NCCER Boilermaker key terms

Clothing and equipment worn to protect the body from hazards such as burns, flying particles, fumes, and electrical shock; includes helmets, eye protection, gloves, and flame-resistant clothing.

A procedure that isolates energy sources and places locks and tags on controls so equipment cannot be started while someone is servicing or repairing it.

An enclosed or partly enclosed area with limited entry and exit, poor natural ventilation, and space too small for continuous occupancy; entry usually requires a permit and atmospheric testing.

A written authorization issued before welding, cutting, grinding, or other spark-producing work begins, confirming fire precautions, area preparation, and a fire watch are in place.

A person assigned to watch for sparks and fire during and after hot work, with authority to stop work and equipment to extinguish fires.

A document supplied with hazardous chemicals that lists hazards, safe handling, protective equipment, first-aid measures, and emergency procedures.

A device installed in oxyfuel hoses or at the regulator that stops a flame from traveling backward into the hose, regulator, or gas supply.

A momentary pop or flashback of flame at the torch tip that goes out or returns to normal, often caused by a dirty tip, wrong pressures, or too-close contact with the work.

An oxyfuel flame with the correct ratio of oxygen to fuel gas, producing a well-defined inner cone and used for most cutting and welding of steel.

A flame with excess fuel gas, shown by a feathery secondary cone around the inner cone; it adds carbon to steel and is used for some hardfacing and special applications.

A flame with excess oxygen, recognized by a shorter inner cone and a hissing sound; it produces a hotter flame and is used mainly for cutting and some brazing.

The width of the cut made by a cutting torch or saw, produced by the removal of material along the cut line.

Slightly curved lines left on the cut face when the cutting oxygen stream lags behind the torch travel; excessive drag indicates poor speed or tip condition.

A filler metal rod or wire that carries current in arc welding and melts into the joint; it may be bare or coated with flux.

The first weld bead placed in a joint, fusing the root faces and forming the foundation for later passes.

The glassy, nonmetallic byproduct that forms on or around a weld from flux and impurities; it must be removed between passes and after welding.

A drawing method that shows a three-dimensional object as separate front, top, and side views arranged at right angles, giving true shapes and sizes.

A pictorial drawing showing an object in three dimensions with three axes equally spaced 120 degrees apart; used to visualize piping and structural layouts.

A section of a drawing that gives identification information such as the drawing number, project name, scale, revisions, and approval signatures.

A list on or with a drawing that identifies parts, descriptions, quantities, sizes, and material specifications needed to build the item.

A standard symbol on a drawing that shows the type, size, length, and location of a weld, often placed on a reference line with an arrow.

A reference line, point, or surface from which measurements are taken during layout so features can be located consistently.

The allowable variation from a stated dimension or specification; it defines the range within which a part is acceptable.

The point where the weight of an object is considered to act; the load must be balanced under the hook to keep a lift stable.

The angle between a sling leg and the horizontal load; as the angle decreases, tension in the sling increases sharply.

A sling arrangement where the sling passes around the load and back through one eye, tightening under load; it grips but reduces capacity.

A sling arrangement where the sling passes under or around the load with both eyes attached to the hook, supporting the load in a cradle.

A U-shaped rigging fitting with a pin or bolt across the opening, used to connect slings, hooks, and loads.

A rope attached to a load to control rotation and sway during lifting, handled by a person who stays clear of the load.

A closed vessel in which water is heated under pressure to produce steam or hot water for process or power use.

A boiler in which water flows inside tubes surrounded by hot combustion gases; it can produce high pressure and large steam flows.

A boiler in which hot gases pass through tubes surrounded by water; it is common for lower-pressure heating and process steam.

The upper pressure vessel of a watertube boiler where steam separates from water and collects before leaving the boiler.

A bank of tubes that heats steam above its saturation temperature after it leaves the drum, improving efficiency and reducing condensation in turbines.

A pressure-relief device that opens automatically at a set pressure to release steam or gas and prevent overpressure of the vessel.

A pressure test in which a vessel is filled with water and pressurized above its design pressure to check for leaks and structural strength.

A heat exchanger with a cylindrical shell and a bundle of tubes; one fluid flows through the tubes while another flows across them inside the shell.

A thick plate with holes that holds the ends of heat exchanger tubes and separates the tube-side fluid from the shell-side fluid.

A plate inside a heat exchanger shell that directs the shell-side fluid across the tubes to improve heat transfer and support the tube bundle.