Red Seal Boilermaker key terms

A written authorization issued before welding, cutting, or grinding begins in a plant area, confirming fire hazards are controlled, combustibles removed, and a fire watch assigned for the task duration.

A designated person who stays at the hot work site during and after the task, watching for smouldering material and ready to sound alarm or extinguish fire with provided equipment.

The controlled procedure for entering a tank, vessel, or pit with limited access and poor ventilation, requiring atmospheric testing, a standby attendant, rescue plan, and entry permit.

Measuring oxygen content, flammable gases, and toxic vapours inside a space before entry and periodically during work, using calibrated instruments to confirm the space is safe.

An energy control procedure in which switches, valves, and blocks are locked and tagged by each worker so equipment cannot be started or pressure released during maintenance or repair.

Physically separating a machine or system from all energy sources, including electrical, pneumatic, hydraulic, thermal, and stored mechanical energy, before work begins on it.

Worn gear such as helmet, safety glasses, hearing protection, gloves, respirator, and flame-resistant clothing that reduces injury exposure when engineering controls cannot remove the hazard.

Selection, fit testing, and use of respirators to protect against fumes, dust, and oxygen-deficient atmospheres; includes cartridge, supplied-air, and self-contained breathing apparatus types.

A drawing method showing an object from multiple views arranged in a fixed relationship, allowing fabricators to read true lengths and shapes of features on a component.

A drawing convention in which the object sits between viewer and plane, so the top view appears below the front view and the left-side view appears on the right.

A drawing convention in which the projection plane sits between viewer and object, so the top view appears above the front view and the right-side view appears to the right.

The actual size of a line or edge shown in a view where it is parallel to the projection plane; found by auxiliary view or rotation when the line is inclined.

A projected view taken from a direction perpendicular to an inclined surface, used to reveal that surface's true shape or the true length of an inclined edge.

The unfolded, flat pattern of a three-dimensional shape, showing the exact outline and bend lines needed to cut and form plate or sheet into the finished component.

A pattern method for prisms and cylinders where element lines are drawn parallel and projected to a stretch-out line, giving the pattern length equal to the circumference.

A pattern development method that divides a surface into a series of adjacent triangles, finds each side's true length, and assembles them to form the flat pattern.

The length of material consumed by a bend along its neutral axis, added to flat-pattern dimensions so the formed part reaches the required finished size.

The amount subtracted from the sum of outside dimensions to obtain the correct flat length, accounting for material stretched and compressed through the bend radius.

The layer within bent material that neither stretches nor compresses; its location shifts toward the inside of the bend as the bend radius becomes tighter.

The ratio locating the neutral axis relative to material thickness, used in bend allowance formulas and varying with material type, radius, and forming method.

The elastic recovery of metal after forming force is released, causing the part to open slightly; compensated by overbending or by adjusting the forming setup.

A written document listing the variables, such as process, joint design, filler metal, preheat, and current range, that a welder follows to produce a qualified weld.

The documented test results proving that a weld procedure specification produces sound welds; it records actual variables used and mechanical test outcomes.

Testing of an individual welder's skill on a specified joint and process to certify they can deposit welds meeting the required standard within a qualified range.

Heating base metal before welding to slow cooling, drive off moisture, and reduce cracking risk in thick sections or crack-sensitive steels such as high-carbon and alloy grades.

The temperature of the weldment between passes, kept within a specified maximum or minimum to control cooling rate, toughness, and distortion.

A discontinuity such as porosity, slag inclusion, lack of fusion, undercut, or crack that makes a weld fail to meet acceptance criteria.

The angle between a sling leg and the horizontal, which determines the tension in each leg; shallower angles increase leg load and reduce rated capacity.

A multiplier applied to load weight to find sling leg tension, equal to load divided by the number of legs times the length-to-height ratio of the sling.

The maximum load a sling, shackle, hoist, or crane may carry under stated conditions, as marked by the manufacturer and reduced for angle, wear, or configuration.

The point where an object's weight is balanced; the hook must be positioned above it so the load lifts level and does not tilt or swing.

The highest internal pressure a pressure vessel or boiler may legally operate at, established from design thickness, material strength, and joint efficiency at design temperature.

A factor below one applied in pressure-vessel shell calculations to account for strength lost at welded seams, based on the type and extent of examination of the joint.

A pressure test filling a vessel or piping system with water and raising pressure above design to prove strength and tightness before service.

A pressure tightness test using air or gas, permitted only where hydrostatic testing is impractical and carried out with strict exclusion zones because stored energy is high.

A spring-loaded valve that opens automatically at a set pressure to release steam or gas and protect a boiler or vessel from overpressure.

A joint connecting two column sections end to end, transferring axial load and moment through bearing, welds, or bolted plates detailed on the erection drawing.

A steel plate under a column that spreads the column load over a larger concrete area, positioned and levelled on anchor bolts during erection.

A threaded rod cast into concrete foundation to hold down a base plate or structural member, set to template so it aligns with the fabricated hole pattern.

A site plan showing member marks, piece locations, bolt and weld requirements, and sequence for assembling structural steel in the field.

A wall-thickness designation for pipe of a given nominal size; higher schedule numbers mean thicker walls and higher pressure ratings for the same diameter.

A dimensionless size label for pipe that does not equal the actual outside or inside diameter for most sizes; used together with schedule to specify pipe fully.

A piping drawing showing a line in three dimensions with dimensions, fittings, valves, and flow direction, used to plan fabrication and field installation.

A mechanized process where a welding head travels around a fixed pipe joint, giving consistent penetration and bead profile in sanitary and high-purity piping.

Inspection methods such as radiography, ultrasonic, magnetic particle, dye penetrant, and visual that reveal defects without damaging the component being inspected.

A non-destructive method passing X-rays or gamma rays through a weld onto film or a detector, producing an image that reveals internal porosity, slag, and cracks.

A non-destructive method sending high-frequency sound waves into material and reading reflected echoes to locate internal flaws, laminations, and thickness loss.

A surface and near-surface method magnetizing ferromagnetic steel and applying iron particles that gather at discontinuities, revealing cracks and laps.

A surface method applying a coloured or fluorescent liquid that seeps into open defects, then drawing it out with developer to show cracks on any non-porous material.