18,432 Readings Daily

2023 Author : Hannah Pearcy | [email protected] . Last modified: 2023-11-26 11:39

In the Berlin district of Lichterfelde, the facades of five multi-storey buildings have been energetically optimized with various thermal insulation composite systems from Caparol. The heat transfer and moisture absorption of the facade insulation panels and the plastering system in all five core-refurbished houses is to be determined over several years and evaluated using hygrothermal measurements. Dr. Ayman Bishara, research assistant at the Dr. Robert Murjahn Institute, explains the research project in an interview with Malerblatt.

Dr. Bishara, which insulation materials or insulation panels do you take a close look at in Berlin?

Dr. Bishara: We used five ETICS systems with four different insulation materials. These include two ecological insulation materials, hemp and wood fiber, and two conventional insulation materials, mineral wool and EPS.

What is the exact structure of the individual thermal insulation composite systems with regard to insulation thicknesses, plastering systems and additional materials?

Dr. Bishara: The insulation thickness of all five ETICS systems was dimensioned so that all outer walls have a heat transfer coefficient in accordance with the Energy Saving Ordinance (EnEV) (0.18–0.21 W / m²K). Insulation thicknesses of 14 to 20 cm were used.

How is the surface on which the ETICS applied?

Dr. Bishara: The surface (exterior plaster stock) is a mineral scratch plaster. This was tested for its strength in all five houses in accordance with standards. This means that all ETICS were dowelled and fastened in accordance with DIN and manufacturer's instructions on an intact surface, which was also treated with a primer.

What exactly is being measured? Which building physics parameters does your interest in knowledge target?

Dr. Bishara: The hygrothermal behavior of the construction and the indoor air is measured. Specifically, the temperature and relative air humidity are measured on the insulation boards below the exterior plaster level (between the exterior plaster and the insulation board) and in the adhesive level (between the solid wall and the insulation board). In addition, the temperature and relative humidity of the room air.

How many measurements are taken in a day, week, month and year? How much measurement data is there?

Dr. Bishara: We have a measuring interval of five minutes, which means that a measurement of the temperature and the relative humidity of 32 data loggers is continuously recorded every five minutes. This results in a measurement volume of 18,432 readings per day.

Can you please describe the research design in more detail? Which investigation method do you use to evaluate the data streams?

Dr. Bishara: In addition to our own evaluation methods developed at the RMI, particularly with regard to hemp, we use the WTA information sheet to evaluate moisture data for wood fiber and hemp. The evaluation of mineral wool and EPS is carried out according to DIN EN ISO 13788 and the evaluation of the indoor climate according to DIN EN ISO 15026/13788 (normal occupancy and high occupancy).

How does this methodical approach differ from the usual investigation methods?

Dr. Bishara: We are able to use much more advanced technology than before. The measuring system developed by us enables us to record hygrothermal measurement data non-destructively, whereby thermal bridges due to sensor technology are also significantly lower than with previous systems.

Is there such a thing as external supervision of research activities? Who does the validation of the measured results and checks the plausibility of the conclusions that you and your colleagues draw at the RMI?

Dr. Bishara: The RMI is an accredited and classified testing and research institute, an internal and external audit is carried out regularly. We also work together with universities and other testing and research institutes to exchange know-how. We provide our practical research results as teaching aids for universities and also benefit from the close cooperation with the chairs. For example, two master's theses on the Märkische Scholle in Berlin are being supervised by the RMI and the Beuth University Berlin.

It doesn't happen every day that five equally large multi-storey buildings stand side by side in a street and each of them is insulated with a different ETICS from a single manufacturer - how do you ensure the objectivity of the measurements?

Dr. Bishara: We ensure this through a scientific approach, because scientific work always requires objectivity. Ultimately, we are also interested in the real results.

So there is no risk of interest-based influencing by industry?

Dr. Bishara: The RMI is an independent, accredited and classified testing and research institute. This means that our tests and research are based on purely scientific and standard-oriented methods.

You have applied for a patent for the newly developed method - does that mean that this special research design should only be used by the Dr. Robert Murjahn Institute? Or do you want to grant usage licenses to other laboratories and possibly also companies?

Dr. Bishara: After the patent application has been submitted, we are of course pleased if other institutes, researchers and experts also use our method. The aim of our research and development is to promote sustainability in construction, which is why we are always interested in an exchange of know-how on a scientific level.

For what period of time is scientific research into changes to insulation and building components

under real conditions planned?

Dr. Bishara: Three to four years.

Where will you publish your results?

Dr. Bishara: At national and international conferences as well as in specialist magazines.

Dr. Bishara, thank you very much for the interview.

Further information on the long-term trial: bit.ly/2qHKOvy