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Principles of prevention and hierarchy of controls

The legal basis for the hierarchy of controls in UK health and safety law. Explains the 9 general principles of prevention from Schedule 1 of MHSWR 1999 and the practical ERICPD framework for controlling workplace risks.

Guide summary

You must control workplace risks in a priority order, from most effective to least effective. Start by removing hazards completely if you can. Use personal protective equipment only as a last resort.

  • Remove the hazard completely if possible (Eliminate)
  • Use something less dangerous if you cannot remove the risk (Reduce)
  • Separate people from the hazard using barriers or guards (Isolate)
  • Use training and safe working procedures to control risks (Control)
  • Only use PPE after all other controls are in place
  • Supervise and monitor to make sure controls work (Discipline)
  • Always protect all workers together before protecting individuals
  • Review your controls when new technology or methods become available
  • Give clear instructions to all employees about risks and safety
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Why the hierarchy of controls matters

The hierarchy of controls is perhaps the most important concept in practical health and safety management. It provides a systematic approach to deciding how to control workplace risks, working from the most effective measures (eliminating the hazard) down to the least effective (personal protective equipment).

This is not just good practice - it has a legal basis. Regulation 4 of the Management of Health and Safety at Work Regulations 1999 requires employers to implement preventive and protective measures on the basis of the general principles of prevention set out in Schedule 1.

The nine principles in full

Schedule 1 of MHSWR 1999 lists these principles in priority order. They are derived from Article 6(2) of the EU Framework Directive 89/391/EEC and remain part of UK law after EU exit.

The practical hierarchy: ERICPD

In practice, the 9 principles are distilled into the hierarchy of controls, often remembered using the mnemonic ERICPD. This framework guides every risk control decision you make:

Applying the hierarchy: worked examples

Example 1: Hazardous substance exposure

  • Eliminate: Can you stop using the substance altogether? Use a water-based process instead of solvent-based?
  • Reduce: Substitute with a less hazardous substance. Use a lower-toxicity cleaning product.
  • Isolate: Enclose the process. Install local exhaust ventilation (LEV) to extract fumes at source.
  • Control: Limit exposure time. Rotate workers. Implement permit-to-work procedures.
  • PPE: Respiratory protection, gloves, goggles - only if higher-level controls are insufficient.

Example 2: Working at height

  • Eliminate: Can the work be done from ground level? Use a long-reach tool instead of climbing.
  • Reduce: Minimise the height and duration of work at height.
  • Isolate: Use platforms with guardrails, scaffolding, or mobile elevated work platforms (MEWPs).
  • Control: Establish safe systems of work, training, and supervision for height work.
  • PPE: Fall arrest harnesses - only when collective protection is not reasonably practicable.

Example 3: Noise exposure

  • Eliminate: Can you use a quieter process or equipment?
  • Reduce: Use silencers, dampers, or noise-reduced tools.
  • Isolate: Enclose the noise source. Create noise refuges for workers.
  • Control: Limit exposure time. Designate hearing protection zones.
  • PPE: Ear defenders or plugs - with proper selection, training, and maintenance.

PPE is always the last resort

The legal requirement under Schedule 1 principle (h) is clear: collective protective measures must take priority over individual protective measures. If an HSE inspector finds you relying on PPE when higher-level controls are reasonably practicable, you may face enforcement action.

PPE only protects the wearer, depends on correct use, and can fail. Engineering controls and elimination protect everyone automatically.

Links to specific regulations

The hierarchy of controls appears throughout UK health and safety regulations:

  • COSHH 2002: Explicit hierarchy for controlling exposure to hazardous substances
  • Manual Handling Operations Regulations 1992: Avoid, assess, reduce
  • Work at Height Regulations 2005: Avoid, prevent, minimise
  • Noise at Work Regulations 2005: Eliminate, control, PPE
  • Control of Vibration at Work Regulations 2005: Eliminate, reduce, PPE

In each case, the legal structure reflects the same principle: deal with hazards at source before relying on individual protection.

Official guidance and resources