ALARP / Cost-Benefit Analysis Tool

HSE SPC · Permissioning · Document 37 · VPF Methodology

Rev.0

HUMAIN Engineering — ALARP / Cost-Benefit Analysis Tool

Aligned with HSE R2P2 & SPC/Permissioning/37 | Generated:

Receptor Type
Workers
Public
Max tolerable risk: 1×10⁻³ p.a.  |  Broadly acceptable: 1×10⁻⁶ p.a.
Scenario Parameters
Mitigated scenario frequency from LOPA output
Individual risk target after proposed measure
⚠ IR reduced must be less than IR current and greater than zero.
Effective life of proposed measure (typically 25 yrs for new plant)
Proposal Cost
Design, procurement and installation — one-off
Annual maintenance and inspection cost
Total cost = CAPEX + (OPEX × years) £ 100,000
Savings and lost production are conservatively set to zero — consistent with HSE guidance.
Value of Preventing a Fatality (VPF)
HSE CBA document — fatality value
BoE average — 3.0% p.a. per HSE CBA document basis
Inflation-adjusted VPF (2026) £ 2,546,482
Tolerability Assessment
IR current compared against HSE R2P2 individual risk criteria:
ALARP region — CBA recommended
Risk lies between the broadly acceptable limit (1×10⁻⁶ p.a.) and the maximum tolerable limit. ALARP must be demonstrated. Cost-benefit analysis is recommended to support that demonstration.
1 Safety Benefit
This measure reduces individual risk by — p.a., preventing — statistical lives over — years.
—
Monetised safety benefit
2 Maximum Justified Spend
Gross Disproportionality Factor (GDF) = — — reflecting the proximity of IR current to the intolerable limit.
—
Maximum justifiable investment
3 Proposal vs Threshold
Proportion Factor (PF) = Cost ÷ Benefit = —  |  GDF threshold = —
PF = 0 GDF PF = GDF × 2
Total proposal cost
—
Max justified spend
—
✅
Measure is justified — adopt it
Enter parameters to generate results.
Disclaimer
This tool provides indicative results aligned with HSE guidance on ALARP and Cost-Benefit Analysis. It does not constitute formal engineering advice. Users are responsible for verifying inputs and outputs against applicable standards and site-specific requirements.

Contact: [email protected]   |   www.humainengineering.com
Aligned with HSE guidance on ALARP and Cost-Benefit Analysis.