Once upon a time, managers who wanted progress reports on construction sites would simply walk around the site and look at where things were at.

This is not the case, however, with London’s massive Crossrail project, where unmanned aerial vehicles (UAVs) or drones are being used to support activities such as site inspections, health and safety inductions, inspections of crane or scaffolding erection and hazard and safety identification. When a BBC team wanted to give Londoners their first real glimpse about what their new asset would look like, the team negotiated with Crossrail’s safety team not for a journo and cameraman to walk through but rather to year let BBC trained pilot Jon Bontoft loose on a drone which buzzed its way down the tunnels.

These new methods are delivering advantages over more traditional forms of site monitoring such as walk-arounds or fixed camera shots. Unlike walk-arounds, drones offer opportunities for speedy overviews of large sites along with the ability to quickly zoom in on areas of high risk or critical inspections. For safety inductions, images captured through drones are being used to update site plans faster and show where different works (and thus hazards) such as lifts and excavations are taking place. The 360-degree panoramic view offered by drones provides a more immersive and intuitive experience so as to enhance appreciation of potential hazards and site operation.

Crossrail is not the only project on which this type of thing is being done. Once per day in California, drones automatically patrol the site of what will be a fancy new downtown stadium for the Sacramento Kings. The images collected are fed into software which compares it to architectural plans as well as the construction plan and helps identify areas where work may be falling behind.

This is happening in Australia as well. A host of companies are lining up to offer drone photography for a range of functions throughout the design and construction process.

So what are the critical areas of opportunity, and how can safety and privacy considerations be managed?

According to Derek Feebrey, a director and photographer at aerial video and photography outfit Hoverscape, drones offer many benefits in terms of driving greater levels of productivity. Because drone imagery does not require use of scaffolds or abseilers, site inspections using drones can be performed much more quickly with lower levels of risk – the whole thing usually being able to be done within the hour, including setup. Drone imagery can also be built into inspection software that can be built into a model which can be then uploaded and shared with others in order to provide updates to contractors, clients and other stakeholders.

Whereas a walk-around captured a view from one vantage level only (ground level), drones are able to capture the whole building and do so in a way in which progress can be compared over different periods of time. It can also be used as a measurement tool to provide insight as to how much earth has been moved on a road building site or what the gradients are at certain points. All of this can be shared with directors or, say, contractors who are scheduled to do work on the site in the near term.

“It’s information that can be captured quickly and shared globally,” he said. “It’s the ease of information and the detail of information.”

Moreover, it’s not just in the construction process itself that drone imagery can be used. In terms of marketing, drone imagery can provide potential purchasers of apartments brought off the plan with an accurate idea of what the view would look like from eye level on the 14th floor, for example.

Drone imagery can also be used to show the level at which certain selling points would kick in, such as landmarks which might come into view. In the development application, design and preconstruction phases, drone imagery can be used for a top-down view of ground mapping and getting the slope of the land, or to generate ‘view photography’ in order to work out where windows or balconies should be place to generate maximum advantaged from views and natural daylight.

Others agree that the benefits of drones are significant.

“Use of drones can assist in real time monitoring of the progress at the job sites and streaming of the real time progress data can greatly assist the construction and project management team for updating the schedule, tracking the variations and then taking precautionary measures for controlling the cost and time performance in the project,” University of Melbourne senior lecturer of construction management Dr Hemanta Doloi said. “Such real time tracking will then allow accurately forecasting of the resources requirements in the project.

“Use of drones certainly can assist in improving the safety of the job site and thereby reduce the eminent risks and accidents on site. There will be huge time savings compared to the traditional practices of walking around the site for physical inspections and as time is money, this will certainly result in cost savings as well. As the productivity is a measure of output over input, such time and cost savings in project will eventually result in increased productivity at the end.”

In terms of safety, drones are regulated by the Civil Aviation Safety Authority. As use in building and construction constitutes commercial use, anyone intending to use or operate a drone must hold a UAV operator’s certificate, whilst approval is required for those intending to fly above 400 feet. Flights are not permitted within three miles of an aerodrome or within 30 metres of a person.

Beyond that, Feebrey says it is imperative to operate within safety guidelines from a construction point of view as well as the Privacy Act. As with all forms of construction activity, standard safety measures such as site inductions, white card accreditation and safe work method statements were crucial, he said.

In terms of concerns surrounding workers being ‘filmed’ or ‘under surveillance’ Feebrey says people were generally not filmed or shot in a way in which they were identifiable. Where workers are often filmed are on big ticket items such as the first concrete pour, topping out of buildings or the lifting into place of major features such as glass facades. In such cases, he says, those involved are briefed about what is going on and why. Thus far, he says, Hoverscape has not run into any problems or resistance in this area.

Both the Australian Privacy Foundation and the Construction, Forestry, Mining and Energy Union declined an invitation to comment for this article.

Doloi acknowledges that any use of new technology has a ‘flip side’ but adds that the upside benefits are too great to ignore. As for safety, he says the ability of drones to zero in on risks onsite far outweigh those associated with the use of the drone itself.

“Of course, acceptance of a new technology  in the industry will be always slow and by the virtue of construction industry being a complex business with the involvement of multitude of stakeholders, diversity in skills and competence, logistics and varied expectations, full acceptance of drone as an enabler will take time,” Doloi said. “But eventually, drones will be accepted and the benefits will be multifold.”