Difference of actual handled weight and the recommended limit for dynamic asymmetrical manual handling tasks in chilean construction workers

Abstract

Manual handling is a risk factor with high attributable fraction in lumbar pain, frequent injury among construction workers due to dynamic and complex tasks. The aim of this study was to establish the differences between the actual handled weight and the recommended weight limit (RWL) according to EC2 (Ergo Carga Construcción) evaluation method. The study was an analytic and non-experimental cross-section carried out in 32 construction sites with a sample of 186 workers. The positions assessed were bricklayer, scaffolding assembler, carpenters, hand laborers, construction laborers (excavation laborer/safety carpenter) and ironworkers during weight handling tasks. The EC2 method is designed to assess Dynamic Asymmetrical Manual Handling Tasks (DAMHT) and as result, estimates the Recommended Weight Limit (RWL) per task. Within the group 179 DAMHT were assessed. In the sample the actual handled weight was between 3 kg and 80 kg, with a median of 20 kg (ICR = 20 kg). Meanwhile the values of the RWL were between 1.8 kg y 28.7 kg, with a median of 7.31 kg (ICR = 3.37 kg). Generally, all positions handle weights above the RWL established by EC2. The analyzed sample has a difference of 10.98 kg (ICR 23.4), between the actual handled weight and the RWL. The exception are the construction laborers (excavation laborer/safety carpenter), who present a negative difference, while hand laborers (15.69 kg/ICR 25.84), bricklayer (15.17 kg/ICR 23.28) and ironworkers (10,7 kg/ICR 24,62 kg) presents the highest difference among the group. Contrasting research data with limits allowed by Chilean Law (Law 20.949 – maximum limit of 25 kg), a 33% of the sample performs DAMHT above lawful limits. 5% handle weights above 50 kg with a maximum of 80 kg. Regarding the RWL 83.2% of the manual handling observed is above this limit, therefore they imply high physical workload, thus the intervention must be not only with a technical approach but with administrative and engineering actions.