The thermometers for extreme cold do not differ, neither in their external appearance nor in their accuracy, from standard instruments for ambient temperatures down to -40 °C. However, these are individual solutions made of application-specific and appropriately cold-resistant components.
Each ready-to-use thermometer and its components are tested, in line with the requirements, at a test temperature of -70 °C, for thermal shock resistance in accordance with IEC 60079-0 and for an IP protection in accordance with IEC 60529. An impact resistance test is added with the assembled instrument. The qualification for low ambient temperatures is confirmed on the delivery note.