[Preliminary comparison of 2 indices of the microclimate: correct effective temperature and SWBGT (Swedish wet-bulb-globe temperature index)]

The CET and the SWBGT indices have been jointly assessed in 200 working places of 17 mechanical engineering shops and factories in Northern Italy. In the climatic conditions that have been met in the investigation (low air velocity, medium-high humidity, moderate to medium thermal stress with significant radiant heat), the indices proved to be correlated (r = 0.81) by the following regression equation: SWBGT = 0.99 CET -- 1.67, and the scattering of individual values was rather narrow. The SWBGT appears to be of more practical application than the CET and it reflects more adequately the adverse effects of low air velocities, therefore improving the adequacy of the index especially in humid environment. However, including a unique correction factor for low air velocity, it does not fit well with climatic conditions where air velocity approaches 0.5 m/s. The SWBGT requires that all four climatic parameters be determined without spending more time for the analysis than the WBGT. In different combinations of climatic conditions from those which have been met in the investigation the results may differ; however, from these preliminary observations it is suggested to further the comparison with the assessment of metabolic load and physiological response.