Comparison of Worker Safety Risks between Onsite and Offsite Construction Methods: A Site Management Perspective

AbstractMany researchers, as well as industry practitioners, believe that offsite construction methods are associated with a lower level of worker safety risks than traditional onsite construction methods. This study aims to test such belief by comparing the list of worker safety risks identified by site supervisors for both onsite and offsite construction scenarios for the same building components. Specifically, Safe Work Method Statements (SWMS)—prejob hazard assessments required by law in Australia—were collected from two projects where offsite manufacturing has been used, and they were used as a basis for the investigation. Additionally, interviews were conducted with the site supervisors who developed the Statements for a more in-depth investigation of the worker safety risks involved with onsite and offsite construction methods, respectively. The analysis reveals that the total risk score (the higher the score, the more numerous the safety risks) would decrease in the offsite construction scenarios in each case, mainly due to significantly fewer work-at-height tasks included in the offsite construction scenarios. This study contributes to the body of knowledge by providing an empirical, evidence-based explanation for why offsite construction can help reduce safety risks on construction sites.