The Definition of ALARP (As Low As Reasonably Practicable)

Definition of ALARP (As Low As Reasonably Practicable)

ALARP stands for "As Low As Reasonably Practicable," a risk management principle that requires risks to be reduced until the time, cost and effort of any further reduction would be grossly disproportionate to the safety benefit gained. ALARP underpins UK health and safety law, where the Health and Safety at Work etc. Act 1974 requires employers to control risks "so far as is reasonably practicable," and similar duties appear in Australian work health and safety laws and in safety case regimes for offshore oil and gas, rail and major hazard facilities. The test comes from the 1949 UK case Edwards v National Coal Board.

Key Facts About ALARP

• The burden is on the duty holder to show that further risk reduction is not reasonably practicable.
• Cost can only justify stopping when it is grossly disproportionate to the benefit, not merely higher than the benefit.
• The UK HSE's tolerability of risk framework sorts risk into unacceptable, tolerable if ALARP, and broadly acceptable regions.
• Following recognized good practice is usually the starting point for demonstrating ALARP.

ALARP vs. ALARA

ALARP and ALARA express nearly the same idea. ALARA, "As Low As Reasonably Achievable," is the term used in radiation protection, including U.S. Nuclear Regulatory Commission rules, while ALARP is used for general workplace and process safety risk, especially in UK, Australian and offshore regimes.

Example of ALARP

An offshore operator reviewing its safety case considers adding a second gas detection array in a compressor module. The cost is modest compared with the reduction in fire and explosion risk to the crew, so the operator installs it. A proposal to relocate the entire module, by contrast, would cost far more than the small additional benefit, and the operator documents why that option is not reasonably practicable.

How to Demonstrate ALARP

1. Identify hazards and assess risk using a qualitative or quantitative risk assessment.
2. Compare existing controls with recognized good practice and standards.
3. Work through the hierarchy of controls to identify further options.
4. For higher risks, weigh the cost of each option against the risk reduction it delivers.
5. Document decisions and revisit them when new technology, incidents or changes occur.

Related Terms

• ALARA
• Hierarchy of Controls
• Duty of Care
• Management of Change (MOC)

Frequently Asked Questions: ALARP

Does ALARP apply in the United States?

ALARP is not a named legal standard under U.S. OSHA, which relies on specific standards and the General Duty Clause's requirement to address recognized hazards with feasible controls. Many U.S. companies in oil and gas, chemicals and other process industries still use ALARP internally and on international operations.

Can cost alone justify not reducing a risk?

Only when the cost is grossly disproportionate to the safety benefit. The more serious the risk, the greater the cost an organization is expected to accept before it can claim further reduction isn't reasonably practicable.

Is there a numerical threshold for ALARP?

Some regulators publish indicative risk criteria, such as individual fatality risk levels that mark unacceptable and broadly acceptable risk, but ALARP itself is a judgment that must be justified for each situation rather than a single number.