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Drones: The sky's no limit

Once derided as little more than a passing fad for tech-heads with pocket money to burn, the use of drones in construction is now taking off at sites across the UK. Tim Miller looks at how drones could change site management for good.

Drones have hit the headlines in recent times thanks to a series of high-profile – and not always positive – incidents.

Last October, a drone flying a controversial flag caused an international football match to be abandoned; in the following months, planes landing at both Heathrow and Leeds-Bradford airports reported near-misses with drones; and in March, an attempt to fly drugs and a mobile phone into HMP Bedford was foiled only by the drone operator’s ineptitude (it crashed into barbed wire atop the prison’s walls).

More quietly, the construction industry has been experimenting with the flying machines – officially known as unmanned aerial vehicles or UAVs – in a variety of ways.

No longer are firms baulking in the face of the technology; rather, innovative thinking is being sparked by the potential uses for drones.

UAVs are quickly making a difference on and off sites, providing opportunities and benefits for both main contractors and their suppliers.

Picture perfect

While the use of helicopters to take aerial shots of construction sites at various stages of completion is not uncommon, drone alternatives can offer immediate cost benefits, which opens up the world of high-quality aerial photography to smaller companies.

New technology is no longer the preserve of big contractors with deep pockets: drones retail from as little as £90.

Even more state-of-the-art machines cost in the low thousands – a reasonable outlay for a one-off purchase.

“For a helicopter to come over and take photographs [costs] somewhere in the region of £500 a visit,” says Willmott Dixon operations director Peter Gleave. “The drone we use now takes 14-megapixel photographs. It’s paid for itself.”

Such a cost benefit may be enough to attract many businesses to invest in a drone, but it’s what can be done with the imagery that could make a real difference to working practices.

Plans and designs for projects are often subject to unforeseen setbacks and essential programme changes, but Bouygues Bâtiment International head of research and development projects Magdalena Pyszkowska says visual information gathered during drone flights can feed into design and modelling processes.

“You can catch everything from different angles – you get information you cannot get normally,” Ms Pyszkowska explains.

“We can build a 3D model from the [drone] photogrammetry, which is quite impressive. You can superimpose the photogrammetry of the project over the design model.”

By combining drone imagery with 3D models produced before a project begins, firms can plot a scheme’s progress on the ground against computer-aided designs and plans, digitally, and in real time.

Client confidence

It’s not just contractors that benefit from the ability to compare real-time output against a planned programme of work, though. The detail and accuracy of information being captured by drones also allows clients to be better informed.

“When you show [the imagery] to people who are not physically involved in the project, they see quickly where we are,” Ms Pyszkowska says. “They’re really impressed by the vision of the site during the construction period.”

“It gives the client a lot of confidence that what you’re reporting is actually correct because of the scale of what you’re looking at”

Peter Gleave, Willmott Dixon

The ability to deliver a better quality of report on the progress of a project is leading to more engaged relationships with clients, too.

“It gives the client a lot of confidence that what you’re reporting is actually correct because of the scale of what you’re looking at,” says Mr Gleave.

Firms can also make use of data recorded during drone flights as evidence of construction milestones achieved, when, and to what standard. This gives clients peace of mind during the construction process, but also allows contractors to validate their work on a project should anything go awry in future.

“After the delivery of a building, you have proof that the work was well done,” says Ms Pyszkowska. “Normally we don’t keep this kind of detail of documentation.”

For companies uncomfortable bragging about their achievements, a comprehensive record of a project from a drone’s-eye point of view can help to prove the value of their work.

A better kind of bid

It isn’t just the construction phase where UAVs are coming into their own – drones are offering the opportunity for contractors to impress clients even earlier: during the bidding process.

Firms can use drones to get to grips with the scale and layout of a new site, or quickly and cheaply obtain imagery of an existing building or environment where works are to be carried out.

For example, with the regeneration of older buildings, a short drone flight can swiftly deliver information to a contractor that accurately depicts the condition of façades and hard-to-reach areas of a building, for an indication of the scope of works needed.

“On a project that we’re pricing, good aerial shots of the site [help] plan the programme offering going to the client”

Peter Gleave, Willmott Dixon

For the project operative in charge of the drone, “the digital imagery is that good that they can do an assessment as to whether they’ve got to go and physically do work, or do a further, more detailed survey”, says Mr Gleave.

This level of information can be shared with a client to create an open dialogue at bid stage, revealing early on precisely what is required. Using drone-captured material in bid documents also immediately enhances the power of a contractor’s tender when they’re detailing the job.

“It’s one thing putting an artist’s impression in [to the client] but it doesn’t really bring it to life,” he says.

“On a project that we’re pricing, good aerial shots of the site [help] plan the programme offering going to the client.

“The quality of the bid documents we’re putting in means we’re ahead of the curve.”

Efficient logistics

The mixed-use Flemingate development in Yorkshire, where Willmott Dixon is on site, has given the contractor an opportunity to exploit the aerial view to make better and safer logistical decisions.

By gaining an overview of a whole site from the sky, plans can be put together much more cohesively than from the limited information otherwise available from the ground.

“When you walk the site on foot, you don’t pick everything up. Site boundary conditions, what’s over the fence, what your neighbours look like – all those things are not very clear,” says Mr Gleave.

As a result, on sites where space is limited or access is constrained, being able to manage a project’s logistics more effectively can help progress on the ground keep pace with the programme of work.

“There’s a lot of logistical planning for lay-down areas and available space,” he adds. “Once you’ve got the drone up and you’ve got that aerial perspective, you can plan your material deliveries and efficiencies around where works and operations are going on far more effectively.

“Planning what you’re actually doing on the site ahead of the project starting is a massive benefit.”

Safety from the sky

Using drones also offers potential safety and security benefits for subcontractors working on sites.

Being able to see the real-world view of a live site gives contractors a means to improve the health and safety performance of their subcontracted staff, at a low cost.

“If you’ve got guys in a site induction and you’ve taken photographs the week before from the air, you can show people around that project in detail, in a very safe environment, but still give a live view of the site,” says Mr Gleave.

“Normally we’d have to do that from a two-dimensional drawing, which wouldn’t be representative of what the site is like at that point in time.”

“We can see all of the small issues on site that we cannot otherwise check. You can see if your team is working correctly”

Magdalena Pyszkowska, Bouygues Bâtiment International

Furthermore, a business could use UAVs to monitor the condition of particularly hazardous site areas over time, inspecting such things as the security of scaffolding following severe weather.

“We can see all of the small issues on site that we cannot otherwise check. You can see if your team is working correctly,” says Ms Pyszkowska.

Although it sounds like something out of George Orwell’s 1984, visual data taken by drones could have a significant and positive impact on the safety of staff carrying out work on site.

Drone imagery could relay to site managers how successfully health and safety practices are being implemented, with the learning passed back to teams during the project so that behaviours are improved in a matter of days rather than months.

Flying into the future

Take-up of the technology is not so much a question of why contractors should be integrating drones into everyday activities on sites, but what’s stopping them.

Bouygues has been trialling UAV technology in the US, where regulation on drones is more relaxed than in the UK, and perceptions about their use are considered to be more forward-thinking.

With tighter control of the use of drones in the UK and on the continent (see box), it is up to contractors to demonstrate the positive effect they would have for their business, clients and the building’s end user.

“In Europe, [there is a perception] that the drone is like a spy. We don’t talk about the advantages for planning on construction sites, for the safety of people,” Ms Pyszkowska says.

“[But] if we can work with the aviation authority, we can deliver some value for everybody.”

“There’s a lot of innovation that’s coming into play to improve what we’re doing. The technology that we’re using absolutely amazes people”

Peter Gleave, Willmott Dixon

To ease the use of drones into a business and find out how they can deliver benefits, innovative contractors could create an ambassadorial role for drone use, suggests Ms Pyszkowska, with the freedom to experiment.

“You need an internal partner who is able to test what works and implement the advantages,” she says.

Mr Gleave cautions that investment in training will clearly be required. But drones represent a glimpse into an exciting future for the industry – and for those who may be interested in working in it.

“At the end of the day, it’s driving positive behaviours,” says Mr Gleave. “The perception around construction can be driven by what’s seen on TV – DIY disasters and that sort of thing – whereas the reality is that professionally qualified people work right across this industry.

“There’s a lot of innovation that’s coming into play to improve what we’re doing. The technology that we’re using absolutely amazes people.”

Flying drones: top tips

The Civil Aviation Authority provides guidance and regulations on the safe use of drones. Contractors should bear in mind the following points:

Permissions

  • Permission from the CAA is required if the unmanned aerial vehicle is being flown on a commercial basis e.g. payment for services such as imagery captured.
  • Permission from the CAA is also required if an unmanned aerial vehicle fitted with camera equipment is being flown in congested areas, or close to people or property not under the operator’s control i.e. on public land.
  • Permission is not required if the aircraft will not be flown close to people or properties, and ‘valuable consideration’ (i.e. payment) is not exchanged for the flight.

Regulations

  • An unmanned aircraft must never be flown beyond the normal, unaided ‘line of sight’ of the person operating it, generally measured as 500 m horizontally or 400 ft (122 m) vertically.
  • An unmanned aircraft fitted with a camera must always be flown at least 50 m away from a person, vehicle, building or structure.
  • An unmanned aircraft fitted with a camera must not be flown within 150 m of a congested area or large group of people.

Readers' comments (2)

  • hawkeye

    The distance regulations (particularly on confined London & urban sites) proves the most stringent for UAV operators, and across most sites Hi-Level masts can still operate safer, closer and more cost effectively than a UAV .. without the legal air or operational restrictions. Albeit whilst not reaching to 120m or possibly the wider photogrammetry data .. but on most sites that's not necessary anyway.

    One of the masts main advantages is that there is no flight time limitation, are somewhat less weather dependent and they can stay up for hours (not minutes) at a time, e.g., for time-lapse, event sequences, detailed building façade surveys and still offer a safer and cost effective method of obtaining hi-level imagery on most sites.

    There again, traditional aerial photography from aircraft or helicopters can cover many sites in a few hours, unlike both UAV's and Masts.

    It's all a matter of horses for courses, and which ever proves the most cost effective ... as it's just another platform to obtain aerial views one just cannot see from ground level.

    Apart from UAV's being the flavour of the month, don't forget the alternatives and the benefits they still have to offer.

    Unsuitable or offensive? Report this comment

  • A very interesting article, demonstrating the effectiveness of using aerial photography in the construction industry. Many companies have been providing these services to the construction industry for many years. The increasing interest and popularity surrounding drones has had a very positive effect in promoting the significant advantages of using aerial photography.

    Drones whilst costing significantly less to buy than a helicopter or plane their operation is labour intensive and disruptive when used on a busy construction site where health and safety is a principle concern. As a consequence this may put off a construction company from purchasing their own drone and choosing instead to use an outside contractor. When comparing the costs of contracting a drone company or an operator using a conventional helicopter or plane it can be the case that the more cost effective option is to use a conventional aircraft. This can also provide additional benefits of reducing health and safety risks along with the ability to use higher quality equipment providing is some cases superior results to drones.

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