What Is Seal Shelf Life? Storage, Aging, and Older Seal Inventory
Learn what seal shelf life means, how storage conditions affect O-rings and seals, and what to review before using older seal inventory.
What Is Seal Shelf Life and Why Does It Matter?
O-rings and other seals may remain in inventory for months or years before they are installed. This often raises an important question:
How long can a seal be stored before it should no longer be used?
The answer depends on more than the age of the part.
Seal shelf life is influenced by the material, packaging, storage environment, applicable specifications, manufacturer guidance, customer requirements, and the demands of the final application.
Watch the Clip
In this 6-minute clip from The O-Ring and Seal Show, we discuss what seal shelf life generally means, how storage conditions may affect elastomer seals, and why age alone does not always tell the full story.
What Does Seal Shelf Life Mean?
Seal shelf life generally refers to the recommended period that a seal may remain in storage under appropriate conditions before additional review may be needed.
Shelf life should not automatically be treated as a guaranteed expiration date.
Reaching a recommended shelf-life date does not necessarily prove that a seal is unusable. Likewise, being within a recommended storage period does not guarantee that a seal is suitable for every application.
The requirements that apply to a specific seal may come from several sources, including:
- The seal manufacturer
- The material manufacturer
- An industry or customer specification
- A drawing or purchase order
- The end-use application
- Internal quality procedures
These requirements should be reviewed before making a decision about older inventory.
What Affects the Shelf Life of a Seal?
Different sealing materials may have different aging characteristics. Shelf-life guidance may vary for materials such as nitrile, EPDM, silicone, FKM, neoprene, polyurethane, and other elastomers or polymers.
Storage conditions also matter.
Potentially harmful conditions may include:
- Excessive heat
- Direct sunlight or ultraviolet exposure
- Ozone exposure
- Moisture or chemical contamination
- Poor or damaged packaging
- Stretching, compression, or physical distortion
- Contact with incompatible materials
Two identical seals manufactured at the same time may not remain in the same condition if they were stored in different environments.
When Does Seal Shelf Life Begin?
The date used to calculate shelf life depends on the applicable standard, manufacturer guidance, customer specification, and agreed-upon order requirements.
For many elastomer seals, shelf-life guidance is tied to the time of manufacture or cure date. However, the way that date is identified or recorded may vary by manufacturer or governing specification.
A date printed on the packaging should therefore be reviewed in context. It is important to understand what the date represents and which shelf-life requirement applies before making an acceptance or use decision.
Does an Older Seal Need to Be Discarded?
Not necessarily. However, a seal that has reached or exceeded the applicable recommended shelf-life period should be evaluated in accordance with the governing specifications, customer requirements, manufacturer guidance, and application needs.
Depending on the governing requirements, the review may include examining available documentation, checking packaging and storage history, consulting the manufacturer or customer, conducting any specifically required inspection or testing, or replacing the product. The appropriate action should be determined by the applicable specification, quality process, and application requirements.
Visual appearance alone should not be relied upon to establish suitability for use because some changes in material condition may not be readily visible.
Why Seal Shelf Life Matters
A seal’s condition can affect installation and performance.
Depending on the material and application, age or poor storage may contribute to concerns such as:
- Hardening or loss of elasticity
- Cracking or surface deterioration
- Permanent deformation
- Installation damage
- Leakage
- Reduced service life
These concerns may carry greater risk in critical, regulated, high-pressure, safety-related, or difficult-to-access applications.
This is why shelf-life questions are best addressed before the seal reaches assembly or installation.
Questions to Ask About Stored Seals
MaterialsWhen reviewing older seal inventory, useful questions may include:
- What is the seal material?
- Is the material identification documented?
- What date information is available?
- What does that date represent?
- How was the seal packaged?
- Where and how was it stored?
- Has the packaging been opened or damaged?
- Which specification or customer requirement applies?
- Is the application critical or regulated?
- Is inspection, testing, approval, or replacement required?
The answers may help determine which additional parties or requirements should be consulted.
How Performance Seals Can Help
Performance Seals understands that shelf-life questions are rarely answered by looking at a date alone.
As a sealing distributor, we can help customers gather and review available information, identify questions that may need clarification, and communicate with relevant manufacturing sources when appropriate.
Depending on the product and circumstances, we may be able to assist with:
- Reviewing available part and material information
- Identifying applicable customer or order requirements
- Clarifying date and packaging information
- Communicating questions to the manufacturer
- Discussing replacement or sourcing options
- Helping address shelf-life requirements earlier in the purchasing process
Performance Seals does not assume responsibility for independently certifying the continued usability of stored seals unless specific inspection, testing, or documentation requirements have been agreed upon in writing.
Final decisions regarding acceptance and use should be based on the applicable specifications, manufacturer guidance, customer requirements, documented storage history, application conditions, and any required engineering or quality approval.
Related Pages
Address Shelf-Life Questions Early
Seal shelf life is not simply a question of whether a part is old.
Material, storage, documentation, specifications, and application risk all play a role.
By discussing shelf-life expectations during the design, quoting, or sourcing process, customers can help reduce uncertainty later and ensure that applicable requirements are clearly communicated before product is purchased or installed.
Have questions about seal shelf life, storage requirements, or older inventory? Contact Performance Seals to discuss the information available and the next steps that may be appropriate for your application.
This article is provided for general educational purposes only. It does not establish a warranty, certification, acceptance decision, shelf-life extension, or determination of fitness for use. Applicable drawings, specifications, purchase orders, manufacturer guidance, customer requirements, and agreed-upon order terms control.