20 Dec What is ALARP?
What does the ‘ALARP Principle’ mean to you? To some people it means “scary approach to safety involving complicated analysis and open-ended safety obligations”. If that is you (or you have never heard the term) this short article aims to de-mystify ALARP.
ALARP stands for ‘As Low As Reasonably Practicable’ and is the method used, under English Law, to demonstrate that risks have been reduced ‘So Far As Is Reasonably Practicable’. The word ‘reasonably’ is critical! Risks do not need to be reduced as low as practicable – since this could involve enormous cost and trouble to achieve a tiny safety benefit. The trick to ALARP is understanding how you can decide whether additional safety measures would be ‘reasonable’.
A spectrum of solutions
Complying with standards and good practice is often a good way of demonstrating that risks are ALARP. Similarly, ‘Reference Systems’ (i.e. similar applications of the system at another location) can be used to help demonstrate that a system will perform safely. The concept is nicely illustrated in the diagram (taken from RSSB’s publication ‘Taking Safe Decisions’). More routine decisions, on the right of the diagram, are likely to be based on laws, standards, codes and procedures. As the issue becomes more complex, other approaches (e.g. good practice and quantitative analysis, informed by commercial considerations and ethical principles) need to be used.
Whichever approach is used, it is vital that better ways of managing safety are considered – particularly in high risk areas or where the system (or its application) is novel in some way. If you can think of a better way to manage the risk, you then need to decide whether it is reasonably practicable – if it isn’t there is no obligation to implement it. But how do you decide? For the answer, see my Blogs on:
- The role of risk matrices, Cost Benefit Analysis (CBA) and Safety Integrity Levels (SILs)
- Where ‘Tolerability of Risk’ fits in.
For more information I recommend RSSB’s publication: “Taking Safe Decisions” which is available on the RSSB’s website.