Drones and the Hierarchy of Control

Drones and the Hierarchy of Control

We were recently involved in a job with one of our heavy industry clients to provide support with auditing the structural condition of a large exhaust stack. The stack was approximately 60 metres high, and had ladders and a number of platforms spaced all the way to the top rim. A great project for a drone!

There had been some concern that the ladder and platform connections may no longer be in a good enough condition to support the required loads – i.e. the weight of the crew that needed to access them.

As part of the risk assessment for the job (and all risk assessments that we take part in), the hierarchy of control was used to determine the best controls for the risks – the most significant risk of course being a fall from heights due to a platform or ladder failure.  For those unfamiliar with the hierarchy, it looks like this:

hierarchy of control

The hierarchy of control – the higher the control type, the more effective it is.

In order to meet the highest control – Elimination – we needed to ensure that no person was required to step foot on any plant that was potentially damaged or unsound.
Previously to achieve this, the site team would engage either a very large EWP (elevated work platform – see image below) or a Crane and Man box.


A sample EWP

Whilst both these options satisfy the ‘Elimination’ criteria, they do have some shortcomings. The area in which this stack was located was quite busy with lots of plant and piping, so there was really only one location where they could be set up. This meant that access all the way around the stack was not possible. This may not always be a serious concern, but in this case it meant that parts of the platform would be missed from the inspection, so the team looked at another option – the Nebo drone inspection team.

A drone inspection is particularly suited to this type of inspection. Ability to access all sides of the stack, with only a very small access area (landing zone). The drones super zoom meant that we could get high definition images of even the smallest details. This made this solution an easy choice, without even getting in to the significant cost savings compared the crane or EWP.

The outcome of the inspection was that there was a number of failures present in the platforms. The site team was right to not let anyone access for a physical inspection. Here is a sample of an image captured by the drone.

Platform image from drone

The platform at the top of the stack – image taken using the Nebo drone


failed connection image from drone

A zoomed in version, showing the failed connection.

The site team can now work on a plan of action to deal with the issues with full information, achieved without putting anyone at risk of falling.

If you have a similar situation that you think might be suitable for a drone, contact us and we can come and have a chat to see if drones are the right choice.

Do you currently spend a lot on EWP hire, or have structural inspections that you keep putting off because they are in the ‘too hard’ basket?

Luke is an engineer and manager of Nebo Project Engineers, as well as a licensed drone pilot. If you want to contact him directly, email luke@neboengineering.com.au