Masonry Magazine August 1998 Page. 26
Guardrail systems must be able to withstand 150 pounds of pressure. If 100 pounds, it must withstand 75 pounds. Screens, mesh, or other structural members must be installed between the top edge of the guardrail system and the walking/working surface when there is no wall or parapet wall at least 21 inches high. These structures must withstand 150 pounds of pressure. Make sure that the guardrails do not pose additional hazards. Guardrail system surfaces must be smooth to prevent punctures or lacerations, and snagging of clothing. Edges or connections must not extend into the work area and cause a projection hazard. Steel banding and plastic banding cannot be used for top rails or midrails. If wire rope is used for top rails, place flags every 6-feet.
Wood, pipe or structural steel can be used for guardrail systems. If wood is used, the specifications listed should be followed. Wood components shall be minimum 1500 lb-ft/in(2) fiber (stress grade) construction grade lumber; the posts shall be at least 2-inch by 4-inch lumber spaced not more than 8 feet apart on centers; the top rail shall be at least 2-inch by 4-inch lumber, the intermediate rail shall be at least 1-inch by 6-inch lumber. All lumber dimensions are nominal sizes.
If pipe is used, these specifications should be followed. Posts, top rails, and intermediate railings shall be at least one and one-half inches nominal diameter (schedule 40 pipe) with posts spaced not more than 8 feet apart on centers.
If structural steel railings are used, these specifications should be followed. Posts, top rails and intermediate rails shall be at least 2-inch by 2-inch by 3/8-inch angles, with posts spaced not more than 8 feet apart on centers.
Personal Fall Arrest Systems
A personal fall arrest system is a piece of equipment that has become synonymous with fall protection. Its use is common to all elevated surfaces, rooftops and scaffolds alike. Since the release of the Subpart M Fall Protection its requirements have been referenced by other standards for equipment specifications. These requirements are referenced here for general use.
A Personal Fall Arrest System is used to stop an employee from falling more than 6 feet. It consists of an anchorage, connectors, a body harness and may include a lanyard, deceleration device, lifeline, or combinations of these. (As of January 1, 1998, the use of a body belt for fall arrest was prohibited.) Body harnesses distribute the forces of a fall over at least the thighs, pelvis, waist, chest and shoulders. The lanyard, a flexible line of rope, wire rope, or strap, allows connection of a body harness to a deceleration device, lifeline, or anchorage. There are two types of lifelines. A vertical lifeline consists of a flexible line for connection to an anchorage at one end to hang vertically. Each employee must have a separate vertical lifeline. A horizontal lifeline connects to anchorages at both ends. It stretches horizontally and serves as an anchorage for other parts of the system.
Personal Fall Arrest Systems must be capable of withstanding the force of a potential fall. The system is tested with a 220 pound weight. The maximum arresting force cannot exceed 2,520 pounds. Lanyards and vertical lifelines must have a minimum breaking strength of 5,000 pounds. Anchorages used for attachment of personal fall arrest equipment must be capable of supporting at least 5,000 pounds per employee attached.
Fortunately, when dealing with a personal fall arrest system except for the anchorage point, the equipment is a manufactured item. Consult with your vendor. They can provide additional information on various styles and features. Consider retractable lifelines. Depending upon the operations you perform, these devices can reduce hazard. For example, they eliminate slack in lines and reduce the entanglement hazard. Some systems are available with self rescue. If an employee falls, a self-contained kit on the system allows them to release the original line and lower themselves with a secondary line.
Conclusion
Regardless of the equipment chosen, the responsibility for safety belongs to everyone. Make sure employees are aware of the necessary equipment specifications. Ensure vendors provide OSHA compliant material. Question quality in relation to the requirements. If guardrail systems are erected by other trades or come as part of a rental package, confirm that the provider has followed the appropriate specifications. Finally, place a competent person in charge of all activities.