Does ALARP = Due Diligence?
Does ALARP equal due diligence? Well yes, if ALARP (as low as reasonably practicable) is redefined, as appears to be presently occurring.
Once upon a time ALARP meant achieving an acceptable or tolerable level of risk (consequence and likelihood). It was classically articulated by the UK HSE (Health and Safety Executive) in 1988 in the document The Tolerability of Risk from Nuclear Power Stations. The HSE suggested the limit of tolerable risk to a worker is 10-3 per year; the limit of tolerable risk to a member of the public is taken as 10-4 per year. The risk to a member of the public that might be regarded as acceptable, as opposed to tolerable, is then taken as 10-6 per year. Such a concept was then taken up extensively in Australia, for example the NSW land use planning guidelines (2008).
However to satisfy the courts after the event, various caveats have been added to this approach. For example, from the NSW guidelines, … irrespective of numerical risk criteria, the broad aim should be to ‘avoid avoidable risk.’ Another common caveat is to say that, irrespective of the level of risk, the value of further precautions should always be considered.
Effectively this means that ALARP is being redefined to mean the level of risk which is achieved if all reasonable practicable precautions are in place, that is, a demonstration of due diligence. Of course, ALARP remains a hazard based concept. It talks about the level of risk, not the level of precautions, the court based concept. This means ALARP typically remains subject to at least two primary conceptual errors, namely:
- Risk AssessmentRisk assessment is not scientific. Two risk experts independently assessing the risk never come up with the same answer. Risk assessments are not repeatable. So what does a risk assessment mean? How can it be right?
- Risk CriteriaRisk assessments are then normally compared to criteria. But such criteria are generally just statistical interpretations. They are not statements of truth. The old adage, that there are lies, damned lies and then there are statistics applies.
It is a very complex process to chart a course through the hazard based process that can arrive at a due diligence position. It needs at least the two caveats described above to be applied to what is a tortuous, error prone path.