As it relates to the internal chemical degradation of elastomer performance properties over time, the term “aging” is misleading. In fact, it is the exposure of o-ring elastomers to stressful environmental factors during storage that ultimately causes changes in performance properties over time.
Based on ARP5316, which addresses general requirements for data recording, packaging and storing aerospace elastomeric seals, the following conditions are recommended:
- Ambient temperature not exceeding 120°F.
- Exclusion of air (oxygen).
- Exclusion of contamination.
- Exclusion of light (especially ultra-violet).
- Exclusion of ozone-generating electrical devices.
- Exclusion of radiation.
- Storage of o-rings in sealed polyethylene bags, inside cardboard containers helps assure maximum shelf life.
Note: The MIL-STD-1523A (“Age Controls of Age-Sensitive Elastomeric Material”) which relates to “cure dating” for seals was canceled on January 30, 1995. When a seal is stored properly, age is no longer considered a factor in seal failure.