Mast climbing work platforms, also known as mast climbers, are becoming more and more common on U.S. construction sites. Mast climbers have a power-driven work platform that climbs a vertical tower, allowing them to reach much higher and carry greater loads than traditional scaffolds. Although they were available in the U.S. in the 1980s, they became more common in the early 1990s when contractors began using them as an alternative to traditional tube-and-coupler scaffolds. On average, about 16,800 people now work on some 5,600 mast climbers each day. Workers spend an additional 3.3 million work hours erecting and dismantling mast climbers each year (O'Shea, personal communication, 7/20/10). Mast climbers offer many advantages over other forms of scaffolding. They are quicker to erect and dismantle, and they are potentially much better at reducing the risk of shoulder and lower back injuries to workers, since they can be adjusted to an optimum working height. Yet some of their advantages, such as their ability to reach hundreds of feet in the air, can create new and potentially hazardous conditions. When installed and used correctly, they are as safe as other scaffold types, but when they fail, the results are usually catastrophic, often involving multiple deaths and serious injuries. For instance, the 12 mast climber incidents described in this report cost 18 lives and a number of serious injuries. Yet the true rate of deaths and serious injuries due to mast climber collapses is not known. OSHA regulations treat mast climbers under the general category of scaffolds, and work site incident reports often do not specify the type of scaffolds involved in fatalities. In 2006, CPWR - The Center for Construction Research and Training established a work group of representatives from industry, government, and labor to examine problems and discuss solutions to improve the safety of this important new equipment available to contractors. The group's main goal was to develop recommendations that could be used by regulators and those responsible for specifying and contracting work that involves mast climbers. This paper presents a compilation of the work group's recommendations, which are broken into five sections: 1) Institute new training programs and qualifications for training providers, including awareness training for anyone using, working on, or operating mast climbers (the appendix contains a detailed outline for awareness training), an erector/dismantler course, and siteand model-specific training, as well as clear instructor qualifications; 2) Adopt engineering and administrative controls that address involvement of persons qualified in structural engineering where needed, as well as shoring, anchorage systems, load tables, enclosures, wind, inspections, maintenance, vertical climbs, and fall protection; 3) Define roles and responsibilities of manufacturers, suppliers, distributors, users, and site owners; 4) Determine specific qualifications and roles of all participants to improve site safety and oversight; and 5) Update OSHA standards and consensus standards to address the unique design and safe use of mast climbers.
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