This International Standard specifies requirements for materials used in vulcanized-rubber seals for hot potable and non-potable 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 3). 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 International Standard is intended to be used where appropriate with product standards which specify performance requirements for joints. This International Standard is applicable to joint seals for use with all pipeline materials, including iron, steel, clay, fibre cement, concrete, reinforced concrete, plastics and glass-reinforced plastics. It is applicable to elastomeric components of composite and non-composite seals. In the case of composite seals made from materials with hardnesses 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. Joint rings made from cellular rubber materials or with enclosed voids as part of their design are not covered by this International Standard.