3.6: Conventional Fall Protection Systems

Guardrail Systems

Guardrail systems are barriers erected to prevent workers from falling to lower levels. If the employer chooses to use guardrail systems to protect workers from falls, the following provisions apply:

Image 3:1 Properly Installed Guardrail System (Source: www.osha.gov, Public Domain).

■ Top rails, or equivalent guardrail system members, must be 42 inches plus or minus 3 inches above the walking or working level. When workers are using stilts, the top edge of the top rail, or equivalent member, must be increased to an amount equal to the height of the stilts.
■ Screens, midrails, mesh, intermediate vertical members, or equivalent intermediate structural members must be installed between the top edge of the guardrail system and the walking or working surface when there are no walls or parapet walls at least 21 inches high.
■ When midrails are used, they must be installed at a height midway between the top edge of the guardrail system and the walking or working level.
■ When screens and mesh are used, they must extend from the top rail to the walking or working level and along the entire opening between top rail supports. When necessary, screens and/or mesh must be installed in a manner to prevent a worker from falling underneath.
■ When intermediate members (such as balusters) are used between posts, they must not be more than 19 inches apart.
■ Other structural members (such as additional midrails and architectural panels) must be installed so that there are no openings in the guardrail system more than 19 inches wide.
■ Guardrail systems must be capable of withstanding a force of at least 200 pounds applied within 2 inches of the top edge, in any outward or downward direction, at any point along the top edge.
■ Midrails, screens, mesh, intermediate vertical members, solid panels, and equivalent structural members must be capable of withstanding a force of at least 150 pounds applied in any downward or outward direction at any point along the midrail or other member.
■ Guardrail systems must have a surface to protect workers from punctures or lacerations and to prevent clothing from snagging.
■ The ends of top rails and midrails must not overhang terminal posts, except where an overhang poses no projection hazard.
■ Steel and plastic banding cannot be used as top rails or midrails.
■ Top rails and midrails of guardrail systems must have a nominal diameter or thickness of at least 1/4 inch to prevent cuts and lacerations.
■ If wire rope is used for top rails, it must be flagged at not more than 6-foot intervals with high-visibility material.
■ When guardrail systems are used at hoisting areas, a chain, gate, or removable guardrail section must be placed across the access opening between guardrail sections during those times when hoisting operations are not taking place.
■ When guardrail systems are used at holes, they must be set up on all unprotected sides or edges. When a hole is used for the passage of materials, it must not have more than two sides with removable guardrail sections. When the hole is not in use, it must be covered or provided with a guardrail system along all unprotected sides or edges.
■ If guardrail systems are used around holes being used as access points (such as ladderways), gates must be used. Alternatively, the point of access must be offset to prevent workers from accidentally walking straight into the hole.
■ If guardrails are used on ramps and runways, they must be erected on each unprotected side or edge.
■ Manila, plastic, or synthetic rope used for top rails or midrails must be inspected as frequently as necessary to ensure its strength and stability.

Safety Net Systems

When safety nets are used, they must be installed as close as practicable under the walking or working surface on which workers are working and never more than 30 feet below that level. When nets are used on bridges, the potential fall area from the walking or working surface to the net must be unobstructed. All safety nets must be installed with sufficient clearance underneath to prevent a falling body from hitting the surface or structure below the net. Drop-testing is required to ensure that safety nets and safety net installations are working properly. If an employer can demonstrate that it is unreasonable to perform a drop-test, then the employer or a designated competent person must certify that the net and its installation is in compliance with the standard.

Image 3:2 Safety Nets Used in Construction Sites (Source: www.osha.gov, Public Domain).

■ Do not use defective nets. Inspect nets at least once a week for wear, damage, or deterioration of components such as net connection points.
■ Remove materials, tools, and other items as soon as possible from the net and at least before the next work shift.
■ To work properly, a safety net must have safe openings. Mesh openings must not exceed 36 square inches, and must not be longer than 6 inches on any side. Each opening, measured center-to-center of mesh ropes or webbing, must not exceed 6 inches.
■ All mesh crossings must be secured to prevent the openings from enlarging.
■ Use safety net (or section of net) with a border rope possessing a minimum breaking strength of 5,000 pounds.
■ Do not allow one weak link to compromise a safety net. Use connections between safety net panels that are as strong as integral net components and spaced no more than 6 inches apart.

Personal Fall Arrest System

A personal fall arrest system is a system used to safely stop (arrest) a worker who is falling from a working level. It consists of an anchorage, connectors, and body harness. It also may include a lanyard, deceleration device, lifeline, or suitable combinations of these. When employers choose to use a personal fall arrest system as a means of worker fall protection they must:
■ Limit the maximum arresting force on a worker to 1,800 pounds when used with a body harness.
■ Be rigged so that a worker can neither free fall more than 6 feet nor contact any lower level.
■ Bring a worker to a complete stop and limit the maximum deceleration distance a worker travels to 3.5 feet.
■ Have sufficient strength to withstand twice the potential impact energy of a worker free falling a distance of 6 feet or the free fall distance permitted by the system, whichever is less.
■ Be inspected prior to each use for wear, damage, and other deterioration. Defective components must be removed from service.

Personal Fall Arrest System Components

Snaphooks: Snaphooks must be the locking type and designed and used to prevent disengagement from any component part of the personal fall arrest system. Locking type snaphooks may also be used when designed for the following connections: directly to webbing, rope, or wire rope; to each other; to a Dee-ring to which another snaphook or other connector is attached; to a horizontal lifeline; or to any object which is incompatibly shaped or dimensioned in relation to the snaphook, such that unintentional disengagement could occur by the connected object being able to depress the snaphook keeper and release itself.

Horizontal Lifelines: On suspended scaffolds or similar work platforms with horizontal lifelines that may become vertical lifelines, the devices used to connect to a horizontal lifeline must be capable of locking in both directions on the lifeline. Horizontal lifelines must be designed, installed, and used under the supervision of a qualified person, as part of a complete personal fall arrest system that maintains a safety factor of at least two.

Image 3:3 Know the A, B, Cs of Personal Fall Arrest Systems (Source: www.osha.gov, Public Domain).

Vertical Lifelines and Lanyards: Vertical lifelines and lanyards must have a minimum breaking strength of 5,000 pounds. Lifelines must be protected against being cut or abraded.

Self-retracting Vertical Lifelines and Lanyards: Self-retracting lifelines and lanyards that automatically limit free fall distance to 2 feet or less must be capable of sustaining a minimum tensile load of 3,000 pounds applied to the device with the lifeline or lanyard in the fully extended position. Self-retracting lifelines and lanyards which do not limit free fall distance to 2 feet or less, ripstitch lanyards, and tearing and deforming lanyards must be capable of sustaining a minimum tensile load of 5,000 pounds applied to the device with the lifeline or lanyard in the fully extended position.

Ropes and Straps: Ropes and straps (webbing) used in lanyards, lifelines, and strength components of body belts and body harnesses must be made of synthetic fibers.

Anchorages: Anchorages used to attach personal fall arrest systems must be designed, installed, and used under the supervision of a qualified person, as part of a complete personal fall arrest system which maintains a safety factor of at least two. Alternatively, the anchorages must be independent of any anchorage being used to support or suspend platforms and must be capable of supporting at least 5,000 pounds per worker attached or be capable of supporting at least twice the expected impact load.

Positioning Device Systems

OSHA defines a positioning device system as a body belt or body harness system rigged to allow a worker to be supported on an elevated vertical surface, such as a wall, and work with both hands free while leaning. Body belt or body harness systems are to be set up so that a worker can free fall no farther than 2 feet. Body belts or harnesses must be secured to an anchorage capable of supporting at least twice the potential impact load of a worker’s fall or 3,000 pounds, whichever is greater.

Fall Restraint Systems

OSHA recognizes a fall restraint system as a means of prevention. The system, if properly used, tethers a worker in a manner that will not allow a fall of any distance. This system is comprised of a body belt or body harness, an anchorage, connectors, and other necessary equipment. Other components typically include a lanyard, a lifeline, and other devices. For a restraint system to work, the anchorage must be strong enough to prevent the worker from moving past the point where the system is fully extended, including an appropriate safety factor.

Warning Line Systems

OSHA defines a warning line system as a barrier erected on a roof to warn workers that they are approaching an unprotected roof side or edge, and to designate an area in which roofing work may take place without the use of guardrails, body harnesses, or safety net systems to protect workers in the area. Warning line systems consist of ropes, wires, or chains, plus supporting stanchions. If an employer chooses to use warning line systems, the following provisions apply:

■ The warning line must be erected around all sides of roof work areas.
■ When mechanical equipment is not being used, the warning line must be erected at least 6 feet from the roof edge.
■ When mechanical equipment is being used the warning line must be erected: at least 6 feet from the roof edge parallel to the direction of mechanical equipment operation; and at least 10 feet from the roof edge perpendicular to the direction of mechanical equipment operation.
■ The rope, wire, or chain must be flagged at not more than 6-foot intervals with high-visibility material.
■ The rope, wire, or chain must be rigged and supported so that: the lowest point (including sag) is at least 34 inches from the walking or working surface; and its highest point is no more than 39 inches from the walking or working surface.
■ Stanchions, after being rigged with warning lines, must be capable of resisting, without tipping over, a force of at least 16 pounds applied horizontally against the stanchion, 30 inches above the walking or working surface, perpendicular to the warning line and in the direction of the floor, roof, or platform edge.
■ The rope, wire, or chain must have a minimum tensile strength of 500 pounds.
■ The rope, wire, or chain must be attached to each stanchion in such a way that pulling on one section of the line between stanchions will not result in slack being taken up in the adjacent section before the stanchion tips over.