ABSTRACT Accidents involving portable ladders are a common cause of serious occupational and non-occupational injuries throughout the industrialized world. Many of these injuries could be prevented with proper education, training and usage of portable ladders. This research focused on the human factors and engineering aspects of portable extension ladder usage. Results and analysis revealed evidence of unsafe acts that could lead to catastrophic ladder slide-out accidents in real-life situations. Six ladder setup methods were evaluated based on placement angles: the Basic, 75 Degree, Stand-Reach, L Sticker, 4:1, and Level methods. The level method produced the most accurate results with the lowest variability. Setup methods varied in complexity and level of instruction. Additional investigation included determining the coefficient of friction of common ladder setup surfaces in clean and contaminated conditions. Based on known ladder setup angles and coefficients of friction, a detailed engineering analysis was performed to determine the total number of slide-out failures for each ladder setup method. Analysis of the overall results revealed the need for additional user training and education. Based on test subjects\u27 setup angles, the ladder slide-out failure rate would have been 12.2 percent for ladders set up on a surface with the lowest measured coefficient of friction. When broken down by ladder setup method, the 4:1 Method had a failure rate of 18.8 percent, the 75 Degree Method had a failure rate of 15.2 percent, and the Basic Method had a failure rate of 9.8 percent. Overall results have been considered for modifications of existing ladder standards as well as areas of additional research
