Cost Benefit Analysis & ALARP
(As Low As Reasonably Practicable) Services
Demonstrating That Risk is Reduced to ALARP
In regulated industries, reducing risk is not simply about applying additional safeguards. It requires demonstrating that risks have been reduced so far as is reasonably practicable (ALARP).
This involves balancing risk reduction against the time, cost and effort required to achieve it.
For facilities handling hazardous materials or operating under COMAH and DSEAR regulations, ALARP is a central principle in demonstrating that risks are being managed appropriately.
Cost Benefit Analysis (CBA) provides a structured way to support these decisions, particularly where the level of risk reduction and the justification for further measures need to be clearly demonstrated.
What Is Cost Benefit Analysis and ALARP in Process Safety?
Cost Benefit Analysis in process safety is a structured, data-driven method of comparing the monetary value of risk reduction benefits against the costs of implementing additional control measures. ALARP, meaning As Low As Reasonably Practicable, is the principle that risk must be reduced unless the cost of further reduction would be grossly disproportionate to the benefit gained.
Together, they provide a transparent and defensible framework for demonstrating that major accident risks are being managed appropriately.
In high hazard industries, risk cannot always be eliminated entirely. The legal and regulatory expectation across the UK and Europe is that risks are reduced to a level that is tolerable and ALARP.
This requires:
• Systematic identification of major accident hazards
• Evaluation of available risk reduction measures
• Transparent justification of decisions
• Clear communication between technical, commercial and leadership stakeholders
A structured Cost Benefit Analysis reduces bias and improves consistency in decision making, particularly where significant capital expenditure or operational impact is involved.
Cost Benefit Analysis is typically undertaken when:
- HAZOP or LOPA identifies high consequence scenarios
- Additional safeguards are being considered
- Safety Instrumented Functions require justification
- Major capital upgrades are proposed
- Ageing plant requires risk-based renewal decisions
- Preparing or updating COMAH Safety Reports
- Responding to regulatory challenge
It is particularly relevant where multiple risk reduction options exist and prioritisation is required.
A structured approach typically includes:
- Hazard and Scenario Definition: Clear identification of credible major accident scenarios.
- Risk Estimation: Assessment of frequency and consequence using qualitative or semi-quantitative methods.
- Identification of Risk Reduction Options: Engineering, administrative or procedural measures aligned to the hierarchy of control.
- Cost Estimation: Capital, operational and lifecycle costs associated with implementation.
- Benefit Valuation: Estimation of avoided harm, including societal risk reduction where appropriate.
- Gross Disproportion Assessment: Comparison of costs and benefits to determine whether further measures are reasonably practicable.
- Documentation and Communication: Clear reporting suitable for leadership review and regulatory scrutiny.
This structured process supports consistent, defensible decisions.
IDEA has extensive experience supporting clients with hazard identification, risk assessment and ALARP demonstration across complex and regulated sectors in Scotland, the UK and Europe.
Our work spans:
- Chemical manufacturing with reactive, toxic or flammable inventories
- Distilled spirits facilities managing large volumes of flammable liquids
- Food and drink manufacturing with combustible dust and solvent hazards
- Life sciences and pharmaceutical sites with solvent and pressure systems
- Biotechnology facilities involving fermentation and gas handling
- Energy and renewables projects including hydrogen and alternative fuels
In many cases, Cost Benefit Analysis is integrated with HAZID, HAZOP and LOPA studies to ensure that risk reduction decisions are consistent across the process safety lifecycle.
Our experience enables us to align technical rigour with commercial realism, ensuring that recommendations are proportionate and implementable.
A structured approach to ALARP supports:
- Defensible risk reduction decisions
- Clear justification of design and operational choices
- Alignment with regulatory expectations
- Improved confidence during audits and inspections
- Reduced risk of over- or under-engineering
This provides decision-makers with a transparent and auditable basis for managing process safety risk.
Depending on scope, deliverables may include:
- Structured ALARP demonstration reports
- Cost Benefit Analysis documentation
- Gross disproportion assessment summaries
- Risk reduction option comparisons
- Inputs to COMAH Safety Reports
- Leadership briefing summaries
- Regulatory support documentation
Outputs are designed to be clear, auditable and defensible.
Frequently Asked Questions
Quick answers to questions you may have about our services
The gross disproportion test compares the cost of implementing a risk reduction measure against the benefit gained. A measure should be implemented unless the cost is grossly disproportionate to the risk reduction achieved.
Yes. In the UK, duty holders are required to reduce risks to a level that is As Low As Reasonably Practicable under health and safety law and major hazard regulations.
A formal Cost Benefit Analysis is typically required when risk levels are significant, consequences are severe, or where the justification for additional safeguards must be clearly documented for regulatory or leadership review.
The duty holder or asset owner is responsible for demonstrating that risks are ALARP, supported by engineering, safety and commercial functions.
CONTACT US
Talk to our Process Safety Team
If you are considering additional safeguards, capital upgrades or need to demonstrate that risks have been reduced to ALARP, we can review your current position and advise on proportionate, defensible next steps.
Structured Cost Benefit Analysis strengthens both safety and decision confidence.