scope:

This Standard applies to all safety related equipment in the gas in industry. It is the industry specific guidance which seeks to fulfil the requirements of the IEC Standard IEC 61508 (BS EN 61508 in the UK).

IGEM/SR/15 was first published in 1989 and the 4th Edition dates from 2005. Safety engineering is a rapidly developing and changing discipline and, indeed, the IEC 61508 Standard has been re-issued (as 2010 edition). Therefore, due to changes in risk targeting and the development of specific company guidance it was necessary to update and restructure IGEM/SR/15 in the light of experience and of current thinking. It also reflects the main changes to IEC 61508 where they are relevant.

Major items of update/change are:

• Risk targets reflecting the severity of the consequences (eg multiple fatality)
• Targeting integrity using quantified (including LOPA) and other methods
• ALARP and gross disproportionality
• Restructuring of the life-cycle guidance to reflect the overlap between hardware and software related features
• Safety Manuals to be offered by vendors of safety related equipment
• Alternatives to safe failure fraction claims
• More emphasis on human error
• More emphasis on functional safety plans and specifications