IMechE “ALARP for Engineers” – A Technical Safety Guide
This Institution of Mechanical Engineers (IMechE) guide provides practical engineering guidance on applying the principle of reducing risks to As Low As Reasonably Practicable (ALARP).
The report explains how engineers and duty holders can demonstrate that safety risks have been reduced appropriately while balancing the costs, benefits and effectiveness of additional control measures. It provides a structured framework for developing defensible safety arguments and making proportionate risk-reduction decisions.
Key topics include:
- Understanding the ALARP principle
- Gross disproportion and cost-benefit considerations
- Risk reduction decision-making
- Developing well-reasoned safety arguments
- Proportionality in safety assessments
- Demonstrating compliance with legal duties
- Safety case development
- Engineering judgement and governance
This resource is relevant to:
- LEV Designers
- Commissioning Engineers
- P601 Thorough Examination & Test Engineers
- Occupational Hygienists
- Health & Safety Professionals
- Duty Holders
- Facilities Managers
- Process Engineers
- Safety Engineers
- Risk Managers
Source Document
Source: IMechE
Document Type: Technical Safety Guide
Status: Current
Last reviewed by LEVCentral: June 2026
LEVCentral Expert Commentary
Although not specifically an LEV publication, this guide addresses a principle that underpins almost every significant engineering control decision.
Many organisations can demonstrate compliance with recognised standards, but fewer can clearly explain why a particular control strategy was selected, why alternative options were rejected and how they determined that risks had been reduced sufficiently.
The ALARP principle provides a structured framework for making and defending these decisions, sensitising agents or major accident hazards may require significantly deeper assessment.
