Plaster And Environment

Just a few years ago, it was enough to refer to safe raw materials or to point out that they are ultimately standardized products that have been used for decades. In the meantime, that has changed. The VDPM explains the situation.

Author: Ludger Egen-Gödde

Are plasters environmentally friendly? The early conclusion: A clear yes from Dr. Dieter Schübl, head of the VDPM working group on environment and hazardous materials management. He explains: “Today, evidence is required and requirements are made. Scientifically proven facts have to be presented. This applies both to customers and in dialogue with the relevant authorities and the legislative bodies”. Dr. Hans-Joachim Riechers, General Manager of the VDPM adds: “We started research more than ten years ago together with the Fraunhofer Institute for Building Physics and other renowned institutions. Once there are requirements and limit values in the room, it is difficult to change anything else."

Transparency and learning effect

The concept of making things open and transparent right from the start and not doing research in the "quiet closet" has proven its worth. According to Riechers, this was associated with the risk that even unexpected results would be made public. "We are not afraid of that. Responsible manufacturers are required to be transparent. In addition, we also learn in the context of research and can change our products if it turns out that this is necessary.”It is also important to the initiators of the research that public bodies and institutions are involved, which will later have legal limits and requirements decide.

Rainy facades

What is research about? Plastered facades are exposed to wind and weather. When it rains they get wet and rainwater can run down the facade, hit the ground and seep away there or get into the sewage system. “We used to assume that a plaster was quasi inert. But we had no evidence of this. That is why we have carried out extensive field studies. Defined plaster surfaces were exposed to the weather for many years and the water that ran down was collected and analyzed after each rain. An enormous effort, as Riechers notes. "It turned out that fabrics were also removed from a plastered surface and transported on with the rainwater," recalls Dr. Schübl. Today it has become a big topic, then the knowledge was rather new.

What has research done so far? "We have a huge collection of data from the measurements of the field trials carried out. We know which substances are removed from which plasters over time and in what quantities. We not only checked the plasters in the field, but also in the laboratory and have a large data collection here too,”said Schübl. “What we cannot yet assess exactly is the path that the released cargo takes when it gets into the environment. When is a limit exceeded and what does that mean for our plasters?”Adds Riechers.

There are no special limits for plasters. For this reason, the generally applicable limit values for groundwater are used. These are the so-called "insignificance thresholds" - limit values that must not be exceeded when entering the groundwater. But how does the rainwater running off the facade get into the groundwater? Before it arrives there, the rainwater that runs down seeps through the various layers in the ground and is distributed. Fabrics can be retained or even broken down in the ground. It is then greatly diluted in the groundwater itself. Here a model has to be developed with which this scenario can be described as realistically as possible. "Only then can we say whether and when a limit value may be exceeded," explains Riechers the connection. It looks even differentwhen the water is discharged into the sewage system.

PhD position created

All of these relationships are currently being examined in a dissertation at the Technical University of Munich. Not only the members of the VDPM participate in the financing, but also other partners. With the professor Dr. rer. nat. habil. Brigitte Helmreich from the Chair of Urban Water Management at the Technical University of Munich has found an expert in this field to supervise the doctoral student. When the next generation of European standards starts, there will also be so-called “environmental requirements”. "It would be ideal if we had completed our model development by then," Dr. Riechers into the future. "We could then say: If a plaster remains below certain values in the laboratory test, then in reality no danger to the environment is to be expected." This would achieve a major goal.

Further information:

www.vdpm.info