Firefighting is an occupation with a high musculoskeletal injury rate. In 2016, the Bureau of Labor Statistics (BLS) data indicated that fire fighters reported a musculoskeletal disorder (MSD) rate of 179 per 10,000 full-time workers (more than five times the national average); with a total of 5,760 MSD. The statistics showed that approximately 40% of firefighters’ injuries occurred on the fire ground, 21% account for slips, trips, and falls. Firefighter balance on the fire ground is affected by their fire-protective clothing ensemble which include a very crucial self-contained breathing apparatus (SCBA) that provides an external air supply. Therefore, it is necessary to conduct research to determine the appropriate weight limit to reduce the rate of MSD of firefighters. The objectives of this study were to model body reactions to SCBA weight and determine appropriate weight limits for different firefighting tasks using the 3 Dimension Static Strength Prediction Program (3DSSPP). Firefighter tasks were summarized and classified as eight representative postures to perform the simulation. The postures are stair climb, hose advance, overhaul, hammer slam, hose carry, weighted carry, dummy drag, and rope pull. All eight postures were manually modelled in 3DSSPP. The forces exerted on the body by the SCBA unit weight were calculated separately based on the biomechanical model (abdominal bending, lateral bending and torso rotation). 3DSSPP calculated low back (L4/L5) compression forces, strength percent capabilities of ankle, knee, hip, torso, shoulder, elbow, and wrist and compared data to NIOSH guidelines. The maximum SCBA weights were calculated for each posture ranging from 30 to 64 lbs, and the maximum comfortable weight limit being 39 lb. The results of the simulation analysis can be useful to researchers in assessing risks, developing worker training, selecting appropriate personal protective equipment, and recommending ergonomic interventions to mitigate risks.
Dr. Xu is a General Engineer/ Associate Service Fellow for human factor and ergonomics research at NIOSH NPPTL. She has a Ph.D. degree in mechanical engineering and a graduate level of statistics. She has been working in mechanical engineering and public health research area over 15 years at university, industry and government as a research mechanical engineer and authored or coauthored 18 publications. Her research areas are biomechanical engineering, occupational safety for prevention of work-related illness and injury, and respirator research for SCBA, SCSR and PAPR etc.