Seals fail for many reasons, including long-term storage in less than ideal conditions. Rubber can crack, harden, soften, or degrade in ways that make it unsafe for its intended use. Most seals have a widely accepted shelf life, which helps manufacturers prevent catastrophic failure due to an old seal.
Maintaining seals throughout their intended shelf life involves providing a storage environment free from light, oxygen, ozone, and chemicals. Excessive heat, freezing temperatures, and physical impact may cause permanent damage to elastomers, rendering them useless. Be sure to check elastomeric products before installation to confirm that they are in good serviceable condition. Hardening, softening, stickiness, cracking, and discoloration all indicate that there may be a problem with the seal.
What is Shelf Life?
Shelf life is the maximum amount of time an appropriately packaged seal is expected to last between the time of manufacture and the time the seal is put into use. Shelf life varies according to the type of seal. When a seal has been in storage longer than its shelf life, even under ideal conditions, it is no longer serviceable for its intended purpose.
The Society of Aerospace Engineers (SAE) Standard ARP 5316 provides the maximum recommended shelf life for specific types of industrial seals. ARP 5316 is also a useful standard when determining the shelf life of elastomers used across many industries.
ARP 5316 Elastomer Shelf Life Recommendations by Time
Shelf Life Recommendation: Unlimited
• Butyl Rubber, Isobutylene Isoprene IIR
• Ethylene Propylene, EPDM, or EP
• Fluorocarbon (Viton) FKM
• Fluorosilicone FVMQ
• Perfluoroelastomer FFKM
• Polytetrafluoroethylene (Teflon) PTFE
• Silicone VMQ
Some manufacturers consider an unlimited shelf life equivalent to 25 years. Even under less than ideal storage conditions, elastomeric products in this category do not typically degrade over time. Long-term storage of industrial seals with an unlimited shelf life should be indoors. The controlled environment should have humidity levels below 65% and temperatures between 59 degrees and 77 degrees Fahrenheit.
It is crucial to keep all industrial seals in their OEM packaging and out of the sunlight to protect seals from ozone, oils, and solvents.
Shelf Life Recommendation: 15 Years
• Chloroprene (Neoprene) CR
• Ethylene Acrylic (Vamac) AEM
• Hydrogenated Nitrile, HNBR or HSN HNBR
• Nitrile (Buna-N or NBR) NBR
• Polyacrylate ACM
While elastomeric products in this category also have a long shelf life, proper storage helps to ensure their effectiveness when put into service during their recommended shelf life. Like seals with an unlimited shelf life, seals in the 15-year category should be kept in a controlled environment away from sunlight and solvents. Ideally, the storage area would also be between 59 degrees and 100 degrees Fahrenheit with humidity levels below 75%.
Shelf Life Recommendation: 5 Years and Below
• Polyurethane (Polyester or Polyether) AU / EU
• Styrene Butadiene (Buna-S) SBR
• Urethane - Industrial Cast Polyurethane EU
Materials with a shelf life of five years and below require certain storage conditions to prevent deterioration of the product. Select a storage environment with an ambient temperature between 59 degrees and 100 degrees Fahrenheit. Protect the product from sunlight, ozone generating electrical devices, radiation, and oxygen when possible. Freezing temperatures may cause the rubber to harden and distort. Most elastomer seals return to their normal shape as temperatures rise. Excessive heat can cause premature deterioration of rubber, but the negative effects of excessive heat are permanent.
How working with Wyatt Seal can reduce the potential pitfalls of a Shelf Life Requirement
In general, lower volume items should be sourced in smaller batches to preserve the integrity of the seals. In the US, most manufacturers stock smaller quantities or carry no inventory to prevent their product from becoming outdated. That is why there is a strong advantage to working with a distributor like Wyatt Seal, who can manage inventory levels for you and ensure all products stay within shelf life requirements.
Here at Wyatt Seal, we work closely with our manufacturing partners and only make material recommendations based on customer needs. When we understand how and when our customers use our products, we can plan to keep the right amount of inventory on hand to meet their requirements.
We use first-in/first-out inventory management practices so our partners never receive seals that are past their shelf life requirements. In many cases, we have multiple customers using the same standard parts and materials, which helps us maintain appropriate stock levels and keeps our inventory within shelf life requirements.
Industrial seals remain usable even if they are in storage for long periods of time. Following basic guidelines regarding the ambient temperature and exclusion of light among other recommendations for storing industrial seals helps to ensure the product's long-term shelf life. Reach out to a Wyatt Seal representative today for more information on how we can help you manage your inventory and shelf life requirements