Height Safety

Hierarchy of Controls

Hierarchy of hazard control is a system used broadly in industry to minimise or eliminate exposure to hazards. This concept is utilised in industry, to be promoted as standard practice in the workplace – hence the reason it is frequently referred to in these documents as well as workplace health and safety programs across Australia/New Zealand.

Various illustrations are used to depict this system, most commonly a triangle. The sample below is an example of this depiction:

The hazard controls in the hierarchy are, in order of decreasing effectiveness/safety are:

  • Elimination
  • Substitution
  • Engineering controls
  • Administrative controls
  • Personal protective equipment

The hierarchy of controls are easily applied to fall protection and importantly always should be.

assessing ways to first eliminate, moving to substituting alternative means of safer access, followed by introducing engineering or administrative controls, are the most important steps to follow. In the absence of any alternate or ‘reasonably practicable’ means of access, then it falls to providing personal fall protection equipment as the last line of safety.

The focus of this website is to offer advice on managing fall protection issues across the full spectrum of the hierarchy of controls. The impact of the hierarchy of controls applied to the risk of height is now discussed.


Elimination simply means removing the risk of a fall completely. A simple example is shown below.

Eliminating a fall risk can be as simple as moving an air-conditioner from the roof to the ground, or more simply designing a building to ensure they are placed there in the first place.

Air-conditioners are commonly used across the world – and frequently require servicing – particularly those in commercial and industrial locations. Placing an air conditioner on a roof may offer some benefits for its performance or reduce noise, but it introduces additional risks of falls when maintenance is required to be done. Therefore simply moving the air conditioner to a ground based location eliminates the risk of a fall altogether.


This process simply means substituting one current means of access with another access that provides a substantially higher level of safety.

A temporary ladder can provide hazards – especially if it is the wrong type of ladder being used for the application. Substituting this with a permanently fixed ladder system may be a more suitable alternative. Going a step further and placing a set of steps on the side of the building is an even better way of eliminating the hazard, providing it is reasonably practicable to do so.

Engineering Controls

These controls essentially providing solution from a hazard as distilnct from removing the hazard altogether. As a consequence, they are lower on the hierarchy of control because they require a human interaction to institute the isolation procedure.

Administrative Controls

These involve implementing temporary barriers / measures to prevent people from reaching the area where a fall risk can occur. Unlike a permanent barrier, temporary measures are lower on the hierarchy because they can be moved or tampered with and are as only as good as the barrier and implementation method employed by those using them to control the hazards.

Personal Protective Equipment (PPE)

In a technical sense, PPE is considered to be the ‘measure of last resort’. When a person is required to wear a safety harness to protect them from being in a fall, all other means of practical access have been eliminated under methods proposed by the hierarchy.

Despite this equipment being designed for the most extreme circumstances, there are additional work methods that can be employed to ensure people are as safe as they can be when working at height. Such work methods include:

  1. Working in restraint – this means operating equipment in a way that prevents a person from being exposed to a fall arrest risk.
  2. Working in suspension – this can be on access equipment such as man-rated winches where people are carefully lowered to a place to perform work, or alternatively utilising the principles of rope access, where there is limited risk of a fall when work practices are employed to prevent a free-fall or fall arrest event
  3. Utilising Secondary Systems – Sound work practice in both fall arrest and rope access demands that you should always have a primary means of access and a secondary, redundant system that acts as a back-up in the event the primary means fails.

Training forms a vital part of all height safety work in terms of managing risks as well as knowing how to set up a safe system of work. Other sections of this site explain the minimum standards required to effectively implement safe systems of work and precautions that should be taken in height safety environments.