04/08/2026
What is ASTM E595?
ASTM E595 is the internationally recognised test method used to determine the outgassing characteristics of materials exposed to high vacuum environments.
ASTM E595 was developed in response to the need to control molecular contamination on spacecraft. During the 1970s, NASA increasingly recognised that spacecraft and satellites had to be designed with outgassing risks in mind, particularly for materials used in high-vacuum environments where even trace contamination could compromise performance.
The standard established a consistent method for evaluating the outgassing characteristics of materials, helping determine whether they were suitable for use in contamination-sensitive applications.
The procedure measures:
- Total Mass Loss (TML)
- Collected Volatile Condensable Material (CVCM)
- Water Vapour Regained (WVR)
These measurements allow engineers to compare materials based on their tendency to release volatile compounds under vacuum conditions.
Find out more about the standard and our low outgassing thermal pads here: https://www.tglobaltechnology.com/2026/07/29/what-is-astm-e595/