NATIONAL FOREWORD

This Indian Standard (Part 20) (Second Revision) which is identical with ISO 1431-1 : 2012 ‘Rubber, vulcanized or thermoplastic — Resistance to ozone cracking — Part 1: Static and dynamic strain testing’ issued by the International Organization for Standardization (ISO) was adopted by the Bureau of Indian Standards on the recommendation of the Methods of Test for Rubber and Rubber Products Sectional Committee and approval of the Petroleum, Coal and Related Products Division Council.

This standard was originally published in 1977 and subsequently revised in 1994. First revision was based on ISO/R-1431:1972 ‘Vulcanized rubbers — Determination of resistance to ozone cracking under static conditions’ and ASTM D 1149 - 64 ‘Accelerated ozone cracking of vulcanized rubbers’. The second revision of this standard has been undertaken to align it with the latest version of ISO 1431-1 : 2012.

The method prescribed in this standard might not give results correlating exactly with outdoor exposure tests, since correlation of accelerated ozone tests with performance is, in general, not good and is highly dependent upon the specific conditions of both the accelerated and outdoor exposures. Conditions that influence accelerated test are ozone concentration, relaxation of stress, temperature and degree of bloom of additives. Conditions that influence outdoor tests in addition to these are the amount of sunshine and rainfall. The first revision of this standard was taken up as a result of review of the standard in the light of experience gained over the years and the Committee had decided to revise this standard under dual numbering with ISO 1431-1: 1989.

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.