Key takeaways
  • The hierarchy ranks control types by reliability: elimination, substitution, engineering, administrative, PPE.
  • Higher controls work regardless of behaviour. Lower controls depend on people doing the right thing every time.
  • A risk assessment where every control is a rule or a glove has not applied the hierarchy, it has skipped it.
Why the order matters
Higher controls do not depend on anyone remembering

A guard works on the worst day of someone's life. A rule works only when the person is trained, present, unhurried and paying attention. That is the entire argument for the order.

The five levels

  • Elimination. Remove the hazard entirely. Do not do the task, or design it out.
  • Substitution. Replace with something less hazardous: a water-based solvent, a lighter component, a lower voltage.
  • Engineering controls. Isolate people from the hazard: guarding, interlocks, local exhaust ventilation, barriers, lifting aids.
  • Administrative controls. Change how people work: procedures, permits, training, signage, rotation, restricted access.
  • PPE. Protect the individual at the point of exposure. The last line, not the first.

What each looks like in practice

For manual handling of a heavy component: eliminate by having the supplier deliver it in a position that removes the lift; substitute by splitting into lighter units; engineer with a vacuum lifter or a height-adjustable table; administer with a two-person lift rule and training; issue gloves and boots. Most assessments produce only the last two.

Why teams skip to the bottom

  • Higher controls usually cost money and take time; a procedure can be written this afternoon.
  • The higher levels require changing the process, which needs authority the assessor may not have.
  • Administrative controls feel like action and generate documents, which look like progress.
  • Nobody asks why a higher control was rejected, so the question is never answered.

Making the hierarchy auditable

Add a column to the risk assessment recording, for each risk, what was considered at each level and why it was not adopted. This costs a few minutes and changes the conversation, because 'not reasonably practicable' has to be written down and justified rather than assumed.

Combining levels

The levels are not exclusive. A guarded machine still needs a safe system of work and appropriate PPE. The point is that the higher control does the load-bearing work and the lower ones cover residual risk, rather than the lower ones carrying the whole burden.