Improved human-tractor interface designs, such as well-accommodated operator enclosures (i.e. cabs and protection frames) can enhance operator productivity, comfort and safety. This study investigated farm-worker anthropometry and determined the critical anthropometric measures and 3-D feature envelopes of body landmarks for the design of tractor operator enclosures. One hundred agriculture workers participated in the study. Their body size and shape information was registered, using a 3-D full-body laser scanner. Knee height (sitting) and another eight parameters were found to affect the cab-enclosure accommodation rating and multiple anthropometric dimensions interactively affected the steering wheel and gear-handle impediment. A principal component analysis has identified 15 representative human body models for digitally assessing tractor-cab accommodation. A set of centroid coordinates of 34 body landmarks and the 95% confidence semi-axis-length for each landmark location were developed to guide tractor designers in their placement of tractor control components in order to best accommodate the user population. Finally, the vertical clearance (90 cm) for agriculture tractor enclosure in the current SAE International J2194 standard appeared to be too short as compared to the 99th percentile sitting height of male farm workers in this study (100.6 cm) and in the 1994 National Health and Nutrition Examination Survey III database (99.9 cm) and of the male civilian population in the 2002 Civilian American and European Surface Anthropometric Resource database (100.4 cm).

Objective This article reports new anthropometric information of U.S. firefighters for fire apparatus design applications (Study 1) and presents a data method to assist in firefighter anthropometric data usage for research-to-practice propositions (Study 2). Background Up-to-date anthropometric information of the U.S. firefighter population is needed for updating ergonomic and safety specifications for fire apparatus. Method A stratified sampling plan of three-age by three-race/ethnicity combinations was used to collect anthropometric data of 863 male and 88 female firefighters across the U.S. regions; 71 anthropometric dimensions were measured (Study 1). Differences among original, weighted, and normality transformed data from Study 1 were compared to allowable observer errors (Study 2). Results On average, male firefighters were 9.8 kg heavier and female firefighters were 29 mm taller than their counterparts in the general U.S. population. They also have larger upper-body builds than those of the general U.S. population. The data in weighted, unweighted, and normality transformed modes were compatible among each other with a few exceptions. Conclusion The data obtained in this study provide the first available U.S. national firefighter anthropometric information for fire apparatus designs. The data represent the demographic characteristics of the current firefighter population and, except for a few dimensions, can be directly employed into fire apparatus design applications without major weighting or nonnormality concerns. Application The up-to-date firefighter anthropometric data and data method will benefit the design of future fire apparatus and protective equipment, such as seats, body restraints, cabs, gloves, and bunker gear.

Workers wearing full-body safety harnesses are at risk for suspension trauma if they are not rescued in 5 to 30 min after a successfully arrested fall. Suspension trauma, which may be fatal, occurs when a person's legs are immobile in a vertical posture, leading to the pooling of blood in the legs, pelvis, and abdomen, and the reduction of return blood flow to the heart and brain. To measure suspension tolerance time, 22 men and 18 women with construction experience were suspended from the chest D-ring (CHEST) and back D-ring (BACK) of full-body, fall-arrest harnesses. Fifteen men and 13 women from the original group of subjects were then suspended using a newly developed National Institute for Occupational Safety and Health harness accessory (ACCESS), which supports the upper legs. Midthigh circumference changes were 1.4 and 1.9 cm, changes in minute ventilation were 1.2 and 1.5 L/min, changes in heart rate (HR) were 15.1 and 21.6 bpm, and changes in mean arterial pressure were 5.1 and -2.6 mmHg (p < or = 0.05) for all subjects during CHEST and BACK, respectively. Kaplan-Meier median suspension time for all subjects for the CHEST condition was 29 min (range 4-60 min) and 31 min (range 5-56 min) for the BACK condition. The 95th percentile for suspension time was 7 min for CHEST and 11 min for BACK. Cox regression revealed that body weight had a statistically significant effect on the time until experiencing a medical end point (p < or = 0.05) during the BACK condition. Mean (+/- SD) suspension time was 58 +/- 6 min (range 39-60 min) for all subjects for the ACCESS condition. There were no terminations due to medical symptoms during the ACCESS suspension, changes in physiological variables were small, and 85% of ACCESS subjects completed 60-min suspensions. These data provide information on motionless suspension tolerance time to standards-setting organizations and demonstrate the potential of a prototype harness accessory to delay or prevent suspension trauma.

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.