Osha.gov ➔ Scaffolding eTool

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Scaffolding types

Source: https://www.osha.gov/SLTC/etools/scaffolding/glossary.html (retrieved on 2020-10-26)

Scaffolding Home ➔ Glossary

Adjustable suspension scaffold:

A suspension scaffold equipped with a hoist(s) that can be operated by an employee(s) on the scaffold.

Angulated roping:

A system of platform suspension in which the upper wire rope sheaves or suspension points are closer to the plane of the building face than the corresponding attachment points on the platform, thus causing the platform to press against the face of the building.

Bearer (putlog):

A horizontal transverse 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 suspension scaffold consisting of a seat or sling designed to support one employee in a sitting position.

Body belt (safety belt):

A strap with means both for securing it about the waist and for attaching it to a lanyard, lifeline, or deceleration device.

Body harness:

A design of straps which may be secured about the employee in a manner to distribute the fall-arrest forces over at least the thighs, pelvis, waist, chest, and shoulders, with means for attaching it to other components of a personal fall arrest system.

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.

Carpents' bracket scaffold:

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

Catenary scaffold:

A suspension 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.

Chimney hoist:

A multi-point adjustable suspension scaffold used to provide access to work inside chimneys. (See "Multi-point adjustable suspension scaffold".)

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 crawling boards.

Competent person:

One who is capable of identifying existing and predictable hazards in the surroundings or working conditions which are unsanitary, hazardous, or dangerous to employees, and who has authorization to take prompt corrective measures to eliminate them.

Continuous run scaffold (Run scaffold):

A two-point or multi-point adjustable suspension scaffold constructed using a series of interconnected braced scaffold members or supporting structures erected to form a continuous scaffold.

Coupler:

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

Crawling board (chicken ladder):

A supported scaffold consisting of a plank with cleats spaced and secured to provide footing, for use on sloped surfaces such as roofs.

Deceleration device:

Any mechanism, such as a rope grab, rip-stitch lanyard, specially woven lanyard, tearing or deforming lanyard, or automatic self-retracting lifeline lanyard, which dissipates a substantial amount of energy during a fall arrest or limits the energy imposed on an employee during fall arrest.

Double pole (independent pole) scaffold:

A supported scaffold consisting of a platform(s) 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 designs, materials, or methods to protect against a hazard which the employer can demonstrate will provide an equal or greater degree of safety for employees than the methods, materials, or designs specified in the standard.

Exposed power lines:

Electrical power lines which are accessible to employees and which are not shielded from contact. Such lines do not include extension cords or power tool cords.

Eye or Eye splice:

A loop with or without a thimble at the end of a wire rope.

Fabricated decking and planking:

Manufactured platforms made of wood (including laminated wood and solid sawn wood planks), metal, or other materials.

Fabricated frame scaffold (tubular welded frame scaffold):

A scaffold consisting of a platform(s) supported on fabricated end frames with integral posts, horizontal bearers, and intermediate members.

Failure:

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

Float (ship) scaffold:

A suspension 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 to lower levels.

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 suspension 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-sized, 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, systems 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 kept erect by tilting it toward and resting it against a building or structure.

Lifeline:

A component consisting of a flexible line that connects to an anchorage at one end to hang vertically (vertical lifeline), or that connects to anchorages at both ends to stretch horizontally (horizontal lifeline), and which serves as a means for connecting other components of a personal fall arrest system to the anchorage.

Longitudinal bracing:

Bracing parallel to the long side of the scaffold, so the X runs the same direction as the long side of the scaffold.

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' multi-point adjustable suspension scaffold:

A continuous-run suspension 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.

Mobile scaffold:

A powered or unpowered, portable, caster, or wheel-mounted supported scaffold.

Multi-level suspended scaffold:

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

Multi-point adjustable suspension scaffold:

A suspension scaffold consisting of a platform(s) suspended by more than two ropes from overhead supports and equipped with a means to raise and lower the platform to desired work levels. Such scaffolds include chimney hoists.

Needle beam scaffold:

A platform suspended from needle beams.

Open sides and ends:

The edges of a platform that are more than 14 inches (36 cm) away horizontally from a sturdy, continuous, vertical surface (such as a building wall) or a sturdy, continuous horizontal surface (such as a floor), or a point of access. Exception: For plastering and lathing operations the horizontal threshold distance is 18 inches (46 cm).

Outrigger:

The structural member of a supported scaffold used to increase the base width of a scaffold in order to provide support for and increased stability of the scaffold.

Outrigger beam (Thrustout):

The structural member of a suspension 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 (thrustouts) projecting beyond the wall or face of the building or structure, the inboard ends of which are secured inside the building or structure.

Overhand bricklaying:

The process of laying bricks and masonry units such that the surface of the wall to be jointed 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.

Personal fall-arrest system:

A system used to arrest an employee's fall. It consists of an anchorage, connectors, a body belt, or body harness and may include a lanyard, deceleration device, lifeline, or combinations of these.

Platform:

A work surface 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 pole scaffold".)

Power-operated hoist:

A hoist powered by other than human energy.

Pump jack scaffold:

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

Qualified:

One who, by possession of a recognized degree, certificate, or professional standing, or who by extensive knowledge, training, and experience, has successfully demonstrated the ability to solve or resolve problems related to the subject matter, work, or project.

Rated load:

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

Repair bracket scaffold:

A supported scaffold consisting of a platform supported by brackets which 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 rooftop supported scaffold consisting of a platform resting on angular-shaped supports.

Runner (ledger or ribbon):

The lengthwise horizontal spacing or bracing member which may support the bearers.

Scaffold:

Any temporary elevated platform (supported or suspended) and its supporting structure (including points of anchorage), used for supporting employees or materials or both.

Self-contained adjustable scaffold:

A combination supported and suspension scaffold consisting of an adjustable platform(s) mounted on an independent supporting frame(s) not a part of the object being worked on, and which is equipped with a means to permit the raising and lowering of the platform(s). Such systems include rolling roof rigs, rolling outrigger systems, and some masons' adjustable supported scaffolds.

Shore scaffold:

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

Single-point adjustable suspension scaffold:

A suspension 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 a platform(s) 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 and 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.

Static lines:

Separate ropes secured at their top and bottom ends closer to the plane of the building face than the outermost edge of the platform. By drawing the static line taut, the platform is drawn against the face of the building.

Step, platform, and trestle ladder scaffold:

A platform resting directly on the rungs of step ladders or trestle ladders.

Stilts:

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

Stonesetters' multi-point adjustable suspension scaffold:

A continuous-run suspension scaffold designed and used for stonesetters' operations.

Supported scaffold:

One or more platforms supported by outrigger beams, brackets, poles, legs, uprights, posts, frames, or similar rigid support.

Suspension scaffold:

One or more platforms suspended by ropes or other non-rigid means from an overhead structure(s).

System scaffold:

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

Tank builders' scaffold:

A supported scaffold consisting of a platform resting on brackets that are either directly attached to a cylindrical tank or attached to devices that are attached to such a tank.

Tenon:

A projecting member in a piece of wood or other material for insertion into a mortise to make a joint. [View image]

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 and is used in residential construction for setting trusses.

Transverse bracing:

Bracing at right angles to the long side of the scaffold, so the X is in the interior scaffold space, between parallel uprights.

Tube and coupler scaffold:

A supported or suspended scaffold consisting of a platform(s) supported by tubing, erected with coupling devices connecting uprights, braces, bearers, and runners.

Tubular welded frame scaffold:

(See "Fabricated frame scaffold".)

Two-point suspension scaffold (swing stage):

A suspension scaffold consisting of a platform supported by hangers (stirrups) suspended by two ropes from overhead supports and equipped with 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 catenary scaffolds.

Walkway:

A portion of a scaffold platform used only for access and not as a work level.

Window jack scaffold:

A platform resting on a bracket or jack which projects through a window opening.