Heat resistance tests

Heat resistance is a measure of the thermal endurance of plastic materials. It describes the ability of a test specimen to retain its shape up to a specified temperature under a specified load or to deform only within specified limits at a specified test temperature.¹

The heat resistance can be determined according to various standardised test methods such as Vicat and the Heat distortion temperature.

The UL Thermoplastics Testing Center can carry out the following heat resistance tests for you.


Heat resistance test methods Standards
Vicat UL 746A
ASTM D1525
ISO 306
Heat distortion temperature (HDT) UL 746A
ISO 75-1/2
Ball pressure test UL 746A
IEC 60695-10-2




1 Grellmann, W., Seidler, S. (Editors): Kunststoffprüfung
  Carl Hanser Verlag, Munich/Vienna (2011)
  2nd Edition, pp. 591/592, (ISBN 978-446-42722-8)