The ALARP principle in process safety

Abstract

The principle that the risks for a facility should be reduced to As Low As Reasonably Practicable (ALARP) increasingly is embraced around the world. This article describes how the principle can be used to establish both individual and group risk tolerance criteria that are needed for risk analysis studies using techniques such as Layers of Protection Analysis. The consideration of uncertainties in risk estimates in the ALARP context and the use of the precautionary principle are also described, and the use of cost-benefit analysis in applying the ALARP principle is discussed. Other related principles used in risk management are described.

Numerical risk tolerance criteria in the United States: A critique of the risk criterion used for the New Jersey Toxic Catastrophe Prevention Act

“…Equity is achieved by classifying risks higher than a limit of tolerability as unacceptable. Moreover, lack of a maximum risk value is inconsistent with the widespread use of the ALARP principle by regulators and companies around the world (CCPS, 2009;Baybutt, 2014a). Thus, the TCPA approach is inconsistent with proven risk management approaches employed for catastrophic accident risk.…”

“…Either require the correct allocation of an overall facility risk tolerance criterion to release scenarios or require the calculation of individual and group risk to people for comparison with facility risk criteria (Baybutt, 2014b). Address uncertainties in the risk assessment results when comparing them with risk tolerance criteria (Baybutt, 2014a).…”

“…Facilities with a total cancer risk between ten in a million (1 Â 10 À5 ) and one hundred in a million (1 Â 10 À4 ) are required to pursue a long-term risk minimization strategy while facilities with a total cancer risk between one hundred in a million (1 Â 10 À4 ) and one thousand in a million (1 Â 10 À3 ) also are required to pursue a short-term risk minimization strategy. Essentially, this is an application of the As Low As Reasonably Practicable (ALARP) Principle (HSE; Baybutt, 2014a).…”

“…Regulatory authorities who use risk criteria for catastrophic accidents employ a de manifestus criterion as the primary reference point, not a de minimis criterion. For example, the United Kingdom Health and Safety Executive (UK HSE) uses a tolerability of risk framework that incorporates the ALARP principle (HSE; Baybutt, 2014a) in which the de manifestus criterion must be met but the de minimis criterion is a goal towards which risk reduction efforts must strive but which may not be attained. Use of the ALARP principle requires that efforts to reduce risk should be continued until the incremental sacrifice is grossly disproportionate to the value of the incremental risk reduction achieved.…”

Managing process risks

“…In contrast, the United Kingdom Health and Safety Executive has created the Tolerability of Risk framework for managing risks in processes []. It incorporates the As Low As Reasonably Practicable principle which is used to set performance targets for facility risk [].…”