Washington Administrative Code › Title 296 - Labor and Industries, Department of › Chapter 296-874 - Scaffolds › Section 296-874-099 - Definitions

Current through Register Vol. 24-14, July 15, 2024
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.