Papers by Hans-Peter Leimer
Restoration of buildings and monuments, Dec 1, 1995
The main task of an executed research programme was to determine the moisture behaviour of non ve... more The main task of an executed research programme was to determine the moisture behaviour of non ventilated inclined roof-systems with fully insulated rafters in combination with understating sheets. A double climate chamber was used to perform the test. In addition and as a comparison with the test result, dynamical two dimensional model calculations were carried out in order to describe the moisture behaviour of the roof system. Both the test and the calculation lead to the conclusion that the considered systems can be carried out without any objections concerning building physics. Thus, it is possible to reduce high initial wood moisture contents rapidly and thereby the risk decreases decisively. As expected, variable climatic zones show different moisture developments in the roof-system which may finally make the application of a vapour barrier obsolete. Dr.-Ing. Hans-Peter Leimer; (geb. 1956), Studium der Architektur (TFH Berlin) und des Bauingenieurwesens (TU Braunschweig), Promotion HAB Weimar. Bis 1989 selbständige Tätigkeit im Ingenieurund Architekturbüro Leimer & Raschper, Wolfenbüttel, und wissenschaftlicher Mitarbeiter am Institut für Baukonstruktion und Holzbau (TU Braunschweig). Seit 1990 selbständig im BBS Ingenieurbüro für Baukonstruktion, Bauphysik und Sanierungstechnik, Wolfenbüttel. Lehrauftrag an der TU Braunschweig, Gebiet 1 'Angewandte Bauphysik', Gebiet 2 'Historische Baukonstruktion'. Referatsleiter des Referats 8 'Fachwerk' in der WTA, Leiter der Arbeitsgruppe 8.1 'Bauphysik'.
Bauphysik, Feb 1, 2006
Reisen in Wohnwagen und Reisemobilen gewinnt in der mobilen Welt immer größere Bedeutung. Hierbei... more Reisen in Wohnwagen und Reisemobilen gewinnt in der mobilen Welt immer größere Bedeutung. Hierbei werden zu unterschiedlichen Jahreszeiten verschiedenste Regionen bereist. Grundlegende Voraussetzung ist hierbei die Aufrechterhaltung eines angenehmen Raumklimas im Innern des Fahrzeuges.
Moisture problems resulting from conventional vapor control strategies have inspired the developm... more Moisture problems resulting from conventional vapor control strategies have inspired the development of innovative vapor retarders. The performance of two such retarders, the water permeable Hygrodiode and the humidity controlled Smart Retarder, has been examined by laboratory and field tests. The results show that both innovative retarders improve the drying potential of an assembly compared to a traditional polyethylene film. The degree of improvement depends on the application. The Smart Retarder is favored for walls because summer condensation is less pronounced than in roofs where both retarders perform equally well. For flat roofs with possible leaks in the membrane the Hygrodiode could be of advantage due to its capacity to absorb and transport liquid water.
Energy Procedia, Nov 1, 2015
Increasing urbanization and climate change are one of the greatest challenges in the 21st Century... more Increasing urbanization and climate change are one of the greatest challenges in the 21st Century. Many regions already face different negative impacts on cities such as growing local pollution, solid and liquid waste, traffic congestion and noise. A growing consumption of fossil fuels in cities leads to increasing CO2-emissions accelerating climate change. All over the world and also in China, cities are trying to reduce their carbon footprint. In that context, the concept of so called "low carbon cities" is promoted. Currently, 79 cities in China are considering low carbon concepts. To build a low carbon city is not an easy task as there are various barriers to be removed, such as financial, traditional and institutional barriers. Building belong to the most traditional and slow-changing innovative areas in industry. Further solutions are different for hot and warm climates than for cold climates. Due to a very fragmented and divided structure in smaller enterprises and in different areas, a holistic approach is hardly to get.
Restoration of buildings and monuments, Feb 1, 1998
In letzter Zeit werden in geneigten Dächern vermehrt diffusionsoffene Unterspannbahnen (USB) eing... more In letzter Zeit werden in geneigten Dächern vermehrt diffusionsoffene Unterspannbahnen (USB) eingebaut. Diese Bahnen ermöglichen bei einer Wasserundurchlässigkeit das Entweichen von Feuchte aus der Konstruktion, sei es aus den abtrocknenden Sparren oder aus anderen die Konstruktion belastenden Feuchteprozessen. Die Ermittlung der Wasserdampf-Diffusionswiderstandszahl dieser Bahnen nach den herkömmlichen Prüfverfahren zeigen je nach Prüfverfahren und Randbedingungen jedoch stark schwankende Ergebnisse. Aus diesem Grund wurde ein übliches, nichtbelüftetes Dachsystem mit Sparrenvolldämmung im Hinblick auf die Abhängigkeiten unterschiedlicher s d-Werte untersucht. Hierbei wurden die Kennwerte des s d-Wertes der Unterspannbahnen aus Versuchen nach DIN 52615 sowohl konstant als auch in Abhängigkeit von der umgebenden Luftfeuchte angesetzt. Die Berechnungen zeigen, dass in Abhängigkeit des angesetzten s-Wertes einer USB erhebliche Gefährdungen (annähernd bis zu einem Faktor 10) der Dachsysteme möglich sind. Für eine genaue Beurteilung der Dachsysteme wurden hierauf Vorschläge für die labortechnische Ermittlungsmethode des 'wahren' s d-Wertes gemacht.
Restoration of buildings and monuments, Apr 1, 1999
When restoring the facade of historical frame work it is important to consider the rules of conse... more When restoring the facade of historical frame work it is important to consider the rules of conservation of monuments as well as the aspects of building physics (sound insulation, protection against heat, moisture and fire). The investigation of sound insulation of historical constructions as frame work fronts is still in its infancy. As part of a research program "Improvement of the heat protection of architectural monuments" of the federal foundation for environment in Germany soundmeasurements at frame work walls were carried out to ascertain the sound reduction index. The investigated walls consisted of a timber construction with brick infillings and different plaster and facing systems. Repairing frame work constructions the infillings could partly be damaged and get loosened from the construction. Therefore the infillings have to be replaced completely. Different kinds of material can be used for the exchange. For example the wall can be filled out with lightweight plaster. In cooperation with the companies Marmorit and Knauf the sound transmission of frame work walls with different infillings were measured to investigate the sound insulation of these constructions.
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Papers by Hans-Peter Leimer