Revised Standard from Last Update.

NATIONAL FOREWORD

This Indian Standard (Part 3) (First Revision) which is identical with IEC 61508-3 : 2010 ‘Functional safety of electrical/electronic/programmable electronic safety-related systems — Part 3: Software requirements’ issued by the International Electrotechnical Commission (IEC) was adopted by the Bureau of Indian Standards on recommendation of the Industrial Process Measurement and Control Sectional Committee and approval of the Electrotechnical Division Council.

This standard was originally published in 2008 and was identical with IEC 61508-3 : 1998. The first revision of this standard has been undertaken to align it with the latest version of IEC 61508-3 : 2010.

This Indian Standard supersedes the IS/IEC 61508-3 : 1998.

The major changes in this revision are as follows:

a) Introduction of the idea of desirable Properties (such as completeness, correctness and predictability) for the output of each lifecycle phase.

b) Provision of extended requirement for the selection and justification of software development tools.

c) Allowing software elements which were not originally developed with safety in mind to be re-used in safety related applications by the provision of suitable evidence including evidence of successful use in other applications.

d) Revision to the set of technique and measures in Annexes A and B, to remove obsolete or littleused techniques and introduce current methods.

The text of IEC 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.