The work at height hierarchy explained

When talking about working safely at height, we often reference the ‘work at height hierarchy of controls’. But what exactly are we talking about?

The hierarchy is a set of guidelines laid out in the Work at Height Regulations 2005 which aims to reduce the number of accidents that occur when working at height.

Since the introduction of the regulations, the UK has achieved some of the lowest fatality and injury rates in the EU, with just 0.55 fatalities per 100,000 employees, compared with 3.14 in similar industrial 

countries like France. However, the Health and Safety Executive reports that 18% of total fatalities occurred as a result of work at height, which highlights the enduring importance of guidelines such as the hierarchy.

The hierarchy is divided into 8 levels. When attempting work at height, you should apply the guidelines laid out in the hierarchy from top to bottom and follow them as best you can to ensure the work you aim to carry out goes smoothly and safely.

Work at height hierarchy

Level 1: avoid work at height

The topmost level of the hierarchy might seem obvious, but avoiding work at height truly is the only way to entirely negate the risk. This begins right at the design stage, where architects and design managers should minimise the need to access the roof, i.e. by placing plant and equipment at the ground level where possible.

If the work is not at ground level, you should first analyse whether the work could be carried out without accessing the roof. For example, if cleaning windows or gutters, could you use an extendable reach and wash system?


Level 2: preventing using existing workplace

If work at height is entirely unavoidable, it is preferable to prevent the issues from occurring rather than minimising their consequences. If an area of the roof is already safe thanks to the implementation of the correct type of equipment, the work should be carried out here.


Level 3: prevent using collective equipment

If the correct equipment does not already exist in the area where the work will be carried out, then your first thought should be for collective, or ‘non-user participant’ protective equipment such as guardrails. Collective equipment is preferable due to the fact that it will protect anyone who accesses the roof, regardless of training or competence. However, generally, only those with training and experience should be accessing the roof.


Level 4: prevent using PPE

If collective equipment such as guardrails are not practical on your roof, perhaps due to size or restrictive design, then the alternative would be personal protective equipment, or PPE. Personal systems include lifelines or anchor points, and will require the user to be an active participant by connecting to them via harness and lanyard. These systems are effective, but only if the user is properly trained in their use, and if they actually choose to use the system, as such, they are lower on the hierarchy than collective equipment.


Level 5: minimise distance with collective equipment

If the risk of fall cannot be prevented, then the distance you can fall should be minimised as far as possible. In the first instance, this should be achieved with the use of a collective system such as safety netting directly below the working area.


Level 6: minimise distance with PPE

An alternative, but less preferable, solution to reducing the distance of a fall, is personal protective systems such as lifelines used in ‘fall arrest’. These do not restrain you from accessing the roof edge, but will arrest your fall using a lanyard, harness and shock absorber.

These systems, whilst effective, also come with a host of drawbacks: they require a clearance distance of at least 4m or more to be effective, as well as comprehensive training and a rescue plan. They can also cause strain on the body and cause physical injury.


Level 7: minimise consequences using collective equipment

Whilst safety netting can be used to reduce the distance of a fall, such as in level 5, if it cannot be installed directly below the work area then the last resort is to install it lower down and reduce the impact of the fall rather than the distance.

Due to the greater risk of injury to the body from the fall and the inevitable impact, even into the net, this solution is far less preferable to the others.


Level 8: minimise consequences using instruction and training

The very last tier of the hierarchy and the baseline requirement for carrying out safe work at height: all workers accessing the roof should be aware of the dangers and well trained in how to handle them before the work begins.

Workers should be competent and properly trained in how to use any fall protection systems utilised on the roof, and be aware of all safety guidelines and regulations.


These guidelines, when implemented correctly, will improve your chances of successfully carrying out work at height when it becomes necessary.

Work at height is inherently dangerous and one of the leading causes of death and injury at work in the UK, so it is vital these guidelines are followed.

For a full site survey and advice on how you can improve safety for your employees and visitors, call Harcon on 0161 777 4230, or use our online contact form.

Click here for a high quality version of our work at height hierarchy infographic.