How Do I Calculate Shelf Life of O-Rings and Seals?

The information in the calculator and chart below, is ESP’s recommendation based on the AS5316 standard and intended to be utilized by those organizations who do not already have specific recommendations for the control of elastomeric seals. It should be noted that the packaging of the elastomeric seals prior to assembly into a product is an integral part of the controlled storage procedure. It provides a positive means of product identity from the time of manufacture to the time of assembly.

ESP does not establish limitations for storage times in assembled components, nor does it in any way provide a guideline for the operating life span of a particular compound.

The Shelf Life of the elastomer compound is dependent on the polymer type and storage conditions. Complete details of recommended storage conditions can be found within SAE AS5316.

What Is Shelf Life Of O-Rings And Seals?

"Shelf life" is the maximum time (beginning with manufacture date) that an o-ring or elastomeric seal – with proper packaging and storage, becomes unable to meet its original specifications.

In 1998, the SAE International issued Aerospace Recommended Practice (AS) 5316. It was intended to fully replace MIL-HDBK-695C as the industry standard for the Shelf Life of Aerospace elastomeric seals. However, AS 5316 can also be used as a useful guideline for Shelf Life of many industrial and commercial grade elastomers as well. Aerospace Recommended Practice (AS 5316) is the most comprehensive basis for establishing shelf life, however, it is not a binding specification.

ESP Shelf Life Chart Based On AS 5316 Elastomer Shelf Life Recommendations:

Aflas® is the registered trademark of Asahi Glass Company, Limited
Neoprene® is a registered trademark of Denka Performance Elastomers
Vamac® is a registered trademark of E.I. du Pont de Nemours & Co
Viton® is the registered trademark of DuPont Performance Elastomers

How Should I Package O-Rings And Seals?

AS5316 recommends that elastomeric seals be packaged individually. Based on our experience, we have found that bulk quantities have the same results. As long as packing materials are free of elements that can degrade rubber, such as copper naphthenates or creosote preservatives.

How Should I Store O-Rings And Seals?

The proper storage is vital to maintain the full shelf life of an elastomeric seal. Several key factors should be taken into consideration when storing. These ESP recommendations are based on AS5316 requirements.

Factors to consider when storing o-rings and seals:

1. Temperature: Store your parts between 59°F (15°C) and 100°F (38°C).
2. Humidity: Make sure condensation does not occur resulting from variations of temperature in storage. If not packaged in sealed moisture-proof bags, the relative humidity (r h) should be less than 75% r h - less than 65% r h if it is a polyurethane.
3. Light: Protect seals from direct sunlight and intense ultraviolet light. Opaque bags offer the best protection.
4. Radiation: Protect seals from sources of ionizing radiation.
5. Ozone: Remove any equipment that may generate ozone (mercury vapor lamps, high-voltage equipment) as well as combustion gases and organic vapor.
6. Deformation: Store seals away from stresses and tensions that could cause deformation such as creasing or twisting.
7. Unwanted Contact: Avoid elastomeric seal contact with other materials such as liquid and semi-solid materials (gasoline, greases, acids, disinfectants, cleaning fluids) or their vapors, metals (copper, manganese, iron), dusting powder, different polymeric elastomers, and elastomeric seals bonded to metal - they should be individually packaged.
8. Stock Rotation: Stock should be rotated by "first in - first out" so that the older parts are used more timely.

AS 5316 is a copyrighted document. Copies of AS 5316 may be purchased from SAE by calling (724) 776-4970 or at https://www.sae.org/standards/