This training session will provide some basic background information for scaffold installers and users that work in the construction industry. The Occupational Safety and Health Administration, or OSHA, has developed scaffolding standards that set performance-oriented criteria. When followed, they will help protect you from scaffolding hazards such as falls, falling objects, overloading, and electrocution. Note that this session does NOT apply to work platforms or lifts suspended from cranes or derricks. These types of work platforms are covered by OSHA under separate regulations.

Session Objectives

The basic objective of this session is to provide important information about scaffold safety. By the end of this session, you will be able to:

• Understand the nature of scaffold hazards;
• Identify major types of scaffolds and their use;
• Erect, move, operate, inspect, and maintain a scaffold; and
• Implement safe work practices, use fall protection, and protect yourself from falling objects.

Scaffolding Accidents

Scaffolding accidents are a major concern in the construction industry.

• Nine percent of construction-related fatalities each year are related to scaffold use.
• There are almost 10,000 scaffold-related injuries each year in the construction industry.
• A loose plank, or plank slippage, is a common cause of these accidents. Other causes include supports that give way, a worker slipping, or a worker being struck by a falling object.
• A third of the scaffolds involved in injuries did not have a proper guardrail.
• About 25 percent of workers who install and use scaffolds do not have proper safety training, according to OSHA. Such training should include safety requirements for installing work platforms, assembling scaffolds, inspecting scaffolds, and safe practices for working on scaffolds.

Common Hazards of Scaffold Work

Common hazards of scaffold work include the following:

• Electrical contact with scaffolds. Users should stay away from live electrical wires and keep metal objects that conduct electricity away from these wires.
• Slips, trips, and falls—these are the main hazards of scaffolds. Tools and materials can become slip and trip hazards. Faulty guardrails – or no guardrails at all—present obvious falling hazards. Personal fall arrest systems that are inadequate, or not present, can lead to severe injuries or death.
• Falling objects, such as tools and equipment, can cause serious injuries to anyone underneath a scaffold.
• Finally, weather-related hazards, such as rain, ice, and snow, cause slippery surfaces and lead to slips and falls.

Common Types of Scaffolds

This session will present information about the common types of scaffolds used in construction. The most common types include:

• Welded frame scaffolds;
• Mobile, or rolling, scaffolds; and
• Two point suspension, or swing stage, scaffolds.

Less common types of scaffolds, not described in detail here, are:

• Boatswains chairs and floats;
• Tube and coupler scaffolds;
• Interior hung, or needle beam, scaffolds; and
• Ladder staging scaffolds.

Welded Frame and Other Supported Scaffolds

Welded frame and other supported scaffolds must be installed and maintained to meet the following OSHA requirements:

• They must be secured to the building to prevent movement.
• Each tier must be placed with stacking pins or couplings, and locked if uplift can occur.
• Legs on bases must be placed on a firm foundation such as base plates, mud sills, or concrete slabs.
• Each scaffold tier must be cross-braced, and
• Full guardrails are required at the 10-foot level.

Welded Frame and Other Supported Scaffolds (cont.)

Other important requirements for welded frame and other supported scaffolds include:

• Footings must be able to support a loaded scaffold without settlement or displacement. Unstable objects should not be used for support. Construction equipment such as forklifts and front-end loaders cannot be used to support scaffolds.
• The scaffold uprights—including poles and frames—must be plumb and braced to prevent swaying.
• Guys, ties, and braces must be installed to prevent tipping—this means every 20 feet vertically for scaffolds that are 3 feet wide or less, and every 26 feet vertically for scaffolds more than 3 feet wide.
• Finally, supported scaffolds with a height-to-base ratio greater than 4-to-1 must be tied to the structure with guys, ties, and braces to prevent tipping. The guys, ties, and braces should be installed according to the manufacturer’s recommendations.

Mobile (Rolling) Scaffold

Mobile, or rolling, scaffolds must be installed and maintained according to the following OSHA requirements:

• The height of the scaffold must not exceed four times the minimum base dimension. For example, a scaffold that is 3 feet wide cannot be more than 12 feet high. • It must be fully planked, with the platform secured.
• Never ride on a mobile scaffold unless certain specific conditions exist, which are relatively uncommon.
• The scaffold must always be locked in place when in use.

Mobile (Rolling) Scaffolds (cont.)

Additional requirements for mobile, or rolling, scaffolds include:

• The casters must be able to withstand four times the load of the scaffold, with positive locking devices.
• Each tier of the scaffold must be fully braced.
• The platform must have full guardrails if it is 10 feet or more off the ground.
• Power system used to move rolling scaffolds must be designed for that purpose.
• Platforms of rolling scaffolds must not extend beyond the base supports.
• Finally, scaffolds must be leveled using screw jacks or the equivalent.

Two-Point Suspension Scaffold

Two-point suspension scaffolds must meet the following OSHA specifications when installed:

• Inspect the scaffold before installation and during use. Specifically, a competent person must evaluate it and confirm that the supporting surfaces, direct connections, outrigger beams, counterweights, and tiebacks are installed correctly and are capable of supporting the scaffold.
• Roof irons or hooks must be securely installed and anchored.
• Suspension ropes must be able to handle six times the rated load of the scaffold. The ropes may be wire, synthetic, or fabric.
• Finally, the platform must not be more than 36 inches wide, or less than 20 inches wide.

Suspension Scaffolds in General

Here are some general requirements for suspension scaffolds:

• The support device must rest on a surface that can support four times the scaffold load. Support devices include outrigger beams, cornice hooks, parapet clamps, and similar devices.
• The inboard ends of outrigger beams must be bolted or otherwise connected to the to the structure, or the ends must be supported by counterweights. Only items that are specifically intended to be used as counterweights can be used. Do not use construction materials such as bags of sand or cement, roofing felt, or bricks.
• The strength of tiebacks must be equal to the strength of the suspension rope. Tiebacks can be used to secure outrigger beams or other support devices such as cornice hooks, roof hooks, roof irons, and parapet clamps. Tiebacks must be anchored to structurally sound anchor point; this does NOT include pipes, vents, or electrical conduits.
• The platform must be secured to prevent swaying.

Suspension Scaffolds In General (cont.)

Additional requirements for suspension scaffolds include:

• Each suspension rope and connecting hardware must be able to support six times the maximum load of the scaffold.
• Wire ropes used for suspension must be inspected before each work shift for:

– Kinks, bends, and other physical damage, such as flattening;

– Broken wires in the strands; and

– Abrasion, corrosion, or heat damage caused by torches or contact with electrical wires. If there are signs of these kinds of damage, the suspension must be replaced.

• Repaired wire rope cannot be used for suspension.
• Finally, suspension scaffolds must have emergency or automatic braking devices in addition to normal operating brakes. The emergency brake engages automatically when an uncontrolled movement occurs, such as a rapid change in momentum.

Types of Scaffolds – Any Questions?

Now it is time to ask yourself if you understand the information presented so far.

• Do you understand the types of scaffolds used at construction sites and their basic requirements?

It is important for your safety that you understand the types of scaffolds used at our construction sites.

Scaffold Capacity

We will now turn to some of the specific safety requirements of scaffolds, including the design of scaffold components and safe work practices. Scaffold capacity is fundamental to safety.

• Each scaffold and all of its components, including supporting structures, must be designed by a qualified person to carry and support the load for which it is intended.
• The scaffold must be able to support its own weight plus at least four times the maximum intended load. This includes the total weight of all persons, equipment, tools, materials, and any other load that is reasonably expected to be applied to the scaffold and its components at any one time.
• The scaffold must be constructed and loaded according to its design criteria.

Access to Platforms

A specific means of access is required for most platforms.

• Use a ladder or steps, or some other means of access, for platforms that are more than 2 feet above or below a point of access. In other words, it is not permissible to climb up or jump down to a platform that is more than 2 feet above or below you.
• Climbing cross braces is not an acceptable form of access. Doing so creates the potential for tipping the platform, causing damage to the braces, or falling.
• Always use proper forms of access to scaffolds:

– Hook-on ladders can be used as long as they are designed for that type of scaffold. They must be positioned so that they cannot tip over the scaffold.

– Stairways and stair towers must have slip-resistant steps and platforms. They must also have railings and landing platforms at each level.

– Inclined ramps and walkways cannot be sloped more than a ratio of 1 vertical to 3 horizontal. If the slope is steeper than 1 to 8, cleats must be fastened to the plank to provide better footing. Ramps and walkways that are 4 feet or more above a lower level must have guardrail systems.

Platform Construction

Here are some general points about platform construction:

• Working platforms on scaffolds must be fully planked between the front uprights and the guardrail supports. The space between the platform and the uprights, as well as the space between platforms that are next to each other, cannot be more than 1 inch.
• Most platforms, with rare exceptions, must be at least 18 inches wide.
• The front edge of the platform must be no more than 14 inches from the face of the work, unless there are guardrail systems built along the front edge, or you are using a personal fall arrest system.
• The ends of the platforms must extend at least 6 inches over the centerline of the support unless the platform is restrained with hooks or similar methods.
• The cantilevered portion of the platform that hangs over the end supports must be supported or guarded. Either they must be designed to support the load without tipping, or there must be guardrails that prevent anything from being placed on the cantilevered portion. If the end is not supported or guarded, the cantilevered portion cannot exceed 12 inches for a platform that is 10 feet long or less, and cannot exceed 18 inches for a platform that is more than 10 feet long.

Long Platforms

Long platforms have additional safety requirements.

• Generally, abutted platform ends must rest on separate supports.
• However, common supports may be used on platforms that are specifically designed in this way, or that have hooks to provide common support.
• For planks that are overlapped, they must be overlapped over a support. In addition, the overlap must be at least 12 inches or be secured by nailing the planks together or other means.
• If the platform turns a corner, the overlapped plank that is NOT at a right angle to the support must be laid down first, and go UNDER the plank that is at a right angle to the support.

Platform Components

Here are some important points about platform components:

• Wood platforms should not be painted. The idea here is that paint might hide defects in the wood. The platform may be coated with wood preservatives or slip-resistant finishes as long as the covering doesn’t hide the top or bottom wood surfaces. The ends of the platforms may be painted for the purpose of marking or identification.
• The components of one scaffold should not be mixed with components from another manufacturer’s scaffold unless a qualified person determines that the resulting structure is sound.
• Scaffold components should not be modified to make them mix with other types of scaffold systems.
• Finally, components made of dissimilar metals should not be used together. The reason is that dissimilar metals could result in galvanic action that could reduce the strength of the metal components.

Guardrail Systems

Guardrail systems are a highly important part of scaffold safety.

• Guardrails must be installed along all open sides and open ends of scaffolding platforms.
• Guardrails must be in place BEFORE the scaffold is released for use for employees other than those who are actually erecting or dismantling the scaffold.
• The top height of guardrails must be between 38 and 45 inches – 42 inches is the standard height. The top rail may be higher than 45 inches only if there is more than one midrail, and none of the resulting spaces are more than 19 inches.
• The top rails must be capable of withstanding 200 pounds of force, downward or horizontally, at any point. However, top rails of suspension scaffolds are required to withstand only 100 pounds of force.

Guardrail Systems (cont.)

More requirements for guardrails include the following:

• Midrails, when they are used, must be installed between the top rail and the platform, approximately halfway between the two.
• Screens, mesh, and solid panels may be used instead of midrails. They must extend from the top edge of the top rail down to the platform, and along any openings between supports.
• Midrail systems must be able to withstand 150 pounds of horizontal or downward force. However, midrails on suspension scaffolds need only withstand 75 pounds of force.
• Cross braces may be used instead of top rails or midrails provided that they do not allow openings of more than 19 inches at any point.
• Finally, guardrails must not present a puncture or laceration hazard. They should be free of burrs or snags that could catch an employee’s clothing. The ends of rails should not overhang the end posts unless you’re sure there is no projection hazard.

Projection from Falling Objects

Protection from falling objects such as hand tools and debris is another essential part of scaffold systems.

• Always wear a hard hat when working on or under a scaffold.
• Use toeboards on scaffolds. Toeboards must be installed on open edges to prevent objects from being kicked off platforms and onto workers below. Toeboards must be at least 3½ inches high.
• Use screen or panels on scaffolds when items are stacked higher than the toeboard. Remember that the panels or screens need to extend all the way from the top rail to the platform.
• Canopies, debris nets, or catch platforms may be used to protect workers from falling objects, so long as they are strong enough to withstand the impact of falling objects.
• Barricade the areas below the scaffold if toeboards or screens are not sufficient to prevent the hazard of falling objects. No one is allowed to enter a barricaded area.

Scaffold Safe Practices

Safe practices for scaffolds include a number of common sense rules presented here and on the next slide.

• Scaffolds must be erected, dismantled, and altered only under the supervision of a competent person who is qualified for these tasks. The competent person must select experienced and trained employees for these jobs.
• Inspect scaffolds before each work shift, or after any occurrence that might affect the integrity of the structure. Only a person who is qualified to do so may conduct the inspection.
• Replace or repair any damaged or weakened scaffold components immediately. The scaffold should be removed from service until the component is repaired or replaced.
• Keep scaffolds away from energized power lines. Conductive material on scaffolds, such as metal, presents a serious hazard. The scaffold must be at least 3 feet from a power line of less than 300 volts, and at least 10 feet away from a power line of greater than 300 volts.

Scaffold Safe Practices (cont.)

• Do not load scaffolds beyond their rated capacities, or beyond their maximum intended loads.
• Do not move scaffolds horizontally while you or others are on them, unless a professional engineer has designed them for such movement or they are considered to be mobile scaffolds that are intended to be used in this way.
• Do not work on scaffolds that are covered with snow and ice, or other slippery materials, unless the purpose is to remove the slippery materials.
• Do not work on scaffolds during storms or high winds unless a competent person has determined that it is safe to do so, and you are protected with a personal fall arrest system or a wind screen. Wind screens can be used only if the scaffold is secured against the expected wind forces.
• Finally, debris should not be allowed to accumulate on platforms. Leaves, paper, materials, and tools can become a slip or trip hazard.

Ladders on Scaffolds

Ladders on scaffolds are generally not permitted except under certain circumstances.

• Ladders are prohibited entirely except on large area scaffolds that meet certain strict criteria.
• Ladders must be secured against sideways movement if they are placed against another structure, such as a building wall.
• Platforms for ladders must be secured to the scaffolding to prevent the platforms from moving. If possible, the ladder legs should be placed on one plank to prevent the ladder from destabilizing.
• The ladder legs must be secured to the platform to prevent it from slipping off.
• You are not permitted to stand on boxes, barrels, stacks of materials, or other items to increase working height when you are on a scaffold.

Fall Protection

Fall protection of various kinds is usually needed with scaffold systems.

• It is required whenever the work is occurring 10 feet or more above a lower level. Lower levels include the ground, floors, roofs, pits, tanks, materials, or equipment.
• Use approved personal fall arrest systems when required for certain types of scaffolds, such as boatswain chairs, catenary scaffolds, needle beam scaffolds, and ladder jack scaffolds.
• Guardrail systems are required for walkways that are included as part of a scaffolding system, as well as for open sides and open ends of platforms.
• Suspension scaffolds require both guardrails AND personal fall arrest systems.

Personal Fall Arrest System

Personal fall arrest systems can save your life, and are required in scaffold work under certain conditions. Remember these requirements for personal fall arrest systems:

• Vertical lifelines, when used, must be fixed to an anchor point that is independent of the scaffold. The lifeline must be protected from sharp edges and possible abrasion. Anchor points can be structural components of buildings, but not piping, vents, outrigger beams, or counterweights.
• Vertical lifelines must not be anchored to the same point as the suspension ropes of the scaffold, or to the scaffold suspension ropes or support lines themselves.
• Horizontal lifelines, when used, must be anchored to two or more structural members of the scaffold. When used on a suspension scaffold, the lifeline may also be attached both to the suspension lines above the hoist and the brake attached to the end of the scaffold. However, horizontal lifelines may not be attached only to the suspension ropes.
• Suspension scaffolds must be equipped with additional support lines and automatic brakes if lanyards are connected to the structural members. The purpose of this requirement is to maintain the ability to stop a fall even if one of the suspension ropes fails.
• As a final point, anchor points and lifelines must be capable of supporting at least 5,000 pounds of force.

Any Questions?

Now it is time to ask yourself if you understand the material presented.

• Do you understand the safety specifications required for scaffolds or about safe work practices on scaffold?

It is important for your safety that you understand the safety specifications of scaffolds and safe work practices while working on scaffolds.

Key Points to Remember

Key points to remember from this training session on scaffolds include the following:

• Inspect the scaffold before each work shift; remember that you must be qualified to perform this inspection.
• Properly secure all platforms on a scaffold.
• Do not overload scaffolds beyond their rated capacity or their intended load.
• Wear a personal fall arrest system whenever it is required, or simply to increase the degree of safety.
• Finally, make sure you understand scaffold hazards and always follow accident prevention measures.

This concludes the training session on scaffolds in construction.