490).

Structural steel, especially older or high-strength grades, becomes increasingly brittle and susceptible to impact fracture at low temperatures. Impact loads from erection (drops, hammer blows) can initiate brittle fracture.

Levelling nuts under the base plate allow the ironworker to adjust the plate precisely to exact elevation (plumb and level) before the column is grouted into final position.

TC bolts have a breakneck groove at the splined end. When minimum pretension is achieved, the torque reaction causes the spline to shear off cleanly, providing visual verification that the required minimum pretension has been reached.

ASTM A36 (equivalent to CSA G40.21 Grade 300W) has a minimum yield strength of 250 MPa (36 ksi) and minimum tensile strength of 400–550 MPa (58–80 ksi).

Camber is a deliberate upward curve fabricated into a beam so that under design load, the beam deflects back to a level position. Common in long-span or heavily loaded beams.

CISC and AISC erection guidelines require a minimum of 2 bolts per connection — or enough to safely support erection loads, as specified in the erection procedure or by the engineer — before the crane can release a member. One bolt provides insufficient rotation restraint — the connection can pivot. With 2 bolts at each end, the member is stable against rotation. Full bolt tightening follows per the erection sequence after multiple members create a stable structure.

Anchor bolt misalignment is a structural deficiency that requires engineering assessment before proceeding — notify the engineer and general contractor. Forcing the base plate distorts the anchor bolt, potentially cracking the grout and concrete embedment. Flame cutting a structural anchor bolt changes its material properties and may be prohibited. The engineer must determine if the misalignment is within tolerance, whether repositioning is possible, or if redesign is needed.

CISC erection tolerances for column plumbness: typically ±1:500 (1mm per 500mm height). At 6m height, allowable deviation is 6000/500 = 12mm. The measured 25mm deviation exceeds this. Out-of-plumb columns must be corrected before adding more load (next tier) because each additional tier multiplies the eccentricity and increases the risk of progressive collapse. Use come-alongs or guy wires to plumb the column.

Unexpected structural movement during a concrete pour is a serious warning sign of potential collapse — the structure may be overloaded or shores may be inadequate. Possible causes: shores inadequate for design load, concrete piling up (not spreading), formwork props kicked out, or deck load exceeding design. The safe action is to immediately stop the pour, ensure workers are clear of the affected area, and contact the engineer of record before proceeding. Progressive collapse can occur rapidly.

CSA S16 shear stud inspection: a failed bend test requires replacement of the failed stud and an increased testing rate. If a stud cracks at the weld during a 30° bend test, the weld quality is suspect. Replace the failed stud with a new one welded with correct parameters, and test additional studs at twice the original rate to verify that adjacent studs are acceptable. A full beam replacement is not required for an isolated failure.

WLL (also called Safe Working Load) is the maximum load a rigging component is authorized to lift under normal working conditions, accounting for the safety factor from the breaking strength.

A standard choker hitch reduces the rated capacity of a wire rope sling to 75% of its vertical rating — a 25% reduction — when the angle of choke is 120° or greater, due to the bending and pinching of the rope at the choke point (10,000 kg × 0.75 = 7,500 kg). At choke angles below 120° the capacity is reduced further.

Each sling carries half the load adjusted for angle. Half load = 2,000 kg. At 60° from horizontal, efficiency factor = 0.866. Leg tension = 2,000 / 0.866 ≈ 2,310 kg.

Taglines allow workers to guide and control a suspended load from a safe distance, preventing rotation and swing without placing workers directly under or near the load.

ASME B30.2 and most jurisdictional codes specify removal when there are 10+ randomly distributed broken wires in one lay length, or 5+ in a single strand. Visual inspection must also check for kinking, corrosion, and reduction in diameter.

The standard minimum D:d ratio for wire rope on a sheave is 26:1 for 6×19 construction and varies by rope construction. Using smaller sheaves causes excessive bending fatigue and reduces rope life.

The saddle (not the U-bolt) must bear on the live rope end because the U-bolt creates a stress concentration that would damage the load-bearing rope. "Never saddle a dead horse" — saddle on live end, U-bolt on dead end.

Screw-pin shackles can be assembled and disassembled quickly without tools, making them the correct choice for temporary or frequently changed rigging configurations. The other options are incorrect: screw-pin shackles should NOT be used in applications where the pin can rotate or unscrew under load (such as running rigging or slings that rotate) — bolt-type (cotter-pin) shackles are required there. Screw-pin shackles are not rated higher than bolt-type shackles of the same size; they are simply easier to open and close. For permanent installations or overhead lifts with load movement, always use bolt-type shackles with cotter pins.

When the CG is offset, the load tilts toward the heavier side. The sling leg closer to the CG — the one over the heavier end — carries a disproportionately higher load, which must be accounted for in sling selection.

The universal crane signal for STOP is arm extended horizontally with palm facing down, moved side to side. EMERGENCY STOP uses both arms in this position.

Two-blocking occurs when the hook block rises and contacts the boom tip sheave block or lower load block assembly. The resulting shock load can snap the rope or cause the load to fall — a catastrophic failure.

Synthetic slings are removed from service for any cuts or tears that penetrate fibres, acid or caustic burns, heat damage above 90°C, loss of more than 10% of sling width, distorted hardware, or missing/illegible capacity tags.

Each sling leg carries half the load but at 45°, the tension increases. Leg tension = (Total load / 2) ÷ sin(45°) = 4,000 ÷ 0.707 ≈ 5,660 kg per sling.

An equalizer beam distributes the load between multiple sling attachment points, controls sling angles to prevent sling angle problems, and prevents horizontal compressive forces from being transmitted into the load.

The rigging crew (foreman/competent rigger) and the ironworker in charge of the lift, in coordination with the site supervisor, are responsible for preparing or implementing the lift plan for critical lifts. The engineer may provide structural input.

Most Canadian OHS regulations and ASME B30 standards specify a minimum safety factor (breaking strength ÷ WLL) of 5:1 for rigging hardware including wire rope, shackles, and hooks.

WLL = Breaking Strength ÷ Safety Factor = 50,000 ÷ 5 = 10,000 kg. The 5:1 safety factor (design factor) is the minimum required by Canadian OH&S regulations and ASME B30 standards for rigging hardware, and it accounts for dynamic loading, shock loading, fatigue, wear, and inspection intervals. Common wrong answers: using 4:1 (which is the factor for some overhead hoisting equipment under specific standards, not general rigging) or 3:1 (which is far too low and not acceptable for any rigging hardware under Canadian codes). Always verify WLL on the component’s tag — never calculate from breaking strength alone without confirming the applicable standard.

IWRC (Independent Wire Rope Core) is a wire rope core made from a separate wire rope instead of fibre. It provides better crush resistance and allows slightly higher WLL compared to a fibre core rope.

Sling leg tension = (Load / number of legs) × (1 / cos θ). θ = 45° from vertical. Tension = (6,000/2) × (1/cos 45°) = 3,000 × 1.414 = 4,243 kg per leg. The load on each sling leg INCREASES as the angle from vertical increases. At 60°, the factor is 2.0 — each leg carries the full load. This is why angles beyond 60° from vertical are generally avoided.

ASME B30.9 discard criteria for 6×19 wire rope: 3 broken wires in one rope lay or 6 in any rope lay length of 6 times the rope diameter. Finding 4 broken wires in one lay exceeds the 3-wire limit — remove from service immediately, cut into short pieces to prevent reuse, and report to the rigger-in-charge. All wires in a sling assembly must remain serviceable — there are no partial-use allowances.

Load chart values are maximums — they MUST NOT be exceeded under any circumstances. Crane load charts already include safety factors per CSA Z150. Exceeding the chart rating voids the chart, creates an unacceptable risk of crane overturning, and is a criminal liability. The lift must be stopped and re-planned: decrease the lift radius (boom in), improve ground bearing with outrigger pads, or bring in a larger crane.

Sharp edges will cut synthetic web slings even at loads well below the WLL. Synthetic slings (nylon, polyester) have no resistance to sharp metal edges. Use edge protection — corner protectors, edge guards, softeners — or switch to chain slings or wire rope when lifting objects with sharp edges. This is not a load-reduction issue — a cut sling fails catastrophically regardless of load.

To balance an uneven lift, move the crane hook attachment (or spreader bar connection point) toward the heavy end — a shorter distance from hook to heavy end balances the lift. With a spreader bar and equal-length slings, the pickup point must align over the centre of gravity for a level lift. Moving the connection toward the heavy end shortens the moment arm on that side, creating balance. A trial lift at low height before full elevation allows safe adjustment.

SMAW (stick) and FCAW (flux-cored) are the standard field welding processes for structural work due to their tolerance for wind, outdoor conditions, and out-of-position welding capability.

CSA W47.1 (Certification of Companies for Fusion Welding of Steel) governs the certification of welding companies — it certifies the company, not individual welders. Certified companies must have qualified welding supervisors, approved welding procedures (WPSs), and a documented quality control system. This is different from: CSA W59 (which governs the design and fabrication requirements for welded steel structures), CSA W178.2 (which certifies individual welding inspectors), and AWS D1.1 (the American Structural Welding Code used as a reference). On a Canadian structural steel project, the fabricator or erector must hold a current CSA W47.1 certification — this is a mandatory contract requirement.

Preheating slows the cooling rate after welding, allowing hydrogen to diffuse out of the HAZ and preventing the formation of hard, brittle martensite microstructures in the HAZ that are susceptible to hydrogen-induced cracking.

A fillet weld is shown as a right triangle on the weld symbol, with the perpendicular leg always on the left and the hypotenuse facing outward (away from the joint). The weld size is shown to the left of the symbol.

The number to the left of the fillet weld symbol indicates the leg size in millimetres (or inches in imperial drawings). A 10 mm fillet weld has legs of 10 mm on each fusion face.

For a standard fillet weld with equal legs, the theoretical throat = leg × sin(45°) = 12 × 0.707 ≈ 8.5 mm. The effective throat is used to calculate weld strength.

Carbon arc gouging uses a carbon electrode and compressed air to melt and blow away metal. It is the standard method for removing defective welds, back-gouging root passes of groove welds for full penetration, and excavating weld repairs.

A CJP weld requires weld metal to completely penetrate the full thickness of the joint, filling the entire cross-section and achieving full fusion. It is required in joints subject to tension, cyclic, or seismic loading.

A flag on the weld symbol reference line indicates a field weld — one that is to be made during erection at the job site, as opposed to a shop weld made during fabrication.

Per AWS D1.1 Table 4.2, for A572 Gr.50 (Group II steel) and material thickness over 38 mm (1.5 in), the minimum preheat temperature is 107°C (225°F).

Porosity is caused by gas trapped in the solidifying weld metal. Moisture and oil on the base metal or electrode coating are the most common sources — they decompose under the arc heat and produce hydrogen and CO gases.

OFC relies on oxidation and only works on ferrous metals (carbon steel). PAC uses an ionized gas jet and works on any conductive metal that OFC cannot cut, including stainless steel, aluminum, and copper alloys.

Undercut is a groove melted into the base metal at the weld toe that is not filled by weld metal. It is caused by excessive heat, amperage, or travel speed melting the base metal at the toe, or an improper electrode angle.

CSA W59 (Welded Steel Construction — Metal Arc Welding) specifies design, fabrication, and erection requirements for welded steel structures in Canada, including joint design, acceptable workmanship, and inspection criteria. It is often confused with: CSA W47.1 (which certifies welding companies — not design requirements), CSA W59 is the structural welding CODE (what must be built and to what standard), while W47.1 is the company CERTIFICATION standard (who is allowed to build it). AWS D1.1 is the equivalent American standard; many Canadian projects reference both. For Red Seal ironworker exam: know that W59 = fabrication and design standard; W47.1 = company certification; W178.2 = inspector certification.

Seismic connections experience large cyclic deformations and must absorb energy through plastic deformation without fracture. Weld metal must meet notch-toughness requirements verified by CVN (Charpy V-notch) impact testing at -29°C or lower to prevent brittle fracture.

Preheat requirements are based on base metal temperature, not ambient air temperature. At 4°C base metal temperature with a 150°C preheat requirement, the joint must be heated to 150°C minimum with a heating torch before striking the arc. Cold steel increases the risk of hydrogen-induced cracking (HIC). Verify with temperature sticks or a contact pyrometer immediately before welding and maintain interpass temperature throughout.

Longitudinal (centreline) cracking shortly after welding indicates hydrogen-induced cracking (HIC). E7018 is a low-hydrogen electrode that must be kept in a rod oven at 120-150°C after opening the package — an electrode left out of the oven absorbs moisture. Moisture absorbed by the flux releases hydrogen into the weld pool; hydrogen migrates to areas of high residual stress (weld centreline) and causes cracking — sometimes hours after welding. Re-dry electrodes at 370°C for 1 hour if moisture absorption is suspected.

Arc blow occurs in DC welding when magnetic fields deflect the arc. Corrective actions: 1) Switch to AC polarity (AC does not produce arc blow). 2) Move the work ground clamp closer to the weld, or place it on both ends. 3) Angle the electrode toward the direction of blow. 4) Weld toward the ground connection. 5) Reduce current. Arc blow is most common at ends of joints and near heavy metal sections.

Column grid lines are imaginary intersecting reference lines (typically numbered 1, 2, 3… in one direction and lettered A, B, C… in the other) that establish the planned column and structural element locations on a structural drawing. They are NOT column centre-lines in the sense of indicating column size or section — they are location references only. Grid line intersections identify each column by coordinates (e.g., Column B-3). This is different from dimension lines (which show actual measurements between members) and elevation marks (which show height). All trades on a project use the same grid reference to coordinate work — so an ironworker, concrete crew, and mechanical contractor all reference Column B-3 the same way.

EL. (Elevation) followed by a number (e.g., EL. 12500) indicates the finished height of that point in millimetres above the project datum — typically the finished first floor (FF) established at EL. 0.000. Elevations above datum are positive; below datum are negative. This is different from: a grid coordinate (which locates a point in plan, not in height), a dimension (which measures distance between two specific points), or a TOS/BOS notation (which is a specific elevation of the top or bottom of a steel member). When setting anchor bolts or erecting columns, always verify the elevation against the structural drawings — not the architectural drawings, which may use a different datum.

Piece marks (or erection marks) are unique identifiers (e.g., C1, B7, G12) assigned to each fabricated steel member in the structural steel package for tracking and erection — correlating shop drawings with fabricated pieces and the erection plan.

CSA metric designation: W-shape, approximately 460 mm nominal depth, 97 kg per lineal metre. This is standard Canadian structural steel notation.

Section cut symbols have two components: the circle/flag at the ends of the cut line, and the number(s) inside refer to the detail number and sheet number where that section view is shown.

The BOM (also called a material list or schedule) is a complete list itemizing every steel member on the drawing with its designation, size, length, quantity, and piece mark — used for procurement and shop fabrication.

4-M20 A325 means 4 bolts of M20 size (20 mm nominal diameter) meeting ASTM A325 high-strength structural bolt requirements.

TOS (Top of Steel) is an elevation reference on structural drawings indicating the height of the top flange of a beam, measured from the project datum. It is used to coordinate with the concrete deck, mechanical, and architectural drawings. Common related notations: BOS (Bottom of Steel — soffit elevation, important for clearance), TOS is NOT the same as finished floor elevation (which is TOS + deck slab thickness + topping if any). Wrong answers often confuse TOS with the beam depth or with the centreline elevation. For steel erection: when setting beam elevation, you level to the TOS — not to the bottom flange or web centreline.

FSBW (Full Strength Butt Weld) or CJP (Complete Joint Penetration) groove weld indicates that the weld must develop the full tensile strength of the connected base metal — the weld is not the weak link. This requires 100% penetration through the joint thickness, usually verified by visual inspection plus UT (ultrasonic testing) or radiography. It is different from: a partial joint penetration (PJP) weld, which does not penetrate the full thickness and has reduced capacity; a fillet weld, which joins members at a surface (no groove); and a plug or slot weld. FSBW/CJP welds are required at moment connections (beam-column moment joints) and splice plates carrying tension — they cost more (more prep, more passes, more inspection) than fillet welds.

The notation means 4 rebar in the group shown, 20M designation (approximately 20 mm diameter in CSA A23.1), spaced 200 mm on centre (O.C. = on centre).

Camber is built into the beam at the fabrication shop, so no field action is required beyond correct orientation. The ironworker must install the beam with the camber (upward bow) oriented correctly — the camber marking (typically a paint mark) faces up.

The north arrow establishes the plan orientation relative to true north or a project north for layout purposes. Ironworkers use this to orient themselves on site and correctly position structural members per the grid layout.

Structural framing plans are typically drawn at 1:50 (showing individual beams) or 1:100 for larger buildings. Connection details may be drawn at 1:10 or 1:5 to show bolt holes and weld sizes clearly.

W-shape designation: W = Wide Flange. First number = nominal depth in mm (310mm). Second number = mass in kg/m (129 kg/m). This is a standard AISC/CISC wide-flange designation used throughout Canadian structural steel practice. The actual depth may vary slightly from nominal. W310×129 is a heavy section used for heavily loaded beams and columns.

A flag symbol (pennant/triangle on the reference line) indicates a field weld in AWS/CWB welding symbol notation. Field welds are performed at the erection site after steel is delivered, not at the fabrication shop where shop welds are completed. The flag at the reference line-tail junction distinguishes site-welded connections from pre-fabricated connections, critical for erection sequencing.

In the CSA metric system, 20M refers to a deformed metric rebar with a nominal diameter of approximately 19.5 mm and a cross-sectional area of 300 mm². Common sizes: 10M (100 mm²), 15M (200 mm²), 20M (300 mm²), 25M (500 mm²), 30M (700 mm²).

Grade 400W rebar has a minimum specified yield strength of 400 MPa and is weldable (the "W" designation). It is the most common structural rebar grade in Canadian construction.

CSA A23.1 requires a minimum 40 mm concrete cover for steel reinforcement in slabs exposed to weather (exterior exposure). Cover protects rebar from corrosion.

A lap splice is an overlapping zone where two bars run parallel: the bar ends overlap by a specified length (development length × splice factor) so that bar forces transfer through bond with the surrounding concrete.

Development length (ld) is the minimum straight embedment length needed for the bar to develop its full yield strength through bond with the concrete. Insufficient development causes bond failure (bar pull-out).

Bar chairs and supports are plastic or metal supports placed under rebar to maintain the required concrete cover by holding the bars at the correct height above the form (distance from bottom of rebar to bottom of slab).

Rebar ties are made from 16 to 16.5 gauge (approximately 1.6 mm diameter) smooth, soft annealed steel wire, twisted with a tier tool. Multiple tie patterns exist for different conditions (snap tie, saddle tie, figure-8 tie).

A standard 90° hook per CSA A23.1: the tail extension beyond the bend is a minimum 12 bar diameters (12db), with inside bend diameter of 6db for 25M and larger bars (3× db minimum bend radius).

CSA A23.1 permits ±10 mm tolerance on effective depth (d) for members ≤200 mm deep, and ±30 mm tolerance on bar length. Clear cover tolerance is typically −5 mm to +10 mm.

The transverse and longitudinal ribs on deformed bar create mechanical interlock with the surrounding concrete, dramatically improving bond strength compared to smooth bars.

Dowel lap splice length is calculated by the engineer based on development length calculations considering bar size, grade, concrete strength, cover, and splice class. Ironworkers must follow the drawings — never assume a standard splice length.

Light surface rust is acceptable and actually improves bond between rebar and concrete. Only heavy, flaking (loose) rust that significantly reduces the bar cross-section must be removed. CSA A23.1 permits light rust.

Stirrups (beams) and ties (columns) resist shear and torsion forces, confine the concrete core to increase ductility, and brace the longitudinal bars against buckling under compression load.

Rebar placement conflicts with dimensions must be reported to the superintendent and engineer — the footing design may have a drawing vs. actual dimension error. A 400mm footing with 75mm bottom cover + 20M bar (19.5mm) + chair height + 20M top bar + 75mm top cover = physical impossibility. This indicates either a footing dimension error, a cover requirement error, or a bar size error in the drawings. NEVER reduce cover or eliminate reinforcement without engineering direction.

Top reinforcement at column supports resists the hogging bending moment (negative moment) where the top fiber is in tension. Placing these bars at the bottom reverses the reinforcement — the top fiber has no tension reinforcement at the critical moment location. Concrete cannot carry tension, so the slab is effectively unreinforced at the most critical stress location, leading to cracking and potential failure at the supports under service and live load.

Most Canadian provincial OHS regulations require fall protection for ironworkers when working at heights of 3 m (10 ft) or more. Some jurisdictions require protection at lower heights.

A PFAS has three essential components: (1) full-body harness, (2) connecting means (lanyard, self-retracting lifeline, rope grab + lifeline), and (3) an anchor point with sufficient strength.

CSA Z259.16 and most OHS regulations require PFAS anchors to withstand 22.2 kN (5,000 lbf) per attached worker. This equals the OSHA standard and ensures the anchor can survive worst-case fall arrest forces.

A CDZ is a designated zone with specific dimension, positioning, and monitoring requirements (maximum 90 feet/27 m wide, with a CDZ monitor assigned) where ironworkers placing decking are exempt from PFAS requirements due to the nature of the work. Specific regulatory requirements must be met.

PFAS components must be inspected before every use for cuts, fraying, corroded hardware, and proper fit. After a fall event, the harness must be removed from service and inspected by a competent person before any reuse.

Fall clearance = lanyard length (1.8 m) + deceleration distance (1.07 m) + D-ring height (1.5 m) + safety factor (1.2 m) = 5.57 m minimum clearance below anchor.

CSA Z259.11 and most OHS regulations limit free fall in a PFAS to 1.2 m (4 ft) for shock-absorbing lanyards. Positioning the anchor above the D-ring minimizes free fall distance.

An SRL pays out and retracts like a tape measure. In a fall, the rapid pull engages an internal braking mechanism that locks automatically, stopping the fall within milliseconds — limiting free fall to less than 0.6 m and reducing peak arrest force compared to a conventional lanyard.

Per OSHA 1926.502 and equivalent Canadian standards, safety nets must extend at least 2.4 m (8 ft) beyond the edge for drops of 6 m or less, 3 m for drops 6–12 m, and 3.6 m beyond for drops over 12 m.

100% tie-off means continuous connection — the ironworker must have at least one PFAS connection at all times, including while moving or transitioning their tie-off point. A double-lanyard or SRL with a second connection allows transitioning without a gap.

All PFAS components subjected to fall arrest forces must be removed from service. Internal damage not visible externally may have occurred. Only a competent person can return equipment to service after inspection.

Horizontal lifelines with small sag create very high anchor forces due to geometry. With 0.3 m sag over 5 m (half span), the horizontal tension ≈ (W × L)/(4 × sag) = (980 × 5)/(4 × 0.3) ≈ 4,080 N per side — more than 4× the worker weight. This is why HLL anchors require engineered design.

Fall protection must be maintained continuously — never remove a guardrail without equivalent alternate protection already in place; doing so violates provincial OH&S regulations. Options when tie-off points are unavailable above: 1) Safety net below the work level (pre-installed). 2) Positioning device with secondary restraint, or a personnel platform with guardrails. 3) Repositioning to access an available anchor. 4) Install a temporary structural anchor before removing the guardrail. "Less than 5 minutes" is never a valid exception.

SRL total fall distance is not zero. An SRL allows 0.3-0.6m of free fall before locking, plus 0.6-0.9m of deceleration distance during arrest, plus 1.5-1.8m of suspended body height below the anchor. Total clearance required: approximately 1.8-2.4m below the anchor point. At 5m above the lower level, there is sufficient clearance. Always verify clearance before using an SRL.

Decking bundles do NOT qualify as CDZ barriers. CDZ conditions (per provincial OH&S regulations and OSHA 1926 Subpart R): 1) Only decking work is performed. 2) Employees stay back 3m from edge unless using PFAS. 3) Decking is not used as a barrier (bundles shift and are removed). 4) A competent person monitors the zone. Decking bundles appear substantial but are not approved CDZ barriers — they move and are intentionally removed.

An ironworker machine is a multi-function hydraulic bench-top or freestanding machine used in fabrication shops and on site for shearing plate, punching bolt holes, notching angle iron, and bending bar stock.

A drift pin is only a tapered alignment tool for bolt holes. A spud wrench combines a wrench (typically open-end or box) on one end with a tapered shank for alignment on the other, allowing both alignment and bolt tightening in one tool.

Hydraulic tensioners apply direct tensile load to the bolt by pulling the threaded end rather than applying torque, eliminating the torque-to-tension variability that comes from lubrication, thread condition, and technique. This achieves more consistent and accurate pretension.

Equipment WLL ratings must never be exceeded. The rated capacity applies regardless of load speed, number of workers, or direction of use. Overloading can cause sudden failure without warning.

Beam clamps attach to a beam flange by clamping action, providing a temporary rigging point for hooks, slings, and blocks — for hoisting, pulling, or hanging equipment without welding, drilling, or otherwise permanently modifying the beam.

A burning bar (thermic lance) uses a steel tube packed with metal wires and fed with oxygen. It burns at over 5,000°C, cutting through extremely hard materials that conventional cutting cannot handle — hardened steel, concrete, and even rock — used for emergency cutting and demolition.

A builder's level (optical or laser) establishes and verifies a horizontal datum plane across the site. It is used to set column base plate elevations, check beam levelness, and verify floor deck elevations.

Impact wrenches can over-torque and over-tension high-strength bolts if not controlled. For snug-tight installation, the tool must be set or adjusted so it stops after achieving snug. Final tensioning requires a calibrated method (turn-of-nut, TC bolt, DTI, or calibrated torque).

Pre-use inspection of rigging hardware is mandatory. Visually inspect for cracks, deformation (hooks opening, shackle bowing), corrosion reducing cross-section, missing or illegible load ratings, and pin security — and verify the WLL is adequate for the lift.