Revised Standard from Last Update.

NATIONAL FOREWORD

This Indian Standard (Second Revision) which is identical with ISO 4633 : 2015 ‘Rubber seals — Joint rings for water supply, drainage and sewerage pipelines — Specification for materials’ issued by the International Organization for Standardization (ISO) was adopted by the Bureau of Indian Standards after the draft finalized by the Rubber and Rubber Products Sectional Committee had been approved by the Petroleum, Coal and Related Products Division Council.

The vulcanized rubber sealing rings are generally used in joining all kinds of drainage pipe-systems, such as, sewers, sewage pumping mains, soil and waste ventilating rain-water pipes and water mains; where, the pipes are of concrete, vitrified clay, cast iron, steel, plastics, pitch fibre or asbestos cement.

This standard was originally published in 1969 and subsequently revised in 1985. The first revision of this standard was based on ISO 4633 : 1983 ‘Rubber seal — Joint ring for water supply, drainage and sewerage pipelines — Specification for material’.

In the first revision, sealing rings were broadly classified into 2 types, Type 1 — Depending on the nature of the rubber (natural or synthetic or both) and not resistant to oil or solvent; and Type 2 — Synthetic rubber and resistant to oil or solvent. Under each type, 5 sub-types in Type 1, and, 4 sub-types in Type 2, were included based on the differences in the physico-chemical requirements. Further, 6 types of rings were recognized based on nominal hardness values and additional requirements of ageing, cold resistance and splice strength were included. Stress relaxation in compression after 7 and 90 days was also included. Measurement of hardness, tensile strength and elongation, at break and volume change prescribed for Type 2 rings, after oil immersion at 100°C for 72 h, existing in the original standard, was excluded. However, minimum requirements for tensile strength and elongation at break were specified for all 6 types depending on the polymer used for the manufacture of rings.

The second revision of this standard has been undertaken to align it with latest version ISO 4633 : 2015.

The major changes in this revision are as follows:

a) Temperature of application has been mentioned in scope;

b) Nominal IRHD has been modified for type 6;

c) Requirement for microbiological deterioration has been included;

d) Requirements of water immersion and splice strength test have been modified;

e) Separate requirements of tensile test, elongation for NR, SBR, and EPM have been merged in to one;

f) Low temperature compression set test and ozone resistance test have been added;

g) Requirement for volume change in oil has been added as optional requirement;

h) Requirement for sampling and criteria for conformity has been removed; and

j) Requirement for microbiological deterioration as given in 4.1.3 shall be as agreed between manufacturers and purchaser.

The text of ISO Standard has been approved as suitable for publication as an Indian Standard without deviations. Certain terminologies and conventions are, however, not identical to those used in Indian Standards. Attention is particularly drawn to the following:

a) Wherever the words ‘International Standard’ appear referring to this standard, they should be read as ‘Indian Standard’.

b) Comma (,) has been used as a decimal marker, while in Indian Standards, the current practice is to use a point (.) as the decimal marker.