Análisis del efecto del estrés térmico en el rendimiento laboral y su incidencia en los costos de una obra vial en el cantón la joya de los sachas: propuestas de mejora

Abstract

The study analyzed the effect of heat stress on the performance of a crew of workers responsible for laying asphalt mix and its impact on construction costs. As a first step, the jobs that were exposed to heat stress were evaluated using the NTE INEN-ISO 7243:2023 methodology. It was found that the jobs of “rake operator” and “shovel operator” were the most exposed to heat stress, with WBGT values of 30.19 °C and 30.31 °C, respectively, followed by the “roller operator” with a moderate risk, with a WBGT of 28.96 °C. Finally, the “asphalt paver operator” showed limited exposure, with a WBGT of 30.13 °C, indicating highly acclimatized personnel. The crew's performance was recorded during the 13 days that the asphalt mixture was laid on the road. After that, a Spearman correlation test was applied between heat stress (WBGT) and performance (h/m²), obtaining r factors between (-0.269 and -0.327). This implied a weak inverse correlation, i.e., an increase in thermal load tends to slightly decrease performance. However, p values > 0.05 determined that there is insufficient statistical evidence to affirm a significant effect of thermal stress on performance. For the cost ratio, an average performance of 0.004 h/m² (hours to lay 1.00 m² of asphalt mix) was obtained for the crew, which was higher than the contractual performance of 0.001 h/m², generating a surplus of USD 13,939.20 for the contractor. However, these productivity levels are not sustainable over time, as they were achieved under conditions of heat stress. Consequently, an improvement plan was drawn up, with measures in line with the reality of the company and the hierarchy of operational controls, for each job position and others common to the entire crew.