CPD: Using drones in construction

Aerial view of St Willibrord’s church, Manchester, taken as part of an Ascent survey for the Diocese of Scotland

Robert Barnes of LC Building Consultants and Cassandra Zanelli of Sheffield solicitor Taylor&Emmet advise on the impact of drones, their legal requirements and the consequences of non-compliance.

It is rare for a day to go by without a drone-related story being mentioned in the press or on social media. Unfortunately, the majority of these stories are about near-misses with commercial aircraft. This is perhaps hardly surprising, as history shows that the drone has a dark and threatening past.

In the mid-1800s, Austria sent unmanned, bomb-filled balloons to attack Venice, while the 1940s saw Germany use the infamous V1 and V2 flying bombs to cause widescale destruction in London and the south-east during the second world war. Today military drones are used regularly in the fight against terror.

Drones are also known as Unmanned Aerial Vehicles (UAVs), and have been defined by US Department of Defense as a “powered, aerial vehicle that does not carry a human operator, uses aerodynamic forces to provide vehicle lift, can fly autonomously or be piloted remotely, can be expendable or recoverable and can carry a lethal or nonlethal payload”.

There are a number of different types of commercial drones in use. Excluding the military drones, there are two main types:

Fixed-wing drone

These have a more conventional aeroplane look. These robust, lightweight drones are propeller driven and can fly for up to an hour, covering vast areas at a high altitude. They are predominantly used for geographic mapping, agricultural crop monitoring and offshore applications.

The information they gather can be used to provide accurate 3D mapping or detailed thermal imagery. However, the main disadvantage to their use is that they need a large uninterrupted area for taking off and landing.

Multirotor drone

More commonly known as quad-, hexa- or octocopters, these drones are extremely manoeuvrable as they take off vertically and are able to hover and hold their position. They come in many different sizes, ranging from something that will fit in the palm of your hand to 2m in diameter.

A multirotor can fly on any axis and at speed, making it ideal for filming or inspecting buildings and bridges, especially where space is tight. They are also able to fly indoors.

Multirotors are mainly used for TV and films, restricted access inspections, construction monitoring and thermal imagery. For instance, the quadcopter used by LC Building Consultants’ Ascent division takes HD quality video at 60 frames per second, which can then be converted into high-quality stills. The main disadvantage is that the flight times are short when compared against a fixed-wing craft, ranging from 10-25 minutes.

The technology is advancing at a blistering pace and it is clear that there will be an important role for the drone to play within the construction industry. A great deal of research and development is being carried out on a myriad of potential uses. From restricted access condition surveys to specification compliance inspections, and from health and safety monitoring to thermal imaging, there is an argument for using a drone in most construction disciplines.

Legal requirements

The advances in technology have resulted in some drones becoming more affordable for the general public and there has been a huge increase in the domestic market. Unfortunately, most of the reports we are reading about result from these leisure users not flying within the requirements set out by the Civil Aviation Authority (CAA).

All drone users must comply with the CAA requirements, otherwise they face being prosecuted, losing their equipment and having to pay a hefty fine.

The authority’s requirements are summarised as follows:

  • The person in charge of a small unmanned aircraft may only fly the aircraft if reasonably satisfied that the flight can safely be made.
  • The person in charge must maintain direct, unaided visual contact with the aircraft at all times.

The person in charge of the aircraft must not fly:

  • In certain classifications of airspace unless permission has been granted;
  • At a height of more than 400ft (122m), or more than 500m horizontally;
  • Over or within 150m of any congested area;
  • Over or within 150m of an organised open-air assembly of more than 1,000 persons;
  • Within 50m of any vessel, vehicle or structure that is not under the control of the person in charge of the aircraft;
  • Within 50m of any person, unless they are under the control of the person in charge of the aircraft.

To operate a drone on a commercial basis, you must ensure that you have fulfilled the requirements of the CAA and obtain its permission. This involves: web-based training; a three-day ground school with examination; a one-day flight test; preparation of your operating manual; and valid insurance. This process takes around six months and costs around £2,000.

The CAA has a list of all approved drone operators within the UK; this can be viewed on its website by following this link.

The list includes around 1,400 licensed operators. The majority of the firms are specialist media or photography companies, but the list also includes several police forces, university estates’ departments and housing associations. And it also shows that dozens of firms in the construction sector have decided to qualify for licences on their own account, including Ove Arup and Berkeley Homes.

Drone use in construction

The use of drones is becoming more and more popular in the construction industry and is likely to become commonplace in the future. Data can be captured in high definition and in varying formats, and can be used in many different ways, including: 3D visualisations; progress monitoring; topographical data capture; safety inspections and monitoring; thermal imaging; asset assessment and condition surveys; and restricted access inspections.

Images can be transmitted live in high definition and potential issues can be assessed, with solutions agreed immediately.

A flight path can be predetermined and flown every hour, every day, every week or every month. The information can be used to report on progress against programme. Details of actual construction during different phases can then be reviewed against the original specification.

Safety assessments can also be carried out in real time, allowing updates to be provided instantaneously if required. This also helps to identify potential problem areas before they crystallise into serious issues.

The UAV can also be used to locate areas where the building’s fabric is not thermally efficient. This will assist the surveyor in:

  • Visualising energy losses, air leaks and moisture intrusion;
  • Detecting missing, damaged or  inadequate insulation;
  • Locating air leaks;
  • Finding moisture in insulation, in roofs and walls, both in the internal and the external structures;
  • Locating water infiltration in flat roofs or identifying destructive water damage; and
  • Detecting construction failures.

Drones are also being used to map out sites and provide accurate topological information. Computer generated imagery (CGI) can be used to provide 360 degree visuals, on top of the information captured by the drone, to show a 3D visualisation of the development. The benefits of being able to provide visuals in this way will not only assist in the marketing, feasibility and planning of a project, but will also assist the developer during construction.

Considering the use of drones

To help decide whether the use of drone would assist in the delivery of a project, consider the following:

  • Use: What specific application is required? These might include general construction monitoring/inspection, defect analysis, snagging, mapping, health and safety, heat loss or condition assessments etc.
  • Data: What type of data is required? Video, photographs, measurements? At what resolution or tolerance?
  • Location: Where is the drone required? Are there any geographical or regulatory restrictions?
  • Safety: Is it safer to use a drone to get the information required? Will it help avoid working at height or in a confined space?
  • Cost: Will it be cheaper to use a drone to get the information required when compared with more traditional methods, such as scaffold or mobile elevated working platform costs?
  • Operation: Use an operator who has experience within the construction industry who will fully understand your requirements.

The use of drones in construction will increase as technology advances. There are many different uses, which can help to improve safety, and reduce both risk and costs within the industry. However, drone use must always comply with the CAA requirements and a qualified, approved and insured operator should be used, to avoid vicarious liability.

Now answer the CPD questions (please note you must register or sign in first):