Paris Firefighters Used This Remote-Controlled Robot to Extinguish the Notre Dame Blaze

Colossus can carry heavy hoses into spots that are too dangerous for human firefighters to enter

7 min read
Two photographs showing the Colossus robot inside the Notre Dame cathedral. The left photos shows Colossus in action. The right photo shows Colossus with firefighters surveying damage.
Colossus the robot, first announced by Shark Robotics in 2017, assists the Paris Fire Brigade in fighting a fire at Notre Dame Cathedral on 15 April 2019.
Photos: Shark Robotics

The Paris Fire Brigade has seen its share of logistical challenges, but the massive conflagration that consumed parts of the Notre Dame Cathedral on the night of 15 April required a fight of epic proportions. The cathedral is 856 years old and built in a style that makes it almost structurally impossible to contain a fire. The site doubles as both a wildly popular tourist attraction and a holy site for Christians. Defending this symbol of French heritage would require all the tactical and physical power the Brigade had at its disposal—human and otherwise.

Soon after firefighters arrived at the scene, the cathedral’s giant spire began to show signs of collapsing into the building. For onlookers, a collapse would be a devastating loss of a religious and cultural monument; for the Paris fire brigade, it would threaten the lives of the more than 400 firefighters already on the scene.

It was time to bring in the robot.

Colossus, a remote-controlled firefighting automaton designed and built by Shark Robotics, looks a bit like an army tank—if the tank were painted fire-engine red, retrofitted with a massive hose instead of a gun turret, and shrunk down to the size of a large dog. It can project water up to distances of 250 meters. With its heat- and water-resistant chassis and powerful all-terrain treads, Colossus led the way into the most dangerous areas of the cathedral, extinguishing flames and clearing away debris that could have harmed its human operators.

Firefighters are seen with a robot firefighter called Colossus, made by French robotics company Shark Robotics, outside Notre-Dame Cathedral on April 16, 2019 in Paris, France.Colossus was not sent to the attic or roof of Notre Dame for fear that its treads could damage the cathedral’s delicate architectural structures.Photo: Aurelien Meunier/Getty Images

By midmorning on the 16th, the blaze was completely extinguished. The cathedral’s giant spire, along with the roof and internal scaffolding, had collapsed; a nation was in mourning. But no human lives were lost, and Colossus was well on its way to being an international robot celebrity.

To learn more about Colossus and the role it played in this effort, IEEE Spectrum spoke to Cyril Kabbara, cofounder of Shark Robotics.

IEEE Spectrum:Why bring robots into firefighting? What can Colossus offer to the Paris Fire Brigade that the Brigade couldn’t do on its own?

Cyril Kabbara: The main reason we started working with the Paris Fire Brigade—and the main advantage of this robot in particular—is avoiding injury to human firefighters and victims. That has been our focus from the very beginning. Beyond that, there is the added benefit of the kinds of techniques that a robot can use that would be much harder for humans—things that require transporting heavy equipment or moving through very dangerous areas. Our goal is to keep firefighters safe and free from the heavy work that distracts them and takes time away from solving problems quickly and effectively.

Spectrum:Is Colossus always being remotely controlled by an operator or does it also have autonomous functions?

Kabbara: Colossus is always being piloted remotely by a firefighter trained to operate the machine. We actually offer three kinds of control stations that can be linked to the robot in order to adapt to the needs of the situation. There is the standard station, which can transmit a signal to the robot from up to 300 meters away. You can also use the tablet or smartphone version, which works with ruggedized personal tech for iOS and Android systems. The last version is the vehicle-mounted control station. We created a lot of options for how to control Colossus with a human operator from afar because remote control is the best way to minimize danger and maximize efficiency.

Spectrum:What kinds of sensors and cameras does Colossus have, and do they provide information that human firefighters couldn't get without the robot?

Kabbara: Colossus acts as a kind of technical support station to the firefighting team by supplying information from its sensors to both the remote pilot and the other firefighters in real time. This is an essential function in the dangerous circumstances the workers face when they enter an emergency scene, and it’s very important that all the information is in the same place, as opposed to in different sensors that the team has to carry with them into the building.

Firefighters obviously want to know the temperature, and Colossus has an advanced thermometer, but they can also use the robot to find out whether there are any hazardous chemicals in the air besides smoke. Colossus also has separate sensors that can tell if there’s an NRBC threat—in English, CBRN, for chemical, biological, radiological, and nuclear. Those are types of hazardous materials that might be planted at a site on purpose, probably in a terrorist situation.

Photo of Colossus inside the Notre Dame cathedralColossus, shown here inside Notre Dame, is designed to fight fires under extreme conditions that would be unsafe for human firefighters.Photo: Shark Robotics

There are also optional accessories that we can add on to different models, depending on what the robot will be doing, and some of those are also kinds of sensors. The robot’s four different day and night cameras with object-recognition capabilities can be really helpful in the middle of a rescue, where the smoke and shadows can make it difficult to see what you’re looking at.

Spectrum:How do you prevent heat and water from damaging the robot’s sensors, computers, and motors?

Kabbara: Colossus was built with an aluminum-welded aeronautical steel chassis that is completely waterproof and highly heat resistant. Working with members of the Paris Fire Brigade to develop the design helped us create something that can withstand these extreme conditions with minimal maintenance so that human firefighters can rely on it in the middle of a rescue. Colossus is designed to last between 10 and 12 hours without any servicing or recharging.

Spectrum:Is the robot designed to use a larger hose and more water pressure than the regular hose that human firefighters handle?

Kabbara: The main advantage of Colossus is that employing it reduces the chances of human injury. Unlike humans and animals, Colossus is built to withstand the extreme heat you feel when you go into a burning building for up to 8 hours at a time, and it will not feel pain or sustain damage if a building collapses on top of its chassis. However, it is also able to take over some of the less strategic aspects of firefighting. For example, Colossus is capable of moving wounded fighters to a safe place or carrying up to one ton of equipment across the scene. The heaviest hose it can lift would take three or four human firefighters to lift otherwise. This enables the human firefighters to devote their full attention and energy to aspects of the fight that only humans can do, like making decisions about the best way forward.

Spectrum:How much does the robot cost?

Kabbara: Each robot costs about €130,000 to 200,000 (roughly US $150,000 to $225,000). The range is quite substantial because the design of the robot is modular and there are many features that are optional, so our clients can customize their robot to a certain extent in order to better suit the job that it will have.

Spectrum: At Notre Dame, it seems that the fire started in the attic and roof, which quickly became engulfed in flames, and it was hard for firefighters to reach that area. Could they have sent Colossus to climb the stairs and go to the roof? Or would you need a different kind of robot, smaller and more agile?

Photo of Colossus going up a staircasePhoto: Shark Robotics

Colossus is actually capable of climbing stairs of up to 30 centimeters in height, as well as treading water and navigating indoor and outdoor slopes of up to 45 degrees. In the case of the Notre Dame fire, Colossus was not sent up to the attic because its treads might damage some of the more delicate architectural structures there.

Spectrum:How do Colossus and the rest of the brigade work together? Can humans and robots really make an efficient team?

Kabbara: Colossus is really more like a tool than another firefighter. Adding a robot version of a human firefighter to a team would not be very helpful, but we’ve had success with our approach, where humans control the decision-making and robots do the lifting, dragging, carrying, and the more dangerous tasks that would be a big risk for humans.

Big physical tasks like this sometimes require a change in Colossus’s shape, which is why we built the robot to be as modular as possible. Whether the firefighters need to transport a heavy hose or equipment or bring a human victim to safety, Colossus can take on a new form in less than 30 seconds and without any additional tools, like screwdrivers or wrenches. That quick change is very important because when you’re working in a burning building, the moment you figure out what you need, you really need it!

Spectrum:What was the process like to make Colossus part of the firefighting team?

Kabbara: Actually, it was quite an involved process. Colossus has been in service with the Paris Fire Brigade for two years, but before that, we needed several years to develop the technology to make it suitable for real firefighting situations. We are a team of engineers, not firefighters, so we had a lot to learn from our partners on the Brigade. They would tell us what made sense and what would never work in a real fire. They could explain what kinds of situations were more or less likely and what the dangers were that we engineers didn’t even know about. Training the firefighters to work with Colossus was actually much easier than developing the robot to work with the brigade from the start. Most of the people we have trained to pilot Colossus have only needed around half a day to learn how to operate the machine properly.

Spectrum:What can we expect from Shark Robotics and robots like Colossus in the future?

Kabbara: Since we announced Colossus in 2017, we’ve seen massive demand in a number of industries for this kind of ground-based drone tech. The military, industrial projects, private security firms—they all see a use for these robots because they deal with the same sort of physical danger to human workers that firefighters face. We’ve had to recruit a dozen new engineers to fill all these orders, but I’m happy that we are going to be able to protect more people by giving them tools to do their job safely.

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