The impact of Kaizen on safety in modular home manufacturing

High injury and fatality rates prevalent in all types of construction in the USA may be addressed by combining safety initiatives with process improvement through Lean. This study evaluated the impact on worker safety when Kaizen (a Lean tool) was used at a modular homebuilder. Twelve students who had completed a safety course and four safety experts rated the probability and severity of hazards (as determined by a job safety analysis, or JSA) present in three workstations; base-framing, sheet rock hanging, and painting. These ratings were provided after viewing a series of photographs taken before and after a Kaizen event performed at each workstation. The rating tool showed high reliability for all safety experts' ratings but only for students' ratings from the sheet rock hanging station. Students' and experts' ratings showed a significant reduction in risk in the base-framing station after the Kaizen, and student's ratings showed significantly reduced risk in the sheet-rock hanging station. Kaizen has the potential to improve safety in modular homebuilding and possibly, other manufacturing and construction activities.