New Method for Measuring the Safety Risk of Construction Activities: Task Demand Assessment

TLDR

The task demand assessment (TDA) is a new technique that quantifies the safety risk of construction activities by measuring task demand—based on hazard exposure and observable risk factors—rather than estimating incident probabilities, thereby reflecting the difficulty of performing tasks safely. This study presents initial implementation results of TDA, demonstrating its feasibility on roofing and concrete paving operations while outlining its limitations and the need for further research. The findings show that TDA can be applied to activities of varying complexity, compare production scenarios, quantify the impact of production variables on accident potential, and serve as a useful tool for researchers and practitioners.

Abstract

The task demand assessment (TDA) is a new technique for measuring the safety risk of construction activities and analyzing how changes in operation parameters can affect the potential for accidents. TDA is similar to observational ergonomic methods—it does not produce estimates of probabilities of incidents, but it quantifies the "task demand" of actual operations based on characteristics of the activity and independent of the workers' capabilities. The task demand reflects the difficulty to perform the activity safely. It is based on (1) the exposure to a hazard and (2) the presence and level of observable task demand factors—that is, risk factors that can increase the potential for an accident. The paper presents the findings from the initial implementation of TDA and demonstrates its feasibility and applicability on two different operations: a roofing activity and a concrete paving operation. Furthermore, the paving case illustrates how the TDA method can compare different production scenarios and measure the effect of production variables on the accident potential. The findings indicate that the method can be applied on activities of varying complexity and can account for several risks and task demand factors as required by the user. The selection of task demand factors is a key issue for the validity of the method and requires input from the crew and safety management. The limitations of the methodology and the need for further research are discussed. Overall, TDA provides a tool that can assist researchers and practitioners in the analysis and design of construction operations.