Supported scaffolds consist of one or more platforms supported by legs, outrigger beams, brackets, poles, uprights, posts, frames, or similar rigid support. 1926.451(b)
Fabricated frame scaffolds are the most common type of scaffold because they are versatile, economical, and easy to use. They are frequently used in one or two tiers by residential contractors, painters, etc., but their modular frames can also be stacked several stories high for use on large-scale construction jobs. More information on this scaffold.
Tube and coupler scaffolds are so-named because they are built from tubing connected by coupling devices. Due to their strength, they are frequently used where heavy loads need to be carried, or where multiple platforms must reach several stories high. Their versatility, which enables them to be assembled in multiple directions in a variety of settings, also makes them hard to build correctly.More information on this scaffold.
Pole scaffolds are a type of supported scaffold in which every structural component, from uprights to braces to platforms, is made of wood. OSHA has standards for two kinds: single-pole, which are supported on their interior side by a structure or wall, and double-pole, which are supported by double uprights independent of any structure.
Pole scaffolds are old-fashioned and are rarely used today because they have to be built from scratch and cannot be reused. More information on this scaffold.
Mast climbing supported scaffolds (mast climbers) carry much heavier loads than traditional scaffolding and are used to position personnel and the necessary tools, equipment, and materials needed to perform work at great heights.
Mast climbers can be free-standing or tied to a structure at intervals for stability at increased heights. The mast may be supported on a stationary base, or for some projects that are lower, on a mobile base. Mast climbers can reduce the potential for shoulder and lower back injuries because they can be adjusted to optimized working heights. Proper platform positioning reduces material handling hazards and fatigue and improves productivity. More information on this scaffold.
Click on the image below to see the mast climber scaffold that was involved in a multiple-fatality accident.
A ladder jack scaffold is a system designed to perform activities, such as: installing building exteriors, trim, and finishes. Contractors widely use ladder jack scaffolds because of their cost effectiveness, portability, and quick erection and dismantling procedures, as well as their adaptability for use in narrow spaces at construction worksites. More information on this scaffold.
Pump jacks are uniquely designed scaffolds consisting of a platform supported by movable brackets on vertical poles. The brackets are designed to be raised and lowered in a manner similar to an automobile jack. Pump jacks are appealing for certain applications because they can be easily adjusted to variable heights, and are relatively inexpensive. More information on this scaffold.
In August, 1992, two workers were erecting an aluminum pump jack scaffold. As they were raising the second aluminum pole, the pole apparently contacted an overhead power line. The pole being raised was 29 feet 10 inches long and the line was 28 feet 10 inches high. The line was approximately 11 feet from the house. One employee died and the other suffered severe burns and was hospitalized. The surviving employee noted that he thought they had enough room to work around the power lines, which were not de-energized or shielded.
Mobile scaffolds are a type of supported scaffold set on wheels or casters. They are designed to be moved easily and are commonly used for things like painting and plastering, where workers must frequently change position. More information on this scaffold.
Many scaffold types regulated by OSHA standards are rarely used, and designed for a very narrow and specific range of applications. Specialty scaffolds include:
Click on the button to see the various types of specialty scaffolds.
Supported scaffolds' poles, legs, posts, frames, and uprights must bear on base plates and mud sills, or other adequate firm foundation. 1926.451(c)(2)(i) and (ii)
Supported scaffolds with a height to base width ratio of more than 4:1 must be restrained by guying, tying, bracing, or an equivalent means. 1926.451(c)(1)
Either the manufacturers' recommendation or the following placements must be used for guys, ties, and braces:
Forklifts can support platforms only when the entire platform is attached to the fork and the forklift does not move horizontally when workers are on the platform. 1926.451(c)(2)(v)
Front-end loaders and similar equipment can support scaffold platforms only when they have been specifically designed by the manufacturer for such use. 1926.451(c)(2)(iv)
OSHA prohibits using "makeshift" objects (e.g., saw horses, buckets, milk crates, concrete blocks, etc.) to increase the working height of a scaffold, because an unstable platform increases the likelihood of collapse or a fall.
Stilts means a pair of poles or similar supports with raised footrests, used to walk above the ground or above the working surface. Stilts are often used for sheetrock installation and for painting and decorating and other tasks requiring walking mobility with increased height/reach. They may also be used on a large-area scaffold. When a guardrail system is used, the guardrail height must be increased in height equal to the height of the stilts. The manufacturer must approve any alterations to the stilts. 1926.452(v)
Note: A large area scaffold consists of a pole, tube and coupler systems, or a fabricated frame scaffold erected over substantially the entire work area. 1926.451(b)
Employers must provide access when the scaffold platforms are more than 2 feet (0.6 meters) above or below a point of access. 1926.451(e)(1)
Direct access is acceptable when the scaffold is not more than 14 inches (36 centimeters) horizontally and not more than 24 inches (61 centimeters) vertically from the other surfaces. 1926.451(e)(8)
The standard prohibits the use of crossbraces as a means of access. 1926.451(e)(1)
Several types of access are permitted:
Access While Erecting and Dismantling Supported Scaffolds?
Employees erecting and dismantling supported scaffolding must have a safe means of access provided when a competent person has determined the feasibility and analyzed the site conditions. 1926.451(e)
Shore and lean-to scaffolds are strictly prohibited. 1926.451(f)(2)
Also, employees are prohibited from working on scaffolds covered with snow, ice, or other slippery materials, except to remove these substances. 1926.451(f)(8)
The shore scaffold in the image to the right is not permitted to be used per OSHA or ANSI. In this picture, the workers have a shore scaffold on top of another shore scaffold. Access is unsafe both from above and below. The only thing holding this scaffold up is the DUMPSTER!
Scaffolds must not be erected, used, dismantled, altered, or moved such that they or any conductive material handled on them might come closer to exposed and energized power lines than as follows: 1926.451(f)(6)
Click on the button to see the table of insulated and non-insulated clearance distances.
Guardrails must be installed on all scaffold platforms in accordance with OSHA 1910.451 and at least consist of top rails, midrails and toeboards.
Workers on suspended scaffolds must use a fall protection system to protect them against scaffold failure. This system will usually consist of a full body harness, lanyard, rope grab, independent vertical lifeline and an independent lifeline anchorage. Remember, fall protection is only as good as its anchorage. The anchorage points are independent points on structures where lifelines are securely attached. These points must be able to support at least 5,000 pounds per employee.
Workers and others located at lower levels need to be protected from objects falling off scaffolds using the following methods:
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This SW MGT video gives examples of fall hazards while working on scaffolds.