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.