Considerations of ALARP for Complex Safety Related Systems

The introduction of ALARP into Health and Safety legislation has had a profound impact upon the way in which system safety is addressed in the UK. Initially mandated by the HSE, it is now in constant and widespread use across MoD projects. There are a number of MoD standards and publications that mandate the use of ALARP, including Def Stan 00-56, 2004 and JSP 430, 2005 by way of example. A considerable amount of experience and advice has been accrued, yet still issues and problems persist around the application of ALARP, particularly in complex systems. This paper identifies some of the issues surrounding the practical application of ALARP in the tolerable region of the risk diagram, and highlights some of the limitations of the guidance and advice that is already available. The paper explores some of the more fundamental issues and opens up debate to determine whether such issues could be addressed.