Occupational exposure to cold thermal environments: a field study in Portugal.

The present work is essentially dedicated to the study of cold thermal environments. The analysis includes 32 industrial units from 6 activity sectors and the measurements were carried out in 101 workplaces. Different environmental conditions were identified and a clear relationship with the different types of workplaces was established. The work environments were thus allocated to three typical exposure categories corresponding to freezing and refrigerating cold stores and free-running or controlled air temperature manufacturing workplaces. In order to characterize the level of cold exposure, the method proposed by ISO/TR 11079, Technical Report, 1st edn, International Organization for Standardization, Geneva (1993) was adopted. The results for each activity sector demonstrate that a significant percentage of workers are repeatedly exposed to extreme conditions with insufficient clothing insulation. A value between 20 and 40% corresponds to the most critical situation, where the selected clothing ensemble does not provide adequate insulation (I (clr) < IREQ (min)). The ideal scenario, represented by I (clr) values between IREQ (min) and IREQ (neutral), shows the lowest percentages with an overall result of only 10%. When all the sectors are considered together, from a total of 3,667 workers, about one-third (1,151) are exposed to the cold. Among the workplaces under analysis, 14 are characterized by a continuous exposure greater than the DLE (neutral). Those who work under such conditions, on average, have a time shift 60 min longer than the calculated DLE value.