This Def Stan specifies requirements for two grades of general purpose rubber sheet, cellular, closed cell, non-(oil resistant) quality, available in various thicknesses for use as cushioning materials as follows:

• Grade 1 medium density;

• Grade 2 high density, for use when a higher load carrying capacity is required.

The material has low water retention properties and is therefore suitable for use outside a water vapour barrier.

The material is not resistant to mineral lubricating oils and petroleum fuels. It is susceptible to mould and fungal growth in warm moist conditions.

If stored for long periods at temperatures below approximately 5°C crystallisation may occur giving rise to stiffening of the material. This effect is most rapid in the region of –25°C. A sufficient rise in storage temperature reverses this effect.

The materials specified in this Def Stan have no requirement for fire retardancy and the materials may burn readily.