As low as reasonably practicable (ALARP), or as low as reasonably achievable (ALARA), is a principle in the regulation and management of
safety-critical
A safety-critical system or life-critical system is a system whose failure or malfunction may result in one (or more) of the following outcomes:
* death or serious injury to people
* loss or severe damage to equipment/property
* environmental h ...
and
safety-involved systems.
The principle is that the
residual risk The residual risk is the amount of risk or danger associated with an action or event remaining after natural or inherent risks have been reduced by risk controls.
The general formula to calculate residual risk is
: \text = (\text) - (\text)
wher ...
shall be reduced as far as reasonably practicable. In UK and NZ
Health and safety law
Occupational safety and health (OSH) or occupational health and safety (OHS) is a multidisciplinary field concerned with the safety, health, and welfare of people at work (i.e., while performing duties required by one's occupation). OSH is re ...
, it is equivalent to so far as is reasonably practicable (SFAIRP). In the US, ALARA is used in the regulation of radiation risks.
For a
risk
In simple terms, risk is the possibility of something bad happening. Risk involves uncertainty about the effects/implications of an activity with respect to something that humans value (such as health, well-being, wealth, property or the environ ...
to be ALARP, it must be possible to demonstrate that the cost involved in reducing the risk further would be disproportionate to the benefit gained.
Factors
Determining that a risk has been reduced to ALARP involves an assessment of the risk and costs involved in taking measures to avoid that risk, and a comparison of the two according to
cost–benefit analysis
Cost–benefit analysis (CBA), sometimes also called benefit–cost analysis, is a systematic approach to estimating the strengths and weaknesses of alternatives. It is used to determine options which provide the best approach to achieving benefits ...
(CBA). In this context, risk is the combination of the frequency (likelihood) and the consequence of a specified hazardous event. Several factors are likely to be considered when deciding whether or not a risk has been reduced as far as reasonably practicable:
* Health and safety guidelines and codes of practice
* Manufacturer's specifications and recommendations
* Industry practice
* International standards and laws
* Suggestions from advisory bodies
* Comparison with similar hazardous events in other industries
* Cost of further measures would be disproportionate to the risk reduction benefits they would achieve
* Cost of assessing the improvement gained in an attempted risk reduction. In extremely complex systems, this can be very high, and could be the limiting factor in practicability.
A difficulty arising in CBAs is assigning a meaningful and agreed financial
value of life
The value of life is an economic value used to quantify the benefit of avoiding a fatality. It is also referred to as the cost of life, value of preventing a fatality (VPF), implied cost of averting a fatality (ICAF), and value of a statistical l ...
. In the context of ALARP, financial values to impacts to the environment, physical assets, production stoppage, company reputation, etc. are assigned, which also presents significant challenges to the analysis.
Carrot diagrams

'Carrot diagrams' show high (normally unacceptable) risks at the upper/wider end and low (broadly acceptable) risks at the lower/narrower end, with a 'tolerable' or 'ALARP' region in between. They were originally developed by the
Health and Safety Executive
The Health and Safety Executive (HSE) is a British public body responsible for the encouragement, regulation and enforcement of workplace health, safety and welfare. It has additionally adopted a research role into occupational risks in Great B ...
(HSE) to illustrate their framework for the Tolerability of Risk (TOR), which set out the HSE's approach to regulating safety risks. While the ALARP principle applies at all levels of risk under UK health and safety law, the TOR framework captures the concept that some risks are too great to be acceptable, whatever the benefit; while others are so low as to be insignificant. The HSE, as regulators, would not usually require further action to reduce these broadly acceptable risks unless reasonably practicable measures were available, although they would still take into account that duty holders must reduce risks wherever it is reasonably practicable to do so. Between the two extremes, risks can be tolerated in order to secure benefits, so long as they have been risk assessed and are kept ALARP.
Carrot diagrams are sometimes known as 'ALARP Triangles'. However, this can be misleading because they illustrate the Tolerability of Risk framework rather than the ALARP principle itself, and can be misinterpreted as meaning either that ALARP legally applies only in the tolerable region, or that risks in tolerable region are automatically ALARP.
Origin in UK
The term ALARP arises from UK legislation, particularly the
Health and Safety at Work etc. Act 1974, which requires "Provision and maintenance of plant and systems of work that are, so far as is reasonably practicable, safe and without risks to health". The phrase So Far As is Reasonably Practicable (SFARP) in this and similar clauses is interpreted as leading to a requirement that risks must be reduced to a level that is As Low As is Reasonably Practicable (ALARP).
The key question in determining whether a risk is ALARP is the definition of
reasonably practicable. This term has been enshrined in the UK
case law
Case law, also used interchangeably with common law, is a law that is based on precedents, that is the judicial decisions from previous cases, rather than law based on constitutions, statutes, or regulations. Case law uses the detailed facts of ...
since the case of ''
Edwards v. National Coal Board'' in 1949. The ruling was that the risk must be significant in relation to the sacrifice (in terms of money, time or trouble) required to avert it: risks must be averted unless there is a gross disproportion between the costs and benefits of doing so.
Including gross disproportion means that an ALARP judgement in the UK is not a simple cost benefit analysis, but is weighted to favour carrying out the safety improvement. However, there is no broad consensus on the precise factor that would be appropriate: the
HSE recommends that the bias towards safety "has to be argued in the light of all the circumstances applying to the case and the precautionary approach that these circumstances warrant".
The ALARP or ALARA principle is mandated by particular legislation in some countries outside the UK, including Australia, the Netherlands and Norway. Where the ALARP principle is used, it may not have the same implications as in the UK, as "reasonably practicable" may be interpreted according to the local culture, without introducing the concept of gross disproportionality.
In USA
The term ALARA, or "as low as reasonably achievable" is used interchangeably in the United States of America. It is used in the field of
radiation protection
Radiation protection, also known as radiological protection, is defined by the International Atomic Energy Agency (IAEA) as "The protection of people from harmful effects of exposure to ionizing radiation, and the means for achieving this". Exposu ...
.
Its application in the regulation of radiation risk in some areas has been challenged.
In Canada
Health Canada
Health Canada (HC; )Health Canada is the applied title under the Federal Identity Program; the legal title is Department of Health (). is the Structure of the Canadian federal government#Departments, with subsidiary units, department of the Gove ...
's Medical Devices Directorate is transitioning from the ALARP standard to AFAP ("As Far As Possible") in the regulation of risk of medical devices.
The ALARP concept can be interpreted to promote financial consideration in higher regard than of the requirements of safety and performance of medical devices. Contradicting this approach, AFAP requires that all ventures of safety must be addressed in the intent of the consumer and effectiveness of the product rather than capital gain of the corporation. Risks previously deemed 'negligible' may be ignored under the old standard but must be taken into account and included in risk analysis under the newer AFAP-based standard. Under AFAP standards there are two defined justifications for the lack of implementation of risk-preventative measures. The first indicates that the additional risk control will not provide additional support for the system, such as an additional alarm when a previous alarm is functioning. The second states that a risk control system does not have to be implemented if there is a more effective risk control that can not be simultaneously executed due to various scenarios such as spatial boundaries. By implementing this new standard of risk mitigation, companies must demonstrate that they have considered and implemented all necessary means of addressing risk of a product or developed system.
In Australia
In Australia the Work Health & Safety Act 2011 introduced the term So Far As Is Reasonably Practical (SFAIRP) based on the UK legislation. In some industry sectors the term SFARIP has become the common usage and can be used interchangeably with ALARP, but some people believe that SFAIRP and ALARP are two different legal tests.
Legal
A two-year legal battle in the
European Court of Justice
The European Court of Justice (ECJ), officially the Court of Justice (), is the supreme court of the European Union in matters of European Union law. As a part of the Court of Justice of the European Union, it is tasked with interpreting ...
resulted in the SFAIRP principle being upheld on 18 January 2007.
The
European Commission
The European Commission (EC) is the primary Executive (government), executive arm of the European Union (EU). It operates as a cabinet government, with a number of European Commissioner, members of the Commission (directorial system, informall ...
had claimed that the SFAIRP wording in the
Health & Safety at Work Act did not fully implement the requirements of the
Framework Directive. The Directive gives employers an absolute duty "to ensure the safety and health of workers in every aspect related to the work", whereas the Act qualifies the duty "So Far As is Reasonably Practicable". The court dismissed the action and ordered the commission to pay the UK's costs.
[, ]Press release
by the UK Health and Safety Executive
The Health and Safety Executive (HSE) is a British public body responsible for the encouragement, regulation and enforcement of workplace health, safety and welfare. It has additionally adopted a research role into occupational risks in Great B ...
Had the case been upheld, it would have called into question the proportionate approach to safety risk management embodied in the ALARP principle.
See also
* Bureaucratic drift Bureaucratic drift in American political science is a theory that seeks to explain the tendency for bureaucratic agencies to create policy that deviates from the original mandate. The difference between a bureaucracy's enactment of a law and the l ...
* Conflict of interest
A conflict of interest (COI) is a situation in which a person or organization is involved in multiple wikt:interest#Noun, interests, financial or otherwise, and serving one interest could involve working against another. Typically, this relates t ...
* Principal–agent problem
The principal–agent problem refers to the conflict in interests and priorities that arises when one person or entity (the " agent") takes actions on behalf of another person or entity (the " principal"). The problem worsens when there is a gr ...
* Ratchet effect
The ratchet effect is a concept in sociology and economics illustrating the difficulty with reversing a course of action once a specific thing has occurred, analogous with the mechanical ratchet (device), ratchet that allows movement in one dire ...
* Safety integrity level
References
External links
UK Health and Safety Executive ALARP Suite of Guidance
* ttps://web.archive.org/web/20081030035624/http://www.dstan.mod.uk/data/00/056/01000400.pdf UK Defence Standard 00-56 Safety Management Requirements
{{DEFAULTSORT:Alarp
Safety
Process safety
Risk management