Hot town, summer in the city — it's nothing new, but ways to handle the heat, humidity, and stormwater haven’t changed much since the invention of the sewer system.
One solution offered by architectural researchers is known as a “green roof” — a roof covered in living, growing plants to soften the effects of heat, flooding, noise, and stormwater runoff.
Five platforms at the the Research and Demonstration Facility aat Virginia Tech in Blacksburg, Virginia, were used to test various depths of “green” roofing. The thickest growth is in the foreground, with unplanted growth material and finally reflective roofing material in the distance.
Elizabeth J. Grant, an assistant professor of architecture and design at Virginia Tech, will present ways for architects to determine the most effective depths of green roofing for stormwater control on Thursday at the International Conference on Building Envelope Systems and Technologies — also known as ICBEST — in Aachen, Germany.
“With growing numbers of people moving into cities, it is crucial to give architects and builders tools to make good decisions about green roofs,” Grant said. “These systems are on the rise not just because they represent a link to the natural world that is scarce in the city, but because they work. Extremes of temperature and rainfall are becoming unpredictable as climates change, and vegetated roofs help us build resilience in a rapidly changing world.”
With Kenneth Black and Jim Jones of the School of Architecture + Design, the team generated equations that can predict the effectiveness of vegetated roof installations to control stormwater runoff relative to temperature, humidity, and frequency of sunlight and rainfall.
Green roofs use the sun to transform water into water vapor, which provides cooling as a byproduct. In the same way, these vegetated roofs reduce stormwater runoff and flow rates, which in turn helps prevent sewers from overflowing and stream banks from eroding.
“Our research should give architects and designers justification that they are helping the environment by incorporating green roofs in their plans,” Grant said. “We are bridging the gap between science and design.”
The researchers built a variety of test platforms with depths of green roofing ranging from about 2.5 inches to 6 inches deep at the Research and Demonstration Facility managed by the College of Architecture and Urban Studies in Blacksburg, Virginia.
Alongside the platforms were a weather station and a rain gauge to measure rainfall, temperature, humidity, wind speed and direction, and solar radiation.
Of 74 rainfall events included in the study, all of the treatment platforms, including the unplanted, growing-medium-only roof, retained significantly more runoff than a white reflective roof membrane with no vegetation or growing medium used for comparison.
Deeper platforms hold more stormwater runoff, but overall green roofs retain about 50 percent of the stormwater compared with about 6 percent for the normal, flat roof.
Light colored roofs or reflective roof surfaces have also been mentioned as solutions to sweltering city temperatures, but recent studies warn that they may merely redistribute heat without reducing it, and they don’t address runoff problems as well as vegetated roofs.
The next step in the research is to analyze the data at five-minute intervals to compare the delays in runoff at the treatment platforms, which is important for understanding sewer-system loads and stream erosion.
Written by John Pastor
Katie Gehrt | Virginia Tech
Working comfortably in summer heat
02.06.2016 | FIZ Karlsruhe – Leibniz-Institut für Informationsinfrastruktur GmbH
NEST: building of the future is up and running
23.05.2016 | Empa - Eidgenössische Materialprüfungs- und Forschungsanstalt
Munich Physicists have developed a novel electron microscope that can visualize electromagnetic fields oscillating at frequencies of billions of cycles per second.
Temporally varying electromagnetic fields are the driving force behind the whole of electronics. Their polarities can change at mind-bogglingly fast rates, and...
Breakup of continents with two speed: Continents initially stretch very slowly along the future splitting zone, but then move apart very quickly before the onset of rupture. The final speed can be up to 20 times faster than in the first, slow extension phase.phases
Present-day continents were shaped hundreds of millions of years ago as the supercontinent Pangaea broke apart. Derived from Pangaea’s main fragments Gondwana...
Scaffolding and specialised workers help with the delivery – Heidelberg biochemists gain new insights into biogenesis
A type of scaffolding on which specialised workers ply their trade helps in the manufacturing process of the two subunits from which the ribosome – the protein...
Scientists at the Helmholtz Zentrum München have developed a new mass spectrometry imaging method which, for the first time, makes it possible to analyze hundreds of metabolites in fixed tissue samples. Their findings, published in the journal Nature Protocols, explain the new access to metabolic information, which will offer previously unexploited potential for tissue-based research and molecular diagnostics.
In biomedical research, working with tissue samples is indispensable because it permits insights into the biological reality of patients, for example, in...
Chemists at the University of Basel have succeeded in using computer simulations to elucidate transient structures in proteins. In the journal Angewandte Chemie, the researchers set out how computer simulations of details at the atomic level can be used to understand proteins’ modes of action.
Using computational chemistry, it is possible to characterize the motion of individual atoms of a molecule. Today, the latest simulation techniques allow...
15.07.2016 | Event News
15.07.2016 | Event News
11.07.2016 | Event News
22.07.2016 | Information Technology
22.07.2016 | Physics and Astronomy
22.07.2016 | Life Sciences