A research team from the department ETRO-VUB led by Professor Johan Stiens and Dr Ali Pourkazemi has developed a radar that can look inside and through walls, ceilings and floors. The device will be useful for renovators or restorers of old buildings for which no detailed technical plan exists. The device can calculate the exact thickness of the wall and the size of pipes running through it, and identify cavities, providing valuable information for those carrying out renovation works.
At the start of 2021, Belgium had a total of 4,590,838 buildings, representing a value of €1,650 billion. Eleven million Belgian residents combined use almost 4.6 million buildings in which they either live or work. Worldwide, it is estimated that there are more than half a billion buildings, with a value of €165 trillion.
“There is nothing else to which so much added value can be attributed to as buildings, in Belgium or in the rest of the world,” says Stiens. “With many of those buildings we don’t really know exactly what’s in the walls, floors and ceilings anymore. There is no digital twin of the building. You can hardly imagine that for other systems. For a simple television, we know exactly what components go into it. But we don’t know that for many houses. You can’t just break a wall or a ceiling. These are usually major interventions that can cause serious damage.”
The wall radar uses the material-dependent propagation velocity and reflection of electromagnetic waves. Conventional radars emit electromagnetic waves that contain many frequencies (like white light contains many colours). All these frequencies are reflected in a different way, leading to an enormously complex signal and making it practically impossible to deduce the thickness and the materials used for all layers. The ETRO radar sends a special signal that uses complex mathematical models to derive the cross-section of the wall with everything in it from the reflected image.
The applications are numerous. Stiens points to the construction sector, detecting insulation materials or leaks in walls and floors, detecting invisible concrete rot and professionalising restoration projects. It can be used on stone, wood, glass and concrete and can even pick apart layers of paint with a thickness of 100 micrometres.
“It doesn’t work on metals, but of course you see them in the picture as obstacles,” he says.
Because there is a lot of commercial potential, Stiens and his colleagues are preparing to set up a spin-off, which for the time being is called TRMCo. The project receives financial support from the Brussels-based science and innovation agency Innoviris and, as a promising innovative project through Smart Hub, from the province of Flemish Brabant. The spin-off should be operational in 2023.
Professor Johan Stiens, ETRO
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