Now that the engineer has reviewed some of the most commonly used thermal testing methods, the engineer will show an example of published thermal conductivity values. The example here is from a competitor showing products similar to Chomerics’ gap filler pads being tested by a transient state method as well as a steady-state method. Inside the blue box, the left hand column shows materials measured per ISO 22007-2, or the Hot Disk Method, and the right hand column measures per ASTM E1530, or the Guarded Hot Plate Method. For reference, the guarded hot plate method is similar to the Parallel Plate Method per ASTM D5470 and this competitor is one of the few suppliers who tests per the guarded hot plate method. For the designers purpose, one can assume this steady-state method would closely represent values measured through the parallel plate method. For each of the five products shown, the designer can see a discrepancy in thermal conductivity values. The differences in measurement cannot be correlated to a relationship that can be applied across the materials. It is important to recognize this when comparing datasheet values across different vendors. The values listed cannot simply be taken as true without testing the material per the same method with the same sample preparation and testing parameters.