Forecasting labor productivity changes in construction using the PMV index

Abstract

Over the years, many attempts have been made to establish mathematical models reflecting the relationship between the thermal environment and construction labor productivity. Once established, the models were used to forecast the change in productivity due to thermal environment variations. The models, however, failed to accurately capture the complex nature of such a relationship for a number of reasons, including a consideration of the nature of the task being performed and the effect of all known variables of the thermal environment. This paper briefly describes and highlights the main shortcomings of three established thermal environment/productivity forecasting models. It introduces a fourth model, developed by the authors, where productivity can be predicted as a function of the PMV index. The paper then presents a comparative analysis between all four models with emphasis on their sensitivity to air temperature. Field data collected from different construction sites demonstrate that observed productivity data agree well with those predicted by the PMV-based model. Relevance to industry To many, a construction project is considered successful if it is completed within its scheduled duration and estimated cost. Considering the various elements of cost, there would be general agreement among estimators that the element subject to most variability is the labor cost which is a function of two factors namely, unit cost of labor and labor productivity. The latter is subject to most variability due to being dependent upon many factors including thermal environment variations. Therefore, a proper evaluation of the effect of thermal environment on labor productivity is needed to estimate construction costs and schedule or to quantify damages resulting from productivity losses in construction claims.