Human Factors Researchers Suggest New Sizing System for Fall Protection Equipment

Santa Monica, CA, June 4, 2007 ' Falls are the leading cause of fatalities in the construction industry; OSHA estimates an average of 362 fatal falls per year. Fall arrest harnesses provide the last line of defense for more than 5 million workers at construction sites where falls cannot be prevented. But according to the results of a study just published in Human Factors: The Journal of the Human Factors and Ergonomics Society, current fall arrest harnesses did not properly fit at least 24% of the men and 31% of the women in the study.



Current sizing for commercial harnesses is derived from 1970s'1980s anthropometric (human body) measurements of members of the military services. These data do not represent today's civilian worker population, which has become more diverse and now includes more women. The result is greater variation in workers' range of body dimensions and shapes.

The authors of this study ' human factors/ergonomics researchers from the National Institute for Occupational Health and Safety (NIOSH), Total Contact, Inc., and the University of Michigan ' obtained anthropometric data from 216 white, Hispanic, African-American, and multiracial men and women age 18 to 56 who had selected harnesses they felt fit them the best. (This group is fairly representative of the worker population in the United States.) These participants were then scanned with a 3-D full-body scanner, first while standing and then while being suspended by the harness.

After integrating criteria established for the harness manufacturing industry with the body measurement data from the study participants, the researchers created a comprehensive test for assessing the overall fit of the harnesses. They then derived eight models, which provided unique 3-D anthropometric information for better defining harness size groups. "This grouping will help harness designers to restructure current harness sizing plans . . . to accommodate at least 96% of the population," they concluded.

The researchers' alternative fitting system would replace the existing four unisex size options with two sizes for women and three for men. They believe that adoption of this new system by harness manufacturers can help the construction industry reduce the risk of injuries and fatalities from improper size selection and fit. To date, two fall arrest harness manufacturers have worked with NIOSH to transfer the research results into design practice.

Download the full article, 'Evaluation of Fall Arrest Harness Sizing Schemes,' by Hongwei Hsiao et al. (Volume 49, Number 3, June 2007). For more information, contact HFES Communications Director Lois Smith (310/394-1811).

The Human Factors and Ergonomics Society, which celebrates its 50th anniversary in September 2007, is a multidisciplinary professional association of more than 4,700 persons in the United States and throughout the world. Its members include psychologists and other scientists, designers, and engineers, all of whom have a common interest in designing systems and equipment to be safe and effective for the people who operate and maintain them.

-Forwarded by Todd Teets