Research to improve extension ladder angular positioning

Abstract

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. The objective of the study was to comparatively evaluate the effectiveness of a multimodal angle indicator with other existing methods for extension ladder angular positioning.Twenty experienced and 20 inexperienced ladder users participated in the study. Four ladder positioning methods were tested in a controlled laboratory environment with 4.88 m (16 ft) and 7.32 m (24 ft) ladders in extended and retracted positions. The positioning methods included a noinstruction method, the current standard anthropometric method, and two instrumental methodsa bubble level indicator, and a multimodal indicator providing direct feedback with visual and sound signals. Performance measures included positioning angle and time.The results indicated that the anthropometric method was effective in improving the extension ladder positioning angle (p < 0.001); however, it was associated with considerable variability and required 50% more time than no-instruction. The bubble level indicator was an accurate positioning method (with very low variability), but required more than double the time of the noinstruction method (p < 0.001). The multimodal indicator improved the ladder angle setting as compared to the no-instruction and anthropometry methods (p < 0.001) and required the least time for ladder positioning among the tested methods (p < 0.001).An indicator with direct multimodal feedback is a viable approach for quick and accurate ladder positioning. The main advantage of the new multimodal method is that it provides continuous feedback on the angle of the device and hence does not require repositioning of the ladder. Furthermore, this indicator can be a valuable tool for training ladder users to correctly apply the current ANSI A14 standard anthropometric method in ladder angular positioning.The multimodal indicator concept has been further developed to become a hand-held tool in the form of a smart phone application. *Corresponding author. Tel.: +1 304 285 6268; fax: +1 304 285 6047. psimeonov@cdc.gov (P. Simeonov).

Fall Prevention Research and Practice: A Total Worker Safety Approach

“…NIOSH also identified factors affecting extension ladder angular positioning30 ) . Ladder users tended to position an extension ladder at a shallower angle than the angle recommended by the current ladder safety standard.…”

“…An innovative inclination indicator developed by NIOSH researchers has been tested to improve the accuracy and reduce the time for ladder positioning. This concept of an inclination indicator with visual, sound, and vibrating functions, has been further developed to become a ladder safety software application (app) for mobile devices which features a multimodal indicator and a graphic-oriented guide for ladder selection, inspection, positioning, accessorizing, and safe use31 ) (Fig. 3

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Straight ladder inclined angle in a field environment: the relationship among actual angle, method of set-up and knowledge

“…The ANSI-recommended stand and reach has been widely evaluated. The angle set-up results associated with this method are 70.55° ± 4.85° by Young and Wogalter ( 2000 ), 74.1° ± 3.2° by Knox and Van Bree ( 2010 ), 76.2° ± 3.64° by Campbell and Pagano ( 2014 ), and an average of 73.5° by Simeonov et al ( 2013 ). Several other methods have been proposed for setting up portable straight ladders at the proper angle.…”

“…Methods based on instruments also have been widely evaluated and results, in general, were closer to the recommended 75.5° angle and highly consistent across participants, with small variations. For the bubble method, Young and Wogalter ( 2000 ) and Campbell and Pagano ( 2014 ) reported 75.66° ± 0.26° and 75.2° ± 0.34°, respectively, while Simeonov et al ( 2013 ) reported an average angle of 75.8°. The multimodal indicator method evaluated by Simeonov et al ( 2013 ), in which a ladder accessory provides visual and auditory signals as a direct feedback indication of proximity to the recommended ladder angle, resulted in an average angle of 75.4°.…”

“…For the bubble method, Young and Wogalter ( 2000 ) and Campbell and Pagano ( 2014 ) reported 75.66° ± 0.26° and 75.2° ± 0.34°, respectively, while Simeonov et al ( 2013 ) reported an average angle of 75.8°. The multimodal indicator method evaluated by Simeonov et al ( 2013 ), in which a ladder accessory provides visual and auditory signals as a direct feedback indication of proximity to the recommended ladder angle, resulted in an average angle of 75.4°. In addition, a fireman method was evaluated, similar to the standard stand and reach method, in which the participants extended both arms horizontally and held the side rails with both hands, rather than the closest rung (Simeonov et al 2012 ).…”