Design of testing apparatus to evaluate the strength of guardrail systems.
McKenzie-EA Jr.; Bobick-TG; Cantis-DM
Proceedings of the ASME 2004 International Mechanical Engineering Congress and Exposition (IMECE2004), November 13-19, 2004, Anaheim, California. New York: American Society of Mechanical Engineers, IMECE2004-59575, 2004 Nov; :137-142
Fall-related occupational injuries and fatalities are serious problems in the U.S. construction industry. An important sub-set of falls-to-lower-level incidents is when workers fall through openings or surfaces, including skylights. OSHA regulations require that holes (openings) in roofs must be protected by a guardrail or cover, or nearby workers must use personal fall-arrest systems. The National Institute for Occupational Safety and Health (NIOSH), Division of Safety Research, Morgantown, WV has initiated a pilot project to evaluate the effectiveness of guardrail systems. Two commercially available edge-protection products were evaluated as guardrails around a roof opening. Installation methods for the two edge-protection products, which have not been designed to be used as guardrails for openings, are compared to job-built guardrails constructed of two-by-four lumber. To evaluate how well the commercial products comply with existing OSHA regulations as a guardrail, an experimental hypothesis and a laboratory-based testing system were developed. OSHA regulations require that a force of at least 200 pounds shall be supported by the top rail of the guardrail system. The governing variable is the 200-pound force. This was generated by using a weighted rescue dummy mounted on a specially designed hinged steel frame. Adjusting the fall distance of the dummy, a dynamic 200-pound force was generated in the middle of the top rail. To evaluate the overall strength of the guardrail systems, a hydraulic testing apparatus was designed. Combining a hydraulic cylinder and pump, with a piezoelectric force transducer, a pull-to-failure (PTF) test apparatus was developed. This system was designed to pull the guardrail systems in the same direction in which the test dummy fell. Maximum PTF forces were recorded for both commercially available products and then compared with the job-built systems.
Occupational-hazards; Injuries; Construction-industry; Construction-workers; Roofing-industry; Roofers; Laboratory-testing; Safety-research
Proceedings of the ASME 2004 International Mechanical Engineering Congress and Exposition (IMECE2004), November 13-19, 2004, Anaheim, California