There can be seen some changes on rubber elements which are sotraged at unsuitable conditions for a long time. The factors like oxygen volume, sun light (direct or reflected), humidity, UV lights, heat and dust-dirt at the storage place have effects on these changes. When required precautions are taken and conditions are created, lifetime of rubber parts can be much longer as well as they can keep their properties longer too.
Temperature
The storage temperature should be between +5ºC and +25ºC. Direct contact with sources of heat such as boilers, radiators and direct sunlight should be avoided.
Humidity
The relative humidity in the store room should be below 70%. Very moist or very dry conditions should be avoided. Condensation should not occur at the area.
Light
Elastomeric seals should be protected from light sources, in particular direct sunlight or strong artificial light with an ultraviolet content. It is advisable to cover any windows of storage rooms with a red or orange coating.
Oxygen and Ozone
As ozone is particular deleterious to some elastomeric seals, storage rooms should not contain any equipment that is capable of generating ozone, such as high voltage electrical equipment, electric motors or other equipment whichmay give rise to electric sparks or silent electrical discharges.
Rubber sealing elements must be packaged with air-proof polyethylene (PE) material to avoid from the destruction of oxygene.
Deformation
Elastomeric materials should be stored in a relaxed condition free from tension, compression or other deformation
Contact with metals
Direct contact with certain metals, e.g. manganese, iron and particularly copper and its alloys, e.g. brass and compounds of these materials are known to have deleterious effects on some rubbers. Elastomeric seals should not be stored in contact with such metals.
When stored under the recommenden conditions the below given shelf life of several materials’ life can be longer. The terms for some elastomeric materials are;
- NBR, HNBR, CR 6 years
- EPDM 8 years
- FKM, VMQ, FVMQ 10 years
- PTFE unlimited