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Factors Affecting Extension Ladder Angular Positioning
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Jun 2012
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Source: Hum Factors. 54(3):334-345.
[PDF-4.06 MB]
Details:
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Alternative Title:Hum Factors
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Description:Objective
The study objectives were to identify factors affecting extension ladders’ angular positioning and evaluate the effectiveness of two anthropometric positioning methods.
Background
A leading cause for extension ladder fall incidents is a slide-out event, usually related to suboptimal ladder inclination. An improved ladder positioning method or procedure could reduce the risk of ladder stability failure and the related fall injury.
Method
Participants in the study were 20 experienced and 20 inexperienced ladder users. A series of ladder positioning tests was performed in a laboratory environment with 4.88-m (16-ft) and 7.32-m (24-ft) ladders in extended and retracted positions. The setup methods included a no-instruction condition and two anthropometric approaches: the American National Standards Institute A14 and “fireman” methods. Performance measures included positioning angle and time.
Results
The results indicated that ladder setup method and ladder effective length, defined by size and extended state, affected ladder positioning angle. On average, both anthropometric methods were effective in improving extension ladder positioning; however, they required 50% more time than did the no-instruction condition and had a 9.5% probability of setting the ladder at a less-than-70° angle. Shorter ladders were consistently positioned at shallower angles.
Conclusion
Anthropometric methods may lead to safer ladder positioning than does no instruction when accurately and correctly performed. Workers tended to underperform as compared with their theoretical anthropometric estimates. Specific training or use of an assistive device may be needed to improve ladder users’ performance.
Application
The results provide practical insights for employers and workers to correctly set up extension ladders.
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Pubmed ID:22768637
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Pubmed Central ID:PMC4679184
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