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Material Storage Guidelines

A question often asked is ‘how long can I store material for?’ We have asked our Members, who are some of the leading manufacturers and suppliers in the UK, who recommend the following storage guidelines, subject to the material type and guidance published in BS3574:1989 and BS ISO 2230:2002.

If you have any queries regarding storage of materials, please contact one of our Members.


Depending on the material in question, the material may need sealing or wrapping to prevent exposure to strong odours, light and heat and stored in a cool, dry environment. Detailed below are suggested suitable packaging for different materials.

Cellulose Paper: material in roll form should be stored in its polythene bag; cut gaskets should be kept in moisture-proof wrapping or packaging to ensure it does not dry out or absorb too much atmospheric moisture.

Felt: Wool felt should be stored off floor level preferably in sealed bags to prevent moisture ingress. Polyester felts are wholly unaffected in storage but will attract dust and contaminants which can be brushed or vacuumed from the surface.

Rubber: polyethylene, aluminium foil, cardboard and polyethylene laminate.

For further advice, please contact one of our Members.


A number of conditions will affect the storage of materials. These conditions include temperature, ozone, humidity, light, fluids, dusting powders, contact with other products, etc. Care should be taken to select the most appropriate conditions for the material in question.

Cellulose Paper:

  • The gasket material should be stored and cut under reasonably-controlled environmental conditions.
  • Temperature: 10-20 oC
  • Humidity: relative humidity of 50-65%
  • Storage: material in roll form should be stored in its polythene bag; cut gaskets should be kept in moisture-proof wrapping or packaging. This will ensure the product does not dry out or absorb too much atmospheric moisture.


  • Felt should be stored in a dry environment away from air conditioning units or heat sources.
  • Temperature: Optimal storage temperature 5-30oC.
  • Humidity: relative humidity of 40-60%
  • Storage: Wool felt should be packed in sealed polyethene bags until required. Cut wool felt components should be stored in sealed moisture proof packaging.
  • If felt rolls are stored horizontally on racks some flattening at the base may occur overtime, but will not affect the product use. If stored vertically on their ends the roll may spread at the base slightly but again this will not adversely affect the product use.


  • Light – avoid exposure to direct sunlight.
  • Temperature: cool, dry environment.
  • Humidity: extremes of humidity should be avoided.
  • Storage: laid flat in a horizontal position and not rolled. Dust covers recommended when storing sheet gasket materials.
  • Avoid storing in vicinity of high voltage.


  • Temperature – between 15-25oC; away from direct heat sources.
  • Light – avoid exposure to direct sunlight, artificial light or UV light.
  • Humidity – less than 65% to avoid condensation build-up.
  • Fluids – avoid exposure to liquid or semi-liquid materials. If materials are received coated they should be stored in this condition.
  • Dusting powder – should only be used minimally to prevent blocking.
  • Chemical media – avoid exposure to liquids or vapour.
  • Deformation – tension, bending and twisting of material should be avoided.
  • Proofed fabrics or rubber sheeting – material less then 1m2 in area or 2m in length should be stored flat with layers interleaved with suitable material. Longer lengths and larger areas ca be stored rolled with layers interleaved with suitable material.

For further advice, please contact one of our Members.


To check if the material can be stored for longer than the initial storage period, inspection of the material is required. This includes a visual inspection of a sample of material for changes such as distortion, stress, creasing damage, surface degradation, cracks and major colour changes. If any changes are found it is recommended that the material is disposed of or a record maintained detailing the changes to stock.

In addition to a visual inspection, testing of material samples should be undertaken to check performance integrity has been maintained following the initial period of storage. If the material meets visual inspection and tests, storage may be extended further.

Cellulose Paper: Initial storage: 5 years.

Felt: Felt can be stored indefinitely in the correct conditions. However periodic inspections should be maintained if the storage facility has high humidity or there has been potential water ingress near to the stock. The main effect of water absorption will be:

  1. Increase in the set thickness of the material
  2. Potential mildew forming on the felt

If either scenario is found then the felt should be withdrawn from stock and disposed of to prevent cross contamination to other wool based products, especially if mildew is found.


  • Synthetic Fibre Sheet: 3 years
  • Reinforced Graphite Sheet: >5 years
  • Sigma® & Uniflon grades (PTFE): >5 years
  • Thermiculite® (Vermiculite): 3 years


  • Group A: NR/IR/BR/SBR/AU,EU: Initial storage: 5 years. Extended storage: 2 years
  • Group B: ACM/ECO/CR/HNBR/IIR/NBR: Initial storage: 7 years. Extended storage: 3 years
  • Group C/X: CSM/EPDM/FKM/FEPM/FFKM/VMQ/PMQ/PVMQ/FVMQ: Initial storage: 10 years. Extended storage: 5 years

For further advice, please contact one of our Members.