SIST EN 549:1996

Rubber materials for seals and diaphragms for gas appliances and gas equipment

This standard specifies requirements and associated test methods for vulcanized rubber materials used in gas appliances and equipment in contact with 1st, 2nd and 3rd family combustible gases. It also establishes a classification based on temperature range and hardness. This standard is applicable to materials from which are manufactured homogeneous seals and homogeneous or reinforced diaphragms.  The normal range of operating temperatures covered by this standard is 0 oC to + 60 oC. Tests are also included for applications using diaphragms within the range - 20 oC to + 80 oC and seals within the range - 20 oC to + 150 oC. For temperatures outside these ranges the user should contact the manufacturer regarding the suitability of the rubber material.  This standard includes two normative annexes for the verification that a component (finished product) was produced from a previously type tested material complying with requirements of this standard as declared by the appliance or equipment manufacturer or supplier of the component.  This standard is not applicable to silicone rubber used either above 200 mbar nominal pressure or at temperatures below 0 oC with 3rd family gases as there is possibility of condensation. This standard is also not applicable to seals and diaphragms for devices in gas transmission systems nor in such equipment used in 1st and 2nd family gas distribution systems.