Fall Protection Systems for Residential Construction
July 24, 2015
Fall protection in the construction industry remains a serious issue. In fact, 36.5 percent of all occupational fatalities in the construction industry were due to falls from height in 2013. For this reason, fall protection systems in the construction industry are extremely important for worker safety. In the residential construction industry, fall protection systems are a unique challenge because forces of a fall event cause wood structures to deflect. This deflection causes many to believe the misconception that proper use of fall protection systems requires modifying and reinforcing wood structures before use.
For a project to be considered “residential construction,” OSHA says that “the end-use of the structure being built must be as a home,” and “the structure being built must be constructed using traditional wood frame construction materials and methods.” Wood structures make providing anchorage for residential construction fall protection systems difficult. Anchorage is needed near the peak at the ridge vent location. OSHA states, “Anchorages to which personal fall arrest equipment is attached shall be capable of supporting at least 5,000 pounds (22.2 kN) per employee attached, or shall be designed, installed, and used as part of a complete personal fall arrest system which maintains a safety factor of at least two, under the supervision of a qualified person.” This safety factor of at least two is extremely important to understand in residential construction because finding an anchorage point that can support 5,000 pounds is challenging, if not impossible, to achieve on a residential construction jobsite.
The safety factor of at least two means that a 900-pound rated SRL needs an anchorage point that can support at least 1,800 pounds. According to Daniel Hindman’s research, trusses with sway bracing reach or surpass the required 1,800 pounds and can carry the load of a fall event. Hindman said that sway bracing of two 2×6’s added 1,000 pounds to the maximum average arresting force (MAAF) of the carried load. Also, there are two important factors to follow when using trusses as an anchorage point. First, the load on the trusses can never be perpendicular. Second, if the anchor point is at foot level, a leading-edge self-retracting lanyard (SRL-LE) rated for anchorage at foot level must be used. Regular SRLs are not tested for that type of freefall and could fail during a fall event. It is important to note that although trusses can withstand the forces of a fall, they do deflect during a fall event and must be inspected and replaced or repaired. Hindman noted the typical damage that occurred to trusses during testing: rotation of truss plates, rotation of the truss-heel connection, withdrawal of bracing nails, and splitting of truss chords. When using trusses with sway bracing as anchorage points, make sure to understand Hindman’s testing results. He states exactly how he constructed his trusses and concludes that trusses with sway braces can withstand the forces of a fall event. For more information, visit Structural Efficacy of Residential Structures for Fall Protection Systems. As always, if you have any questions, we are here to help.
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