ISO 9631:2018 specifies material requirements for vulcanized rubber seals for hot drinking and non-drinking water supply (up to 110 °C).

The different seal designations specified are defined according to seal type, seal application and the requirements for a particular seal (see Table 2).

General requirements for finished joint seals are also given. Any additional requirements called for by the particular application are specified in the relevant product standards, taking into account that the performance of pipe joints is a function of the seal material properties, seal geometry and pipe joint design. This document is intended to be used where appropriate, in conjunction with product standards which specify performance requirements for joints.

ISO 9631:2018 is applicable to joint seals for use with all pipeline materials, including metals, clay, fibre cement, concrete, reinforced concrete, plastics and glass-reinforced plastics.

ISO 9631:2018 is applicable to elastomeric components of composite and non-composite seals. In the case of composite seals made from materials with hardness ranging from 76 IRHD to 95 IRHD, the requirements for elongation at break, compression set and stress relaxation apply only when the material participates in the sealing function or contributes to the long-term stability of the seal.

The material requirements specified in this document are designed for long term performances and a potential lifetime of 50 years. The lifetime of a sealing depends not only on material performance but also on other parameters which are not defined in this document like the mounting design, the quality of assembly and the combination with operating conditions. Joint rings made from cellular rubber materials are not covered by this document.