Modified "walk-through" ladder tested in virtual reality laboratory
(Images from the NIOSH Virtual Reality Laboratory showing a subject moving to a sloped roof from a walk-through ladder, left, and from a regular ladder, right. Photos from NIOSH.)
This month is National Ladder Safety Month, but ladder safety is a year-round priority at the National Institute for Occupational Safety and Health (NIOSH) where scientists study how to prevent ladder-related falls. In a new study published in the journal Applied Ergonomics, a “walk-through” ladder was comparable in safety to regular ladders tested in NIOSH Virtual Reality Laboratory in Morgantown, West Virginia.
If used improperly, ladders in the workplace can increase the risk of fall-related injuries and deaths. In 2010, 132 workers died in work-related falls from ladders, according to the Bureau of Labor Statistics. Most of these deaths occurred in construction. Walking from a ladder to a rooftop, or vice versa, at elevated heights can increase the risk of falling. To provide workers with something to grasp, walk-through ladders have extended handles on their tops, usually provided as ladder accessories. Although these ladder accessories are commercially available, the safety of walk-through ladders compared to regular ladders was unclear.
In this study, NIOSH scientists compared walk-through to regular extension ladders in the NIOSH Virtual Reality Laboratory, which uses computerized, surround-screen technology to mimic the experience of being at an elevated height. While study participants walked from the ladders to a simulated rooftop and back, the scientists measured participants’ body movements and the amount of force on the ladders and estimated the required friction at the ladder base. Both types of ladders had comparable measurements that indicated a low risk of sliding out and causing a fall when positioned at the proper 75.5-degree angle. While the walk-through ladder made it easier for participants to move from the ladder to the simulated roof, it did not ease the transition back to the ladder. Study participants included 16 experienced and 16 inexperienced male ladder users. The average age of the experienced group was 40 years, and the average age of the inexperienced group was 33 years.
For ladder safety, the scientists recommend placing ladders at the proper angle and tying them to a secure structure at the top and, if possible, the base. To help workers and other user’s position extension ladders correctly, NIOSH developed the award-winning Ladder Safety app. This app is available for free download from the Apple Store and Google Play.
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