It may seem a surprising topic of conversation, but when it comes to o rings and seals, it’s important to note that they do have a shelf life, which, if not monitored and regularly checked, can affect their quality and overall performance.
How and where you store your o rings can and will impact their lifespan, making it important to know the recommended industry recommendations for storage and the shelf life of various o ring materials.
O ring suppliers UK will provide full manufacture guidance and details relating to storage and o ring material type.
Typically you will find:
|O ring material||Shelf Life|
|Certain types of polyurethane||5-10 years|
|NBR, Buna-N, HNBR, chloroprene||15 years|
|FKM, FFKM, silicone, fluorosilicone||Unlimited|
Calculating elastomer and o ring expiry dates
There is no exact science to managing elastomers and the shelf life of o rings. However, working with the manufacturer’s specifications and recommendations is key, and understanding the impact storage and handling can have on rubber o rings is vital.
Often an o ring shelf life is defined based on a customer’s own experience and judgement of their storage, handling, and usage conditions.
The environment where o rings are stored should not be underestimated, nor should the packaging and stock rotation systems we have in place to ensure continued high performance and quality.
O ring storage
As a general rule of thumb, o rings and seals should be stored without hanging (to avoid stretching and tension). They should be kept free from deformation or compression. The environment should be dry, and you must avoid direct sunlight, UV rays, and any artificial light.
SAE – ARP5316 is the recommended elastomer guide for recording procedures, packaging, and storing of aerospace elastomer seals. It is the most comprehensive basis for establishing shelf life (however, we must point out it is not binding, but rather seen as a high industry standard). This guidance document helps provide seal manufacturers, distributors, and users with a foundation to generate realistic shelf life criteria.
In this comprehensive guide, you will find recommendations on:
Temperature – elastomers should be stored at temperatures below 38 degrees Celsius and away from direct heat and sunlight sources.
Humidity – the area should be free from condensation, or elastomers should be stored in moisture-proof bags.
Light – elastomers must avoid direct sunlight, UV, and artificial lights.
Radiation – it’s important that you remove any sources that could cause potential damage to the elastomers stored.
Ozone – you should avoid storing elastomers in the same area as equipment such as Mercury Vapour Lamps or any high voltage electrical equipment. You should also avoid storing elastomers close to combustion gases and organic vapours.
Deformation – avoid areas where compressive stresses occur, and ensure o rings can be stored in their original packaging. Individual packing of seals also helps to maintain traceability, which forms a large part of the production process.
Cure date – we recommend that customers refer to and be aware of `time of manufacture` as part of their stock rotation.
Avoid contact with liquid and semi-solid materials – materials such as greases, gasoline, acids, disinfectants, cleaning fluids, etc.
Avoid certain materials as these can have a negative effect on elastomers.
Dusting powders should be avoided to prevent any sticking or blocking.
Avoid contact with different elastomers and various seals.
Bonded seals should be individually packaged and, ideally, should not come into contact with another seal.
We would always recommend that seals are used on a rotation basis, with the oldest stock used first.
O ring shelf-life – storage guidance for rubber o rings
ISO 2230: Rubber Products can provide additional guidance for o ring storage and life expectancy.
Some main differences between the ISO 2230 and the SAE: ARP5361 include:
Temperature – rubber o rings should be stored at temperatures below 25 degrees Celsius and again away from direct heat sources.
If the storage temperature is below 15 degrees Celsius, it’s important to be aware that the elastomer can stiffen, so it must be handled with extreme care.
When it comes to humidity, this should be less than 75% (however, for polyurethanes, humidity must be less than 65%).
Visual inspections should be regularly carried out, as well as testing to ensure that performance remains within the acceptable limits.
Ultimately, how your o rings are stored can affect their shelf life by approximately 50%, so these areas must be suitable for the elastomers in question.
O ring suppliers Leeds
Specialist Sealing Products are sealing and o ring specialists. Providing customers with a vast range of choices and solutions when it comes to unique and standard seals.
Read the next article: O ring squeeze