In order to standardize results and to be able to compare one thermal switch to another, the industry has adopted a standard rate of temperature change which ranges from 0.25°C to 1.0°C change per minute. The larger and the more thermally resistive the package the slower the temperature rise rate must be. After the rise from room temperature a 10 – 15 minute soak at the lower threshold of the published range of operation is required in order to allow temperatures to stabilize. After the soak the specified temperature rise rate must be used and the contacts monitored closely to determine the correct operating temperature.