O-Ring Shelf Life

O-Ring Shelf Life Compliance Standard

Global O-Ring and Seal adheres to the SAE International Aerospace Standard AS5316 for all elastomer product shelf life and storage conditions. Previously known as ARP5316 (Recommended Practice), this standard is based upon both cumulative studies and industry input regarding practical storage limits and FIFO requirements. Please note compliance to this standard is voluntary – Global O-Ring and Seal meets all customer requirements set forth. These limits are based on examination and testing of rubber seals with extensive shelf age, in some cases more than 30 years. In addition to practical experience, these recommendations also conform to theoretical expectations: those materials with unlimited shelf lives show no chemical potential for degradation due to atmospheric exposure and are chemically and physically stable.

O-Ring Shelf Life Recommendation per AS5316

The chart below provides the recommended shelf life for various materials of elastomer (rubber) seals, per SAE’s Aerospace Recommended Practice ARP 5316. Global O-Ring and Seal has accepted ARP 5316 as the most comprehensive basis for establishing shelf life, however, it is not a binding Specification. This information is to be used simply as a basis upon which companies can form their own shelf life requirements.

*Note AS5316 deals only with the storage of elastomeric parts and carries no justification for components post application/assembly

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Storage Conditions:

Proper storage conditions are pivotal to ensure the shelf life standard of the above-stated materials are met. Listed below are various factors that can affect shelf life followed by the AS5316 requirement.

Temperature: Storage temperature must be between 59°F (15°C) and 100°F (38°C).

Humidity: – Relative Humidity (RH) must be less than 75% unless stored in sealed moisture proof bags.

Light: Material must be protected from direct sunlight and/or intense artificial light having U.V. content.

Radiation: All precautions must be taken to block sources of ionizing radiation likely to cause damage.

Ozone: Storage room shall be free of any equipment that may generate ozone (mercury vapor lamps or high voltage electrical equipment) or combustible gases/vapors.

Deformation: Material shall be stored in a strain-free condition, avoiding stress and other causes of deformation.

Dissimilar Materials: Avoid contact with other materials such as liquids or semi-solids (gasoline, grease, acids, disinfectants, cleaning fluids), metals (copper, manganese, iron), and other elastomers.

Packaging Requirements:

ARP 5316 recommends individual packaging of rubber seals to protect them and maintain batch traceability. We have found that our bulk packaging accomplishes the same. In addition, the data utilized by the SAE committee was based on the examination of 32-year-old seals. No differences were found between bulk packaged and unit packed seals in this study. Therefore, we feel that unit packaging is not critical for attaining the stated shelf lives; however, it will be available at customer request.

Cure Date:

ARP 5316 does not mention the quarter of cure, but instead refers to the “time of manufacture.” At Global O-Ring, we utilize the last day of the quarter of cure as the time of manufacture.

History:

Age control of elastomeric seals and assemblies started after World War II on hydraulic, fuel and lubrication seals on aircrafts. The first document on age control was released in 1958 and was a compilation of several studies on age control done since WWII. After several more studies and papers, MIL-STD 1523 was released in 1973 and gave 12 quarters as maximum shelf life. This was extended to 40 quarters in 1984 with the release of MIL-STD-1523A. This standard was cancelled in 1995 when the release of AS1933 was issued. AS1933, “Age Controls for Hose Containing Age-Sensitive Elastomeric Materials” only addressed elastomeric hoses and seals were essentially released from control.

In the past, MIL-HDBK-695C, MIL-STD-1523A, and its replacement, AS1933, were applied to rubber seals. MIL-STD-1523A was cancelled in 1995; the cancellation notice referred to AS1933 as a potential replacement. However, AS1933 specifically deals with rubber hose, and does not deal directly with the concerns of the seal industry. In like manner, MIL-HDBK-695C applies to any and all rubber goods — but does not satisfy the needs of the seal industry. ARP 5316 was written to “fill the void” and provide a foundation upon which seal manufacturers, distributors, and users could generate realistic shelf life criteria.

Summary:

Because ARP 5316 represents the latest and most accurate information concerning shelf life of elastomer seals, Global O-Ring and Seal recommends that all distributors and customers work to incorporate the new guidelines in the most appropriate manner. ARP 5316 is a copyrighted document. Copies of ARP 5316 may be purchased from SAE by calling (724) 776-4970 or at http://standards.sae.org/arp5316c/.

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