Temperature limit values for cold touchable surfaces ' ColdSurf ' : final report

The aim of the project was to find and compile information on human responses to contact with cold surfaces. The work has covered 1) literature search and field survey; 2) experimental studies with human subjects; 3) simulation by modeling; 4) instrumentation (artificial finger), 5) establishment of database and 6) proposal of a draft standard for cold touchable surfaces.
The field survey in food processing industries has showed that the cold hazards in hands, especially fingers, often occur. The experimental results with human subjects indicate a more rapid reduction in contact temperature when finger/hand contact metallic surfaces compared to non-metallic surfaces, such as stone, nylon and wood. The temperature drop was found to be function of skin and material surface temperature, material and skin properties and contact conditions (pressure, area). Manual performance (tactile sensitivity/finger dexterity) decreased after gripping cold rods. The safety criteria for contact temperature are suggested to be 0 °C for freezing cold injury, 7 °C for numbness and 15 °C for pain sensation. The time to reach these criteria when touching or gripping cold objects of different material has been determined and compiled in a database. An analytical, mathematical model was derived and an artificial finger was developed to derive additional cooling information for very cold conditions under which no human experiments could be performed. The results of the project have been issued in a document that can serve as a basis for the development of an ergonomics database by appropriate standardisation bodies (TC122/WG3). The standard is applicable for all fields where cold surfaces cause a risk of hand/finger contact cooling.