scope:

This specification defines the requirements for toroidal sealing rings ('O' rings) manufactured from materials which have been approved to D.T.D.5582 - "Oil Resistant Vulcanized Silicone Rubbers". They may be used in reciprocating mechanisms or for static purposes in contact with heavy mineral and diester based liquids within a temperature range of -60" to + 150°C for continuous operation or 200°C for short intermittent periods.

For application in contact with air they may be considered for use up to 250°C. They are unsuitable contact with petroleum based fuels, light mineral oils or greases derived from these. They have excellent ozone resistance.

Note. At ordinary temperature and in the absence of hostile environments eg. when properly stored, these rubbers deteriorate only very slowly. For most practical purposes the effect is insignificant and the storage life of silicone rubber may be considered indefinite.

However, the rate of deterioration increases markedly with increased temperature and the service life of the rubber therefore depends upon the operational temperature. Conversely, the maximum temperature at which the rubber may be used depends upon the useful life required.