scope:

NEN-EN 1427 specifies a method for the determination of the softening point of bitumen and bituminous binders in the range of 28 °C to 150 °C. Technical warning - The change from mercury thermometers to electronic temperature devices has revealed that the temperature definition in the mercury thermometer has not been precise enough to make a correct, unbiased transfer to electronic devices. Care should be taken for softening points ring and ball above 100 °C as the condition may have changed from previous practise to present days testing equipment. Below approx. 100 °C the difference in temperature readings between electronic and mercury stem thermometer is acceptable compared to the repeatability of this test methods. [Reference: ASTM E20 Group]