Off-gas testing

Off-gas testing is done on assemblies going into sensitive particle detection equipment. It is critical that these assemblies do not emit any gases or vapours from the assembly process. This would corrupt the analysis done by the machine.

Visualize a liquid, such as water in a swimming pool. Imagine dropping a sugar cube into a body of water the size of three Olympic size swimming pools. That is the level of sensitivity required for off-gas testing.


Macfab’s off-gas testing is isolated within our ISO 7 cleanroom

Even with that barrier in place, we have a strict company policy on fragrances entering the manufacturing space. If a person were to wear perfume, cologne, or even a scented deodorant on the manufacturing floor, the off-gas test might be contaminated.

Off-gassing can be caused by several reasons:

  • Physical evaporation of volatiles trapped inside the polymer volume, such as the evaporation of residual solvents or adhesives
  • Evaporation of the solvents from the external surface of the part, such as drying of paint or varnish
  • Slow chemical reactions during the curing of silicone sealant

When is Off-Gas Testing Required?

This testing requirement can be found in many industries. This level of validation is needed for parts going into medical and pharmaceutical machinery. Macfab conducts this testing to ensure the parts installed in the machinery will not contaminate people or products. Security and defence products that utilize gas-spectrometry to determine the safety of packages cannot afford to have gases venting from seals generating false positives. We inspect assemblies to verify that the seals or gaskets are not emitting gases. For space components, NASA maintains a standard (NASA-STD-6001) to make sure gases do not accumulate within a spacecraft.

How is Off-Gas Testing Done?

Macfab offers tests ranging from a few hours to a couple of days. The tests are performed at normal or elevated temperatures. The relative humidity of the test air in contact with the sample can be adjusted, from 0% to ambient, and up to 80% RH. Gases and vapours emitted from the sample can be tested as “total vapours” or individually. If the chemical composition of the emitted vapour is unknown, we can identify the individual vapours.

Component Sizes

Macfab’s off-gas testing chambers can accommodate an extensive range of parts. Most sub-assemblies receiving off-gas testing are small and can easily fit into the chamber. With Macfab’s fabrication work, including panels and structures for satellites, we can comfortably test enclosures the size of a shoebox.

Macfab’s engineers and quality experts are prepared to review your application’s requirements and work on determining validation tests. We look forward to discussing this highly critical testing procedure for your parts with your experts.