Sensor predicts glass breakage

May 4, 2010
The sensor is located on the rim of the sheet of glass. It is linked to the building control systems by cable. (© K. Dobberke/Fraunhofer ISC)

( -- Modern glass façades inform the architecture of major cities throughout the world. In recent years, however, there have been cases of broken glass, with collapsing facades endangering passers-by. Now, a special sensor can detect micro-fissures and warn of impending breakage beforehand.

The Pompidou Center, the pyramid entrance to the Louvre, the Munich Uptown tower and Berlin's Spreedreieck office triangle: When constructing modern buildings, architects readily choose constructions designed of glass and steel. Nowadays, entire glass façades are no longer a rarity. Meanwhile the constantly recurring reports of collapsing façade elements have prompted the federal ministry for transportation, construction and urban development to mandate regular inspections of potential risk. The problem: The monitoring instruments in use until now merely register the sound of breaking glass. Thus, they can only ascertain breakage once it has occurred, and are unable to warn of looming peril in a timely manner.

German researchers at the Fraunhofer Institute for Silicate Research ISC in Wurzburg in collaboration with industry partners have developed a sensor that even detects micro-fissures of five millimeters in length, and thus point out the need for repairs early on - long before the glass actually breaks. "We attached several piezoelectric sensor actuator modules in a window pane. Four are situated on a one square meter surface, on the edge of the pane at a distance of one meter from each other. One sensor actuator module produces an ultrasound wave that is registered by the others. If the remains constant, then the pane is not defective. If it changes, then this indicates a fissure caused during transport or due to an installation error. This fissure most often emanates from the edge of the pane and is initially invisible. It is only as time goes by that it gets larger due to various factors, like fluctuations in temperature," explains Dr. Bernhard Brunner, working group manager at ISC.

The sensors are linked to the building control systems by cable. The data received there is analyzed automatically. If a fissure occurs, an alarm goes off. "We have succeeded in integrating our sensors, which measure 15 by 15 by 0.5 millimeters, into laminated glass. They can be integrated between both glass sheets as early as the manufacturing process. Therefore, the sensors can test the glass for transport defects even before installation," adds Brunner.

Glass manufacturers and glass refiners also have the opportunity to conduct tests when goods are received or shipped. Yet the new safety system not only warns of breakage; it also offers comfort functions: The sensor-actuator modules are coupled with temperature and light sensors that - depending on incident light - target individual louvers for opening or closing, and thereby control room temperature.

Currently, the project partners are looking for façade builders who want to use the sensors on a test basis. The experts are displaying a prototype at the Sensor+Test trade show in Nuremberg, Germany, from May 18 to 20.

Explore further: Glass sensors measure weathering effects

Related Stories

Glass sensors measure weathering effects

September 26, 2004

The corrosiveness of a specific atmosphere can be established in a few weeks by thin slices of special glass. The sensors are capable of monitoring the outdoor environment as well as indoors, for instance in sensitive production ...

Vigilant windows

March 17, 2009

Is someone sneaking around in front of the window trying to break in? Windows and doors are now being sensitized to suspicious movements: they can detect whether and how quickly something is moving. If it is a person, the ...

Researchers develop new reversible, green window technology

March 3, 2009

Ben-Gurion University of the Negev (BGU, Israel) researchers have developed a new, highly energy-efficient window technology, featuring two reversible panes that will save energy all year round in homes and office buildings.

Researcher Develops Sensor to Detect E.coli

September 24, 2006

As the Food and Drug Administration takes days to track down the source of the E. coli outbreak, Dr. Raj Mutharasan is optimizing a sensor that can enable growers to do the job themselves in a few minutes.

MU engineers develop safer, blast-resistant glass (w/ Video)

September 10, 2009

To protect from potential terrorist attacks, federal buildings and other critical infrastructures are made with special windows that contain blast-resistant glass. However, the glass is thick and expensive. Currently, University ...

Recommended for you

When words, structured data are placed on single canvas

October 22, 2017

If "ugh" is your favorite word to describe entering, amending and correcting data on the rows and columns on spreadsheets you are not alone. Coda, a new name in the document business, feels it's time for a change. This is ...

Enhancing solar power with diatoms

October 20, 2017

Diatoms, a kind of algae that reproduces prodigiously, have been called "the jewels of the sea" for their ability to manipulate light. Now, researchers hope to harness that property to boost solar technology.


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.