Ergonomic interventions for the reduction of low back stress in framing carpenters in the home building industry

Abstract Framing carpenters in the residential sector of the construction industry have exposure to many of the documented risk factors for low back disorders. On-site exposure data were collected from a sample of residential framing carpentry subcontractors and these were summarized using the continuous assessment of back stress (CABS) methodology. From these analyses those tasks placing the greatest stress on the low back were identified and prototype interventions were developed that reduced exposures to the specific risk factors. These prototypes were then evaluated in the field and their effects on the low back stress and productivity were quantified. The results of this analysis for three of these prototypes (a pneumatic wall lift, an extension handle for a pneumatic nail gun and a vertical lumber handling system) are presented in this paper. The pneumatic wall lift reduced peak spine compression by 63% and had mixed effects on productivity depending on the characteristics of the wall being erected. The extension handle for the pneumatic nail gun had a marked decrease in the average spine compression (73%) and also had mixed effects on the productivity depending on the characteristics of the support structures under the subflooring. The vertical lumber handling system created significant reductions in both the peak (70%) and average (32%) spine compression forces as well as a significant improvement in productivity (increase of up to 77%). Several of these interventions had positive effects in other body regions (primarily shoulder loading) but these were not quantified in the rigorous way that the low back stress was evaluated. Finally, subjective assessments by the workers varied across the interventions and were heavily weighted by their effects on productivity. Relevance to industry Engineering controls are the most effective methods for controlling work-related musculoskeletal disorders. This study evaluates the effectiveness of a set of engineering controls for the prevention of back injury/illness in framing carpenters.