What is ALARP?

In this article:

1. The concept of ALARP

2. How is the ALARP principle implemented in practice?

3. Benefits and challenges

4. Practical Guidance

5. Conclusion

The concept of ALARP 

The As Low As Reasonably Practicable (ALARP) or As Low As Reasonably Achievable (ALARA) principle is a cornerstone of risk management and is a tool used to support decisions in the risk management process and illustrate risk tolerability. The principle means that a risk should be reduced to a level that is as low as reasonably practicable – meaning that the benefit of reducing the risk is weighed against the cost, time, and effort required to do so. A certain risk should not be acceptable just because it is low, if there are reasonable ways to reduce it further. And on the other hand, it is not required to implement actions that are grossly disproportionate to the risk reduction they provide. 

ALARP is often visualized as in the risk matrix below: 

1. Unacceptable risk (red zone) 

   1. Too high to be allowed. 

   2. Must be reduced regardless of cost. 

2. Tolerable risk if ALARP is achieved (yellow zone) 

   1. Risk can be tolerated if further reduction would require disproportionate effort. 

   2. This is where the ALARP principle applies. 

3. Broadly acceptable risk (green zone) 

   1. So low risk that no further action is required. 

(scroll horizontally to view the full table)

				Likelihood Description (Probability or Frequency)
				1	2	3	4	5
	Severity description			Very unlikely. Not occured in the industry.	Unlikely. Has occurred in industry but is rare.	Possible. Occurs in the industry every year.	Likely. Occurs in the plant every year.	Very likely. Occurs in the plant several times per year.
	Safety	Environment	Asset	10000 years / 10-4 / site	1000 years / 10-3 / site	100 years / 10-2 / site	10 years / 10-1 / site	1 year / site
A	Minor injury / Reversible health effect / Restriction to work activity	Negligible: minor release within fence, easily cleaned.	Negligible damage or loss of < 1% of total assets	1A	2A	3A	4A	5A
B	Lost time injury (1 day) / Medium-term health effect	Minor: noticeable nuisance off site (e.g., discernible odor) / minor breach of permitted emission limits, but no environmental harm / release inside the fence – recoverable.	Minor damage or loss of 1% to 20% of total assets	1B	2B	3B	4B	5B
C	Major injury / Lost time injury (>3 days) / irreversible health effect	Severe: release to sensitive receptor / minor contamination over public area / easily recoverable / single breach to operating license.	Major damage or loss to 20% to 50% of total assets	1C	2C	3C	4C	5C
D	Fatality / Serious disability / Life threatening health effect	Major: serious toxic effect on beneficial or protected species / contamination over public area / extensive remediation / multiple breach to operating license.	Extensive damage or loss of 50% to 75% of total assets	1D	2D	3D	4D	5D
E	Multiple on-site fatalities or single off-site fatality	Catastrophic: serious contamination of groundwater or watercourse with extensive loss of aquatic life / major contamination over large public area / extensive remediation resulting in visible change.	Catastrophic damage or loss of 75% to 100% of total assets	1E	2E	3E	4E	5E

How is the ALARP principle implemented in practice?  

Embedding Risk Appetite into the risk matrix 

Overlaying the risk matrix is the organization’s risk appetite—the level of risk it is willing to accept in pursuit of its objectives. The boundaries of what is considered tolerable, ALARP, or intolerable on the matrix reflect this appetite. 

For example: 

• A company with a conservative risk appetite may set the threshold for ALARP lower, prompting more scenarios to be scrutinized and mitigated. 

• A company operating in a frontier or exploratory environment may accept higher levels of risk, provided it can demonstrate that all reasonably practicable measures have been taken to mitigate those risks. 

• By incorporating risk appetite into the design of the matrix and its application in workshops, organizations ensure that risk ranking outcomes are not only technically sound but also strategically aligned with their corporate values, regulatory obligations, and stakeholder expectations. 

The value of this Integration 

This integrated use of ALARP, risk matrices, and risk appetite during HAZID and HAZOP studies offers several benefits: 

• It ensures that subjective risk judgments are grounded in a consistent framework. 

• It promotes transparent, auditable decisions, especially when justifying why further risk reduction was or was not pursued. 

• It supports a culture of proactive risk ownership, with all stakeholders understanding how risk decisions align with both safety standards and business strategy. 

Ultimately, this approach ensures that risk management is not treated as an isolated technical activity but as an embedded part of operational and strategic decision-making. It allows organizations to make informed, defensible, and balanced decisions in complex, high-risk environments—delivering safety and efficiency while meeting stakeholder and regulatory expectations. 

Benefits and Challenges 

 The ALARP principle brings several benefits to risk management: 

• Encourages proactive safety culture and ownership of risk. 

• Supports regulatory compliance and helps avoid penalties or shutdowns. 

• Improves transparency and accountability in safety-related decisions. 

• Drives innovation by incentivizing cost-effective risk reduction solutions. 

However, there are also challenges: 

• The definition of "reasonably practicable" can be subjective and may vary between jurisdictions. 

• Quantifying costs and benefits for certain safety measures can be difficult, especially where consequences are low-frequency but high-impact. 

• In some organizations, there may be a tendency to use ALARP as a justification for inaction unless it is properly understood and applied. 

Practical Guidance 

To ensure the ALARP principle is applied effectively and consistently, organizations should adopt a structured approach that balances risk reduction with practicality. The following recommendations provide guidance on embedding ALARP into decision-making processes, enhancing transparency, and aligning risk management with both operational and strategic objectives. 

• Develop a strategy for how to manage ALARP scenarios and determine what is ALARP. 

• Embed organizational risk appetite into the risk matrix to ensure ALARP decisions align with strategic objectives. 

• Regularly review and update ALARP thresholds to reflect changes in regulatory requirements, operational conditions, or corporate risk appetite. 

• Use cost-benefit analysis to quantify the effort versus the risk reduction for proposed measures, ensuring actions are reasonably practicable. 

• Encourage a proactive safety culture by assigning clear ownership for ALARP assessments and risk mitigation measures. 

• Integrate ALARP evaluation into HAZID, HAZOP, and other risk assessment workshops to ensure consistency across risk management activities. 

Conclusion 

In summary, ALARP is a powerful tool that, when properly implemented, supports risk management in a structured, transparent, and legally defensible way. Its integration into the use of risk matrices and alignment with corporate risk appetite, ensures that risks are evaluated not just in terms of what is technically feasible but also within the strategic and operational context of the business. 

Do you need any support with developing ALARP strategies for your company or wonder how to implement it for your project? Reach out to ORS and we will guide you in the process.