Objective: This study investigated the effect of body size and shape and harness fit on suspension tolerance time.
Background: Fall victims may develop suspension trauma, a potentially fatal reduction of return blood flow from legs to the heart and brain, after a successfully arrested fall if they are not rescued quickly or the harness does not fit them well.
Method: For this study, 20 men and 17 women with construction experience were suspended from the dorsal D-ring of a full-body fall-arrest harness. Their suspension tolerance time, physical characteristics, and harness fit levels were assessed.
Results: Body characteristics (i.e., weight, stature, upper- and lower-torso depths) were associated with decreased suspension tolerance time (r = –.36 ~ –.45, p ≤ .03). In addition, harness fit affected suspension tolerance time; workers with a torso angle of suspension greater than 35°, a thigh strap angle greater than 50°, or a poorly fitting harness size had shorter suspension tolerance time (mean differences = 14, 11, and 9.8 min, respectively, p ≤ .05).
Conclusion: Body size and harness fit were predictors of suspension tolerance time. Selecting well-fit harnesses and establishing a 9-min rescue plan are suggested to ensure that no more than 5% of workers would experience suspension trauma.
Applications: The study provides a basis for harness designers, standards writers, and manufacturers to improve harness configurations and testing requirements for better worker protection against suspension trauma.
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