Adjustable suspension scaffold. A suspended scaffold equipped with one or more hoists that can be operated by employees on the scaffold.

Bearer. A horizontal scaffold member (which may be supported by ledgers or runners) upon which the scaffold platform rests and which joins scaffold uprights, posts, poles, and similar members.

Boatswain's chair. A single-point adjustable suspended scaffold consisting of a seat or sling designed to support one employee in a sitting position.

Brace. A rigid connection that holds one scaffold member in a fixed position with respect to another member, or to a building or structure.

Bricklayers' square scaffold. A supported scaffold composed of framed squares which support a platform.

Carpenters' bracket scaffold. A supported scaffold consisting of a platform supported by brackets attached to building or structural walls.

Catenary scaffold. A suspended scaffold consisting of a platform supported by two essentially horizontal and parallel ropes attached to structural members of a building or other structure. Additional support may be provided by vertical pickups.

Cleat. A structural block used at the end of a platform to prevent the platform from slipping off its supports. Cleats are also used to provide footing on sloped surfaces such as access ramps.

Competent person. Someone who:

(a) Is capable of identifying existing and predictable hazards in the surroundings or working conditions which are unsanitary, hazardous, or dangerous to employees; and

(b) Has the authority to take prompt corrective measures to eliminate them.

Coupler. A device for locking together the tubes of a tube and coupler scaffold.

Double-pole (independent pole) scaffold. A supported scaffold consisting of one or more platforms resting on cross beams (bearers) supported by ledgers and a double row of uprights independent of support (except ties, guys, braces) from any structure.

Equivalent. Alternative design, material, or method to protect against a hazard. You have to demonstrate that it provides an equal or greater degree of safety for employees than the method, material, or design specified in the rule.

Exposed power lines. Electrical power lines which are accessible to and may be contacted by employees. Such lines do not include extension cords or power tool cords.

Eye or eye splice. A loop at the end of a wire rope.

Fabricated frame scaffold (tubular welded frame scaffold). A scaffold consisting of platforms supported on fabricated frames with integral posts, horizontal bearers, and intermediate members.

Failure. Load refusal, breaking, or separation of component parts. Load refusal is the point where the ultimate strength is exceeded.

Float (ship) scaffold. A suspended scaffold consisting of a braced platform resting on two parallel bearers and hung from overhead supports by ropes of fixed length.

Form scaffold. A supported scaffold consisting of a platform supported by brackets attached to formwork.

Guardrail system. A vertical barrier consisting of, but not limited to, toprails, midrails, and posts, erected to prevent employees from falling off a scaffold platform or walkway.

Handrails (ladder stands). A rail connected to a ladder stand running parallel to the slope and/or top step.

Hoist. A manual or power-operated mechanical device to raise or lower a suspended scaffold.

Horse scaffold. A supported scaffold consisting of a platform supported by construction horses (saw horses). Horse scaffolds constructed of metal are sometimes known as trestle scaffolds.

Independent pole scaffold. (See double-pole scaffold.)

Interior hung scaffold. A suspended scaffold consisting of a platform suspended from the ceiling or roof structure by fixed length supports.

Ladder jack scaffold. A supported scaffold consisting of a platform resting on brackets attached to ladders.

Ladder stand. A mobile, fixed-size, self-supporting ladder consisting of a wide flat tread ladder in the form of stairs.

Landing. A platform at the end of a flight of stairs.

Large area scaffold. A pole scaffold, tube and coupler scaffold, system scaffold, or fabricated frame scaffold erected over substantially the entire work area. For example: A scaffold erected over the entire floor area of a room.

Lean-to scaffold. A supported scaffold which is kept erect by tilting it toward and resting it against a building or structure.

Ledger. (See runner.)

Lower levels. Areas below the level where the employee is located and to which an employee can fall. Such areas include, but are not limited to, ground levels, floors, roofs, ramps, runways, excavations, pits, tanks, materials, water, and equipment.

Masons' adjustable supported scaffold. (See self-contained adjustable scaffold.)

Masons' multipoint adjustable suspension scaffold. A continuous run suspended scaffold designed and used for masonry operations.

Maximum intended load. The total load of all persons, equipment, tools, materials, transmitted loads, and other loads reasonably anticipated to be applied to a scaffold or scaffold component at any one time.

Midrail. A rail, approximately midway between the toprail of a guardrail system and the platform, and secured to the uprights erected along the exposed sides and ends of a platform.

Mobile scaffold. Supported scaffold mounted on casters or wheels.

Multilevel suspended scaffold. A two-point or multipoint adjustable suspension scaffold with a series of platforms at various levels resting on common stirrups.

Multipoint adjustable suspension scaffold. A suspended scaffold consisting of a platform(s) which is suspended by more than two ropes from overhead supports and equipped with means to raise and lower the platform to desired work levels.

Needle beam scaffold. A suspended scaffold which has a platform supported by two bearers (needle beams) suspended from overhead supports.

Outrigger. A structural member of a supported scaffold which increases the base width of a scaffold. This provides support for and increases the stability of the scaffold.

Outrigger beam (suspended and supported). The structural member of a suspended scaffold or outrigger scaffold which provides support for the scaffold by extending the scaffold point of attachment to a point out and away from the structure or building.

Outrigger scaffold. A supported scaffold consisting of a platform resting on outrigger beams which projects beyond the wall or face of the building or structure. The inboard ends of the outrigger beams are secured inside the building or structure.

Overhand bricklaying. The process of laying bricks and masonry so that the surface of the wall is on the opposite side of the wall from the mason, requiring the mason to lean over the wall to complete the work. It includes mason tending and electrical installation incorporated into the brick wall during the overhand bricklaying process.

Platform. A work surface used in scaffolds, elevated above lower levels. Platforms can be constructed using individual wood planks, fabricated planks, fabricated decks, and fabricated platforms.

Pole scaffold. (See single-pole scaffold and double (independent) pole scaffold.)

Pump jack scaffold. A supported scaffold consisting of a platform supported by vertical poles and movable support brackets.

Qualified person. A person who has successfully demonstrated the ability to solve problems relating to the subject matter, work, or project, either by:

(a) Possession of a recognized degree, certificate, or professional standing; or

(b) Extensive knowledge, training and experience.

Rated load. The manufacturer's specified maximum load to be lifted by a hoist or to be applied to a scaffold or scaffold component.

Repair bracket scaffold. A supported scaffold consisting of a platform supported by brackets. The brackets are secured in place around the circumference or perimeter of a chimney, stack, tank, or other supporting structure by one or more wire ropes placed around the supporting structure.

Roof bracket scaffold. A supported scaffold used on a sloped roof. It consists of a platform resting on angular-shaped supports so that the scaffold platform is level.

Runner (ledger). The lengthwise horizontal spacing or bracing member which may support the bearers.

Scaffold. A temporary elevated platform, including its supporting structure and anchorage points, used for supporting employees or materials.

Self-contained adjustable scaffold. A combination supported and suspended scaffold consisting of an adjustable platform mounted on an independent supporting frame, not a part of the object being worked on, which is equipped with a means to raise and lower the platform. Such systems include rolling roof rigs, rolling outrigger systems, and some masons' adjustable supported scaffolds.

Shore scaffold. A supported scaffold which is placed against a building or structure and held in place with props.

Single-point adjustable suspension scaffold. A suspended scaffold consisting of a platform suspended by one rope from an overhead support and equipped with means to permit the movement of the platform to desired work levels.

Single-pole scaffold a supported scaffold. Consisting of platforms resting on bearers, the outside ends of which are supported on runners secured to a single row of posts or uprights, and the inner ends of which are supported on or in a structure or building wall.

Stair tower (scaffold stairway/tower). A tower comprised of scaffold components which contains internal stairway units and rest platforms. These towers are used to provide access to scaffold platforms and other elevated points such as floors and roofs.

Stall load. The load at which the prime mover of a power-operated hoist stalls or the power to the prime mover is automatically disconnected.

Step, platform, and trestle ladder scaffold. A platform resting directly on the rungs of a step, platform, or trestle ladder.

Stilts. A pair of poles or similar supports with raised footrests, used to permit walking above the ground or working surface.

Stonesetters' multipoint adjustable suspension scaffold. A continuous run suspended scaffold designed and used for stonesetters' operations.

Supported scaffold. One or more platforms supported by rigid means such as outrigger beams, brackets, poles, legs, uprights, posts, or frames.

Suspended scaffold. One or more platforms suspended from an overhead structure by ropes or other nonrigid means.

System scaffold. A scaffold consisting of posts with fixed connection points that accept runners, bearers, and diagonals that can be interconnected at predetermined levels.

Toeboard (scaffold). A barrier erected along the exposed sides and ends of a scaffold platform at platform level to prevent material, tools, and other loose objects from falling from the platform.

Top plate bracket scaffold. A scaffold supported by brackets that hook over or are attached to the top of a wall. This type of scaffold is similar to carpenters' bracket scaffolds and form scaffolds.

Tube and coupler scaffold. A scaffold consisting of platforms supported by tubing, erected with coupling devices connecting uprights, braces, bearers, and runners.

Tubular welded frame scaffold. (See fabricated frame scaffold.)

Tubular welded sectional folding scaffold. A sectional, folding metal scaffold either of ladder frame or inside stairway design. It is substantially built of prefabricated welded sections, which consist of end frames, platform frame, inside inclined stairway frame and braces, or hinged connected diagonal and horizontal braces. It can be folded into a flat package when the scaffold is not in use.

Two-point suspension scaffold (swing stage). A suspended scaffold consisting of a platform supported by hangers (stirrups), suspended by two ropes from overhead supports, and equipped with a means to permit the raising and lowering of the platform to desired work levels.

Unstable objects. Items whose strength, configuration, or lack of stability may allow them to become dislocated and shift and therefore may not properly support the loads imposed on them. Unstable objects do not constitute a safe base support for scaffolds, platforms, or employees. Examples include, but are not limited to, barrels, boxes, loose brick, and concrete blocks.

Vertical pickup. A rope used to support the horizontal rope in a catenary scaffold.

Walkway (scaffold). Part of a scaffold used only for access and not as a working level.

Window jack scaffold. A platform resting on a bracket or jack that projects through a window opening.

Work level. The elevated platform, used for supporting workers and their materials.