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Scaffolding Safety. Erecting & Dismantling. Introduction. As a person who erects and dismantles scaffolding, your safety - and the safety of those who will work on the scaffold - depends on your ability to closely follow the minimum safety requirements for constructing and using scaffolds. .
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Scaffolding Safety Erecting & Dismantling
Introduction As a person who erects and dismantles scaffolding, your safety - and the safety of those who will work on the scaffold - depends on your ability to closely follow the minimum safety requirements for constructing and using scaffolds.
Introduction The scaffold system you erect will support many workers and allow them to carry out their job functions. How well you follow proper procedures and safe work practices while erecting scaffolds will have a direct affect on their safety. If you have any questions about erecting or dismantling scaffolding, ask your supervisor.
Pre-planning It is important that thorough pre-planning takes place before scaffolding is erected. This should include: • Evaluation and Preparation of the Site • Identification of Any Potential Hazards • Determining the Type of Scaffolding to be Used • Activities to be Performed and their Weight Requirements • Weight Capacity of the Scaffold
Pre-planning Evaluating the Site While evaluating the site there are many factors to consider. There may be a number of steps you will need to take to prepare the site. Some items to check could include:
Pre-planning • Is the surface level and sound? • Can the ground support the scaffold unit? • Are there any unguarded openings or potential underground utility work that may affect the stability of the scaffold?
Pre-planning • Are there any nearby electrical power lines? • If so, can the scaffold be erected while keeping a minimum safe approach distance from the lines? • Can work be performed on the scaffold while maintaining a minimum safe approach distance from the electrical power lines?
Pre-planning • What type of pedestrian, vehicular, or equipment traffic will be in the area? • What type of fall protection will be feasible? • Will safe access while erecting and dismantling the scaffold be feasible? • Will conditions such as high winds, storms, or icy conditions exist?
Scaffolding Inspection To make sure scaffold components are in good working order, carefully inspect all scaffolding parts before and during its erection. A defective or damaged part could affect the integrity of the whole scaffold.
Scaffolding Inspection Items to Check Some areas to inspect include the following: • Are planks and wood components free of splits, rot, burns, warps, splintering, oil, or paint and opaque finishes that could cover potential defects. • Are wood planks scaffold grade? • Are welds and bolted connections in good condition.
Scaffolding Inspection CAUTION! • Any defective parts must not be used. • Any damaged or weakened scaffold part must be immediately repaired or removed from service until it is repaired. • Never risk your safety by using damaged parts.
Load Capacity The load capacity of a scaffold varies, depending on its design and application. General capacity requirements for all scaffolds include:
Load Capacity • The scaffold and each scaffold component must be capable of supporting four times the maximum intended load. This includes all personnel, equipment, and supplies. • Direct connections and counterweights used to balance adjustable suspension scaffolds must be able to resist at least four times the tipping moment of the scaffold, including stall loads.
Load Capacity • All suspension ropes and connecting hardware must be capable of supporting at least six times the maximum intended load. • Scaffolds must be designed by a qualified person, and built and loaded according to that design. • Never overload the scaffold.
Platform Construction The platform surface that supports workers and materials on the scaffold is called planks. Planks are usually made of steel, aluminum, or wood. Wood scaffold planks should be 2 by 10 inches, scaffold plank grade, and stamped by an agency approved by the American Lumber Standards Committee. Any unsafe planks should be removed from service and clearly marked or made unusable.
Platform Construction • When erecting scaffolding it is most important to make sure the first unit of any scaffold is plumb, aligned, and level. • Each platform on all working levels of scaffolds are required to be fully planked or decked, except when used only as walkways or for erecting or dismantling scaffolding.
Platform Construction • The platform and walkway must be at least 18 inches wide. • Install each platform unit (plank, fabricated deck, or fabricated platform) so that the space between planks, and the space between the platform and the uprights, is no more than one inch.
Platform Construction • The front edge of the platform must be no more than 14 inches from the face of the work, unless guardrails are used along the front edge and/or personal fall arrest systems are used. • Never cover wood platforms with opaque finishes (such as paint), except for the edges, which may be covered or marked for identification. • Never intermix scaffold components by different manufacturers, unless a competent person determines they are compatible and the scaffold’s structural integrity is maintained.
Platform Construction • Each end of the platform, unless cleated or restrained by hooks or other means, must extend over the center line of its support at least six inches. • If the platform is 10 feet or less in length, the end cannot extend over its support more than 12 inches. • If the platform is over 10 feet in length, its end cannot extend over the support more than 18 inches.
Platform Construction • When platforms are overlapped to create a long platform, the overlap must occur only over supports and must be at least 12 inches, unless the platforms are restrained to prevent movement. • Each abutted end of a plank must rest on a separate support surface. • When the platform changes direction, any platform that rests on a bearer at an angle other than a right angle must be laid first. Platforms that rest at right angles over the same bearer must be laid second, on top of the first platform.
Supported Scaffolds Supported scaffolds have one or more platforms that are supported by outrigger beams, brackets, poles, legs, uprights, posts, frames, or similar rigid supports. The following are some general requirements for supported scaffolds:
Supported Scaffolds • When using mud sills, the base plates should be attached to it. For added stability, it is recommended the mud sill be one continuous sill under both legs. The sill should extend at least 12 inches beyond the center line of the pole.
Supported Scaffolds • All supported scaffold poles, legs, posts, frames, and uprights must bear on base plates, mud sills, or other firm foundation. • They must also be plumb and braced to prevent swaying and displacement. • Footings must be level, sound, rigid, and capable of supporting the load of the scaffold without settling or displacing.
Supported Scaffolds • Never use cinder blocks, bricks, gravel, loose fill, or other means for leveling uneven surfaces, or providing a foundation for the base plate. • When supported scaffolds have a height-to-base width ratio of more than 4-to-1 (four feet of height for every one foot of width), then guys, ties, or braces must be installed at locations where horizontal members support both inner and outer legs.
Suspension Scaffolds Suspension scaffolds have one or more platforms suspended by ropes or other non-rigid means from an overhead structure. Before the suspension scaffold is used, a competent person must confirm that the supporting surfaces are capable of supporting the loads imposed on them.
Suspension Scaffolds The following are some general requirements for suspension scaffolds: Ropes • NEVER use repaired wire rope as suspension rope. • Ropes need to be inspected by a competent person for defects before each work shift and after any occurrence that could affect a rope’s integrity.
Suspension Scaffolds Hoists • Gasoline-powered equipment and hoists must not be used on suspension scaffolds. • Gears and brakes of power-operated hoists used on suspension scaffolds must be enclosed.
Suspension Scaffolds Support Devices • All suspension scaffold support devices (such as outrigger beams, cornice hooks, and parapet clamps) must rest on surfaces that are capable of supporting four times the load imposed on them. • Two-point and multi-point suspension scaffolds must be tied or otherwise secured to prevent them from swaying if a competent person determines it is necessary. Never use window cleaners’ anchors for this purpose.
Suspension Scaffolds Outrigger Beams • When suspension scaffold outrigger beams are used, they must be restrained to prevent movement. The inboard ends of suspension scaffold outrigger beams must be stabilized by bolts or other direct connections to the floor or roof deck, or by counterweights.
Suspension Scaffolds Counterweights • Never use sand, gravel, or other materials that can be easily dislocated as counterweights. Only objects specifically designed as counterweights must be used. • Counterweights must be secured by mechanical means to the outrigger beams to prevent accidental displacement. • Do not remove the counterweights until the scaffold is disassembled.
Suspension Scaffolds Tiebacks • Outrigger beams that are not stabilized by both bolts or other direct connections to the floor or the roof deck must be secured by tiebacks. • Tiebacks must be equal in strength to the suspension ropes. • Tiebacks must be secured to a structurally sound anchorage on the building or structure. Do NOT use standpipes, vents, or electrical conduits as anchorages.
Access Requirements Many scaffold-related injuries occur while improperly getting on or off platforms. Never jump onto a scaffold.
Access Requirements • When the scaffold platform is more than two feet above or below a point of access, then a portable ladder, stairway, ramp, or other means of access that does not affect the scaffold’s stability must be used. • Never use cross braces to climb onto the scaffold or another level of the scaffold. • Direct access from one scaffold to another can only be used when the scaffold surfaces are not more than 14 inches horizontally and 24 inches vertically from each other.
Access Requirements Portable, Hook-On, and Attachable Ladders • Place hook-on and attachable ladders so their bottom rung is not more than 24 inches above the scaffold support level. • When hook-on and attachable ladders are used on a supported scaffold that is more than 35 feet high, rest platforms must be provided at least every 35 feet. • The minimum rung length for hook-on and attachable ladders is 11-1/2 inches. Rungs must be uniformly spaced with a maximum spacing of 16-3/4 inches between rungs.
Access Requirements Stairway-Type Ladders • Place stairway-type ladders so their bottom rung is not more than 24 inches above the scaffold supporting level. • Rest platforms are required at least every 12 feet. • The step width should be a minimum of 16 inches. Mobile scaffold stairway-type ladders must have a minimum step width of 11-1/2 inches.
Access Requirements Integral Prefabricated Scaffold Access Frames • Rungs on integral prefabricated scaffold access frames must be at least 8 inches long. • Rest platforms must be provided at least every 35 feet on supported scaffolds more than 35 feet high. • Rungs must be spaced no more than 16-3/4 inches apart.
Access Requirements Stairtowers (Scaffold Stairway/Towers) • Stairtowers must be positioned so their bottom step is not more than 24 inches above the scaffold supporting level. • Stairways must be installed between 40 degrees and 60 degrees from the horizontal. Each stairway must be at least 18 inches between stair rails.
Access Requirements Stairtowers (Scaffold Stairway/Towers) • Each side of the scaffold stairway must have a stair rail that includes a toprail and a midrail. Stair rails must be between 28 inches and 37 inches in height, from the top of the stair rail to the surface of the thread. • The toprail of each stair rail system must also serve as a handrail, unless a separate handrail is provided. All handrails must provide a good handhold for employees.
Access Requirements Stairtowers (Scaffold Stairway/Towers) • A landing platform at least 18 inches wide and at least 18 inches long must provided at each level. All treads and landing must have slip-resistant surfaces. Guardrails must be provided on the open sides and ends of each landing.
Access Requirements Ramps and Walkways • All ramps and walkways that are six feet or more above lower levels must have guardrails. • A ramp or walkway that is steeper than one vertical to eight horizontal, must have cleats not more than 14 inches apart that are securely fastened to the flanks to provide footing. Ramps and walkways may not incline more than a slope of one vertical to three horizontal.
Access Requirements Access for Supported Scaffolds • When erecting or dismantling a scaffold, a safe means of access must be provided, if possible. A competent person will determine this based on site conditions and the type of scaffold being erected or dismantled. • Hook-on or attachable ladders must be installed as soon as safe installation and use are possible.
Access Requirements Access for Supported Scaffolds • When erecting or dismantling tubular welded frame scaffolds, end frames with horizontal members that are parallel, level, and not more than 22 inches apart vertically may be used as climbing devices for access.
Fall Protection A competent person will determine if fall protection is feasible during erecting and dismantling procedures. Check with your supervisor or the competent person if you are not sure what type of fall protection is required.
Fall Protection Guardrail Systems • Guardrails must be installed along all open sides and ends of scaffolds that are more than 10 feet above a lower level. • The top edge height of toprails on supported scaffolds manufactured or in service after January 1, 2000 must be installed between 28 and 45 inches above the platform.
Fall Protection Guardrail Systems • The top edge height on supported scaffolds manufactured or in service before that date, and on all suspended scaffolds where both a guardrail and personal fall arrest system are required, must be installed between 36 and 45 inches. • When midrails, screens, mesh, intermediate vertical member, solid panels, or similar structural members are used, they must be installed between the top edge of the guardrail system and the scaffold platform.
Fall Protection Personal Fall Arrest Systems • When engineering controls, such as guardrails and safety nets cannot protect you from fall hazards, then a personal fall arrest system must be used. In the construction industry, a personal fall arrest system is required at heights of 6 feet or more. • A personal fall arrest system must be attached by a lanyard to a vertical lifeline, horizontal lifeline, or scaffold structural member.
Fall Protection Personal Fall Arrest Systems • The personal fall arrest system must limit free fall to six feet or less. • Do not attach the personal fall arrest system to the guardrail system.
Fall Protection Personal Fall Arrest Systems • The anchor point must be able to support 5,000 pounds per attached worker. When vertical lifelines are used, the anchor point must be independent of the scaffold. Standpipes, vents, other piping systems, electrical conduits, outrigger beams, and counterweights are NOT considered safe points of anchorage. • Inspect the personal fall arrest system before each use. Look for wear, tears, cuts, and other signs of damage.
Falling Object Protection A hard hat must be worn whenever there is a possibility of being struck by falling objects, impact while handling material at head level, or other situations where the danger of injuries to the head exists. OSHA (Occupational Safety and Health Administrator) recommends that if a hard hat is needed anywhere on the job site, then you should wear it at all times.