The UK Health and Safety Executive (HSE) recently commissioned research from Adelard into how pre-existing software components may be safely used in safety-related programmable electronic systems in a way that complies with the IEC 61508 standard. Two reports resulted from this work and are now published on the HSE web site:

The first report summarises the evidence that is likely to be available in practice relating to a software component to assist in assessing the safety integrity of a safety function that depends on that component.

The second report considers how the available evidence can best be used within the framework of the IEC 61508 safety lifecycle to support an argument for the safety integrity achieved by a safety function.

Whilst these reports are the opinions of the authors alone and do not necessarily reflect HSE policy, HSE offers this work as an illustration of a principled approach to:

  1. gathering evidence on the performance of pre-existing software components;
  2. applying that evidence within the IEC 61508 framework; and
  3. constructing a systematic and transparent argument for the safety integrity of a specified safety function.

HSE proposes to issue guidance on good practice in the use of software components in safety-related systems. HSE invites comments on the practicality and effectiveness of the recommended approach to achieving the above three goals, and on any other significant aspect of the safety integrity of software components that is not addressed by this work.

Please send your comments to:

Dr E Fergus:
Technology Division
Electrical and Control Systems
Magdalen House
Stanley Precinct
Mersey side
L20 3QZ