O-Ring Shelf Life Recommendation per ARP 5316
O-Ring shelf life is the amount of "storage life" generally understood as the maximum time (beginning with manufacture date) that an O-Ring or Hydraulic Seal that is properly packaged and stored under specific conditions becomes "Expired" for its original purpose. Just like Milk, Chloroprene (Neoprene), Hydrogenated Nitrile, HNBR or HSN, Buna-N (Nitrile or NBR), Polyurethane (Polyester or Polyether) Millable and Industrial Cast Urethane have a shelf life and need to be put into service before the "Expiration Date". Most suppliers do not or will not provide you the information and could be unknowingly providing you expired product.
The O-Ring Store LLC "Certificate of Conformance" is available upon request. We certify this product has been manufactured in accordance to all required specifications, have been stored properly and are within usable shelf life limits. The Buna-N FDA, EPDM FDA, Silicone FDA and FKM FDA material meets the requirements of the U.S. Code of Federal regulations, Title 21 (Food and Drugs), Part 177, Subpart C Section 177.2600.
Elastomer and o-ring shelf life is governed by SAE International Standard ARP5316D, that calls out all aspects of o-ring shelf life.
Key elements of the ARP5316D standard include:
- Temperature - O-rings need to be stored below 100F (38C) and stored away from direct sunlight, and sources of heat (radiators, heaters, boilers), and above 59F (15C).
- Humidity - Relative Humidity shall be such the fluctuations in ambient temperature do not result in condensation. If elastomers are not in moisture proof bags, ambient Rh should be less than 75% (65% for polyurethanes).
- Light - O-rings and elastomers need to be shielded from direct sunlight, or lighting with ultraviolet content.
- Radiation - Elastomers should not come into contact with ionizing radiation.
- Ozone- Care should be extended to protect against contact with ozone, or ozone generating equipment, or combustible gases/vapors.
The ARP5316D standard also addresses good practices for handling o-rings and elastomers such as stock rotation, contact with metals, liquids or other elastomers, deformation and stresses, duration of storage and discarding of seals.
|O-ring Compound||ASTM||Shelf Life|
|Butyl Rubber, Isobutylene Isoprene||IIR||Unlimited|
|Chloroprene (Neoprene®)||CR||15 Years|
|Ethylene Propylene, EPDM or EP||EP||Unlimited|
|CV75 Extreme Chemical Resistant Fluorocarbon FKM||ETP||Unlimited|
|Hydrogenated Nitrile, HNBR or HSN||HNBR||15 Years|
|Buna-N (Nitrile or NBR)||NBR||15 Years|
|Polyurethane (Polyester or Polyether) Millable||AU / EU||5 Years|
|Urethane - Industrial Cast Polyurethane||EU||5+5 Years*|
|Styrene Butadiene (Buna-S)||SBR||3 Years|
|*Life may be extended after inspection|
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.
Age control of elastomeric seals and assemblies started after World War II on hydraulic, fuel and lubrication seals on aircraft. 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.
The O-ring Store LLC utilizes the last day of the quarter of cure as the time of manufacture. We can provide cure dates and certs on products if noted at time of purchase.
O-rings are shipped in sealed bags that are individually marked. O-ring Rebuild Kits and Assorted O-ring kits manufactured by The O-ring Store LLC are packaged for resale. We offer seals bags as standard, zip lock, anti-static, UV and Mil-spec packaging at an additional cost.
Information within is believed to be accurate and reliable. However, The O-Ring Store, LLC makes no warranty, expressed or implied, that parts supplied in this material will perform satisfactorily in specific applications. It’s the customer’s responsibility to evaluate the material prior to use.