Arbete i kyla vid mjölkproduktionsanläggningar: Kartläggning och studie av termiska arbetsmiljöproblem

The aim of the project was to analyse problems with cold when working in dairyfarms with respect to prevalence, frequency and risk for injuries and to propose measures for improvements of thermal conditions. The project comprised two parts: a field study and a questionnaire survey. The field studies were performed at seven dairy-farms in the Uppsala region and six dairy-farms in the northern region of Sweden (Vasterbotten). Four of the farms in the Uppsala region were non-insulated loose housing barns, one was an insulated loose housing barn and two had traditional barns with tie stall. In Vasterbotten, five of the farms were non-insulated loose housing barns and one was an insulated loose housing barn. In total, 20 farmers were studied during milking and animal feeding and maintenance. The majority of the studied farmers were owners of the farm and family members. During the field study, both physiological and physical measurements were performed. In addition, a detailed observation of the work, which enabled linking of measured data and the work tasks that were carried out. The physiological measurements included skin temperature of different body parts and heart rate. All subjects and their clothes were weighed before and after work in order to estimate sweating and evaporation. Further, the energetic workload was measured at the farms in Vasterbotten. The physical measurements concerned air and surface temperature and air velocity in the buildings where work was performed as well as outdoors. A questionnaire was sent to 140 dairy-farms in the northern part of Sweden. The questions concerned problems and discomfort that may be related to cold, for example, how cold affected the work, problems with clothing, gloves and footwear. As was expected, the study showed that cold might cause considerable stress for dairy-farmers during cold weather. However, problems with cold should be viewed in a larger context. Workers in dairy-farms are exposed to several physical and physiological stressors in the work environment, such as moisture, organic dust, musculoskeletal stress and mental stress. During winter, cold adds to these stressors, which increases the environmental load on the individual. The typical climate in the raised milking parlours was as follows: low air temperature, which was lowest at foot level, high humidity, moisture, frequent draught and low surface temperatures. Hands and fingers often became cold during milking. The hands were often 20-25 °C. Especially the finger temperatures dropped to low levels during milking. In many cases it was below 16 °C for almost the whole spell of work. Finger temperatures down to 6 °C were observed at the end of the milking period in milking parlours with a non-insulated holding area, and 9 °C in milking parlours with an insulated holding area. In many cases, foot and toe temperatures dropped to unacceptably low levels. The reasons for cold feet were reported to be the result of inadequate footwear. This problem was probably related to the fact that rubber boots without an insulation layer were very common among the farmers. The second most common problem was sweaty or wet feet. An important way to be protected from cold is to use adequate clothing. Cotton, which absorbs moisture and water well, was a very common material in the garments worn by the farmers. For the outer layer of the clothing, a water-repellent material is a better alternative in cold-wet environments. At heavy work, which results in sweating, cotton is not the most appropriate material to wear close to the skin. Sweat is absorbed by the cotton and thus stays at the skin. This leads to discomfort and feels cold when heavy work changes to light work, or when the worker moves outdoors. Many commercial non-absorbing materials, which may contribute to better thermal comfort, are available. When using underwear made of such materials, the moisture is transported away from the skin to other clothing layers. Both the survey results and the observations indicated that cold was experienced as a minor problem in farms with non-insulated loose housing barns even though most of the participating farms were situated in one of the coldest regions of Sweden. In non-insulated loose housing barns, the work and the protection from cold is most likely adjusted to the cold climate, and temperature changes may lead to less discomfort, at least, for that reason. Greater experience of work in cold conditions probably contributes to a work organisation that minimises cold problems. In traditional barns, temperature changes between buildings and outdoors are common and were considered a major cause for thermal discomfort. Based on the results from this study, recommendations have been worked out. They provide a long list of interventions to prevent cold hands and feet, advice about clothing and other measures for improvements of the thermal conditions.