Construction workers remote estimate of the wbgt index in outdoor activities on concrete slabs

In the last years, climate changes have been frequent, especially regarding to the increasing of annual temperature average. Special attention shall be given to work activities performed in outdoor spaces where the worker is exposed to solar radiation, as is the case of construction workers. Environmental condition combined with body heat production due to activities and clothing insulation hinders thermal balance, raising body core temperature to values above 37°C that may result in thermal overload conditions, causing injuries to worker's health. In order to avoid the mentioned situation, there is the need of constant heat exposure monitoring, which is complex due to the need for difficult displacements, expensive monitoring equipment and trained personnel. In this context, the general objective of this thesis was to propose an estimation method to obtain the Wet Bulb Globe Thermometer Index (WBGT), based on meteorological data from automatic stations of the National Institute of Meteorology (INMET, in Portuguese). This is a descriptive and analytical research with collection and analysis of quantitative and qualitative data in building construction works and, simultaneously, in areas of grassy surfaces in Campinas city, São Paulo state, Brazil. Meteorological data were obtained from March / 2017 to March / 2018, using environmental variables measuring equipment (natural wet bulb temperature-Twb, dry bulb temperature-Tdb, black globe temperature-Tg, air humidity, wind velocity, radiation and surface temperature). These data were analyzed using multiple linear regression method, being obtained predictive equations of Twb and Tg for the WBGT Index estimation, from meteorological variables, as results. Qualitative data (age, gender, weight, height, metabolic rate, clothing and protective equipment of workers), collected through interview and observation of workers whose activities over open slabs were performed, were analyzed together with WBGT in exposure assessment in accordance with the Regulatory Standard (NR, in Portuguese) number 15 - Unhealthy Activities and Operations - issued by the Brazilian Ministry of Labor. The characterization of the workers' sample showed an average surface area close to the standard value of the international standard. From the composition analysis of the workers' body movements performance, metabolic rates average were obtained, data that allowed the classification of the activities as moderate and heavy for the following professional functions: carpenter, rebar worker, bricklayer and assistant. Heat exposure assessment pointed out the need its monitoring practice and work breaks with the purpose of enabling workers' body thermal recovery at certain periods of the day, even if breaks affect work pace, regardless of the season. Predictive equations for WBGT estimation with meteorological data, considering slab concrete surface, presented good correlation (R²> 0.70). With both estimate and monitoring practices of heat exposure conditions, it is possible to plan actions in order to prevent and manage environmental risks, avoiding thermal overload conditions and helping to preserve safety and health conditions of building construction workers. Keywords: Heat stress. Outdoor activities. Building construction. Meteorological data. Occupational exposure to heat.