Principles
all non-structural facade elements are removed and the building is upgraded to meet current thermal insulation standards without necessitating any changes to the load-bearing structure. In addition, prefabrication of the timber panel elements requires an integrated and detailed approach to the design in which the architect, structural engineer, building services engineers and contractors are in contact with one another in the early design stages. Only in this way is it possible to accommodate the different dimensional tolerances in the reinforced concrete and timber components while optimising joint design and construction sequences.
in 1998, 178 countries have endorsed the joint “three pillars model” for sustainable development [1]. In accordance with this model, ecology (conservation of resources), economy (economic performance) and society (equal rights, peaceful coexistence, health etc.) must be given equal consideration to ensure, amongst other targets, sustainable building design and construction. Buildings cannot only make a significant qualitative contribution to the economy, culture and society, they are also highly important in the field of ecology. The energy they use is responsible for approximately 19 % of global CO2 emissions [2]. Furthermore, about 35 % of final energy consumption in Germany can be attributed to the buildings sector [3]. Consequently, the buildings sector has the potential of significant leverage in terms of ecological sustainability – by making more efficient use of energy and raw materials. Life cycle assessment (LCA) offers an effective approach to analyse the environmental sustainability of buildings. LCA calculates the energy and resource demand, waste and environmental impacts throughout the life cycle of the building, covering everything from the extraction of raw materials, the pro-
Sustainability The Brundtland Commission of the United Nations (UN) refers to “sustainability” in the following terms: “Sustainable development is development that meets the needs of the present without compromising the ability of future generations to meet their own needs.” Since the UN Conference on Environment and Development (UNCED) in 1992 and the Enquete Commission of the German Parliament
Production of interior load-bearing structure End of life of interior load-bearing structure Non-renewable primary energy [GJ]
Global warming potential [CO2eq]
Production of exterior elements End of life of exterior elements 200 180 160 140 120 100 80 60 40 20
7a
Hybrid construction
Concrete / masonry construction
b
Energy Efficiency
Since the introduction of the 1st German Thermal Insulation Ordinance in 1977, the requirements for the energy efficiency of buildings in Germany have steadily increased. The result is that “modern” buildings consume increasingly less heating and cooling energy. The German Energy Saving Ordinance (EnEV) 2002 included the provisions of the Heating Systems Ordinance (HeizAnlV) and con-
Ventilation for 50 a Heating for 50 a Hot water for 50 a
3,500 3,000 2,500 6 2,000 1,500 1,000 500
7
0 -500
0
duction of building components, the building’s construction and use to its eventual demolition and recycling. Hybrid construction using timber panel construction elements improves the ecological sustainability of buildings in several respects. It increases resource efficiency through the use of renewable raw materials and, if designed to be disassembled, the possibility to reuse materials and components in material cycles. Highly insulated timber panel construction elements contribute to energy savings during the use phase of the building (see “Thermal Insulation”, p. 33ff. and “Energy Efficiency”, below). In addition, hybrid construction has economic potential through cost and time savings (see “Economy”, p. 16f.).
Hybrid construction
Concrete / masonry construction
Various facade materials a Light-coloured masonry facing, student hall of residence Hanover (DE) 2017, ACMS Architekten b, c Fibre-cement sheets varnished in various colours, Neue Burse student hall of residence, Wuppertal (DE) 2013, ACMS Architekten Comparison of hybrid and concrete /masonry construction based on the example of a multistorey residential building in Penzberg (see example project p. 82ff.) a Global warming potential b Non-renewable primary energy
11
