scope:

This specification defines the requirements for toroidal sealing rings ('O' rings) manufactured from materials which have been approved to DTD 5583 - "Vulcanized Fluorosilicone Rubbers". They may be considered for long periods of use in applications with petroleum based fuels, hydraulic liquids and lubricants, and with silicone and certain ester based liquids ( but excluding certain phosphate esters) within the temperature range -60° C to 150° C.

The are also suitable for use in air within the temperature range -60° C to 180° C for long periods and up to 200° C for intermittent periods.

The are generally not satisfactory for dynamic applications.

NOTE. At ordinary temperatures 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 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.