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  • Scaffold Safety September 2012

    Scaffold Safety

    L O S S C O N T R O L A L E R T

    Scaffolds are useful tools to access elevated work areas. Appearing more stable and providing a larger work platform

    than ladders, they seem to be even easier and safer to use. However, poor set-up and misuse can result in serious work-

    place injury or death. The Occupational Safety and Health Administration (OSHA) reports that:

    17% of all construction related falls resulting in a fatality in-volved a scaffold

    72% of these scaffold accidents were caused by unsafe set-up, use or failure to protect the worker from falling material

    25% of workers injured in scaffold accidents had received no scaffold safety training

    77% of scaffolds were not equipped with guardrails when required

    These findings are neither unusual nor unique. Besides the impact

    these claims have on the cost of insurance, there are also many

    other costs which can significantly impact your business. When you

    consider the cost of replacing damaged equipment, the loss of a

    productive worker, lost production, possible damage to customer

    property, it makes sense to prevent these losses instead of continu-

    ally trying to overcome their costly results.

    This Alert provides some suggested safe practices that may be use-

    ful in preventing scaffold related worker injuries. It does not ad-

    dress all regulatory requirements or best practices.


    There are many different types of scaffolds all designed for specific purposes. Scaffolds generally fall into three catego-


    Supported: Platforms supported by rigid, load bearing members such as poles, legs, frames and outriggers

    Suspended: Platforms suspended by ropes or other non-rigid means from an overhead structure

    Aerial Lifts: Vehicle mounted devices used to get a worker to an elevated position (e.g. cherry pickers or boom trucks)

    Knowing the purpose of these scaffolds will help to select the right one for the job. Once the type of scaffold is deter-

    mined, the next step is to determine the strength needed for the specific tasks.

    In general, all scaffolds, manufactured or constructed, must be able to support their own weight plus four times their maxi-

    mum intended loads. The supporting capability of a scaffold, or its duty rating, is stated in pounds per square foot. There

    are 3 scaffold duty ratings:

    Additionally, key scaffold components such as suspension rope and connecting hardware must be able to support six

    times the maximum intended load.

    OSHA has published scaffold design specifications as part of their 1926.450 scaffold safety regulations. The intent of

    these specifications is to aid in their fabrication. They can also be used to assure that purchased or rented scaffolds meet

    OSHA requirements. The American National Standards Institute (ANSI) has also published design specifications for aerial

    lifts and other mobile elevating scaffolds.

    Duty Rating Capacity (lbs. /sq. ft.)

    Light 25

    Medium 50

    Heavy 75

  • Scaffold Safety September 2012

    E V E R E S T L O S S C O N T R O L A L E R T


    A competent person, an individual that has the skills to identify scaffold safety hazards and has the authority to promptly

    correct or eliminate them, must inspect all scaffolds before each work shift and periodically during their use and after

    each adverse weather event. This individual must supervise all scaffold assemblies, changes, movement, or dismantling.

    Inspections must address all supporting members, anchors, platforms, clearance requirements, and proximity hazards

    such as power lines and fall protection specific to each scaffold type. The inspections also must verify that is the scaffold

    is level and plumb, the base plates are in firm contact with sills, bracing is in place and connected, platforms are fully

    planked, guardrails in place, safe access is provided, it is properly tied or guyed and that there are no overhead obstruc-

    tions within 12 feet.

    Wood planks should be inspected to verify that they are the correct grade and in good condition, straight grained, and free

    from saw cuts, splits and holes.

    When platform height exceeds 4 ft., guard rails are recommended but not required by OSHA. OSHA requires guard rails for

    all platforms 10 ft. or higher. (California requires guardrails for all platforms 7 feet or higher) Guardrails should be in-

    stalled on all open sides and ends. Toe boards, screens or barricades need to be in place to prevent material falling off

    the scaffold and canopies installed to protect scaffold workers from debris falling from above. Safety nets, designed to

    contain materials, tools and equipment should be installed when scaffolds are erected over high worker, pedestrian or

    equipment/material transport traffic areas.

    Scaffolds need to be erected plumb, level, squared and braced to prevent collapse. Mobile scaffolds need to have locka-

    ble and functioning wheels and casters. Non-mobile scaffolds should be anchored in place to prevent movement. Do not

    place footings on soft or frozen ground or resting on blocks. Base plates or screw jacks with base plates must be in firm

    contact with both the sills and the legs of the scaffolding. Compensate for uneven ground with screw jacks with base

    plates. DO NOT USE unstable objects such as blocks, loose bricks, etc.

    Scaffolds must be secured when the height exceeds 4 times the minimum base width. (California requires stability bracing

    when the scaffold height exceeds 3 times the minimum base width).

    Job sites should be inspected to assure ground conditions are able to support the scaffold and for proximity of electric

    power lines, overhead obstructions, wind conditions as well as the need for overhead protection or weather protection

    coverings. For suspended scaffolds, the supporting outrigger beams must be able to support at least 4 times the intended load and

    be attached to the roof, tied to a secure anchorage, or secured with counterweights. The suspension ropes and rigging

    must support at least 6 times the intended load.

    Counterweights made of non-viscous material must be attached to secure and

    strong places on a building so they wont move. Sand or gravel, masonry blocks, or roofing materials cannot be used as a counterweight as these can flow or


    Exhibit C1-3 provides model scaffold inspection checklists. Proper Use and Storage:

    There are many accepted general and specific scaffold safe work practices. This

    Alert is not intended to address all of them but offers a few best practices.

    Scaffolds must be designed by a qualified person and constructed and loaded in

    accordance with that design. A qualified person is one who has sufficient

    knowledge, education, training or experience to solve or resolve scaffold related

    problems. Under certain circumstances, a professional engineer is required to

    design a scaffold.

    If the scaffold is equipped with guardrails by the manufacturer, they should be in

    place at all times regardless of height. Always follow manufacturer instructions

    and warnings! Scaffolds should not be positioned or erected within 10 feet of energized power lines. Work should not be performed

    when platforms are covered by ice or snow. Equipment material or ladders or should not be used on scaffold platforms to

    gain additional height.

    Safe access to the working level, via a ladder or other accepted means, needs to be provided and workers must be re-

    quired to use for access.

    Page 2

    E V E R E S T L O S S C O N T R O L A L E R T

  • Scaffold Safety September 2012

    Page 3

    E V E R E S T L O S S C O N T R O L A L E R T

    Scaffolds equipment and components should be stored in areas which do not expose them to potential damage from ma-terial handling traffic or weather conditions that may weaken or deteriorate them.

    Harnesses and lanyards must be used by aerial lift workers and fall protection must be in place prior to using the lift. Addi-

    tionally, workers should be prohibited from moving the lift vehicle while standing in the basket unless the equipment is

    designed for this purpose.

    Mobile scaffolds should be moved from the bottom. Workers should not be permitted to move or ride on them unless they

    are specifically designed for that purpose or the use has been approved by a competent person.

    The safe working height of mobile scaffolds must not exceed four times the base dimensions unless increased stability is

    provided, such as additional bracing, out rigging, or guy wires. This will help to prevent tip-over.

    Teaching and Enforcing Safe Work Practices:

    Many accidents are caused by the unsafe use of scaffolds. Workers must be trained by a qualified person on the follow-


    Hazard identification & mitigation including falls from scaffolds, struck by falling materials, scaffolding collapse etc.

    Scaffold design and selection

    Proper scaffold use and handling

    Maximum intended loads and how to determine if the task specific loads will exceed this capacity

    Safe erection, dismantling and re-locating or moving scaffolds

    A competent person must train any worker who assembles, takes apart, moves, operates, repairs, maintains, or inspects

    scaffolds. Exhibit