Abstract
Building industry belongs to one of the most polluting industries. Therefore, the minimization of energy requirements of buildings, as well as the reduction of emissions produced within the buildings life cycle has become a point of interest of many engineers, designers, architects or researchers. Every process in construction sector requires large amounts of energy, which mostly originate from fossil fuels, emits substantial amounts of CO2 or SO2 and produces waste or pollution. Existence of buildings is thus responsible for more than one third of green house gasses produced, as well as for consumption of about the same share of energy.
The selection of building materials used for construction of building is usually performed on the basis of technical and economical parameters. However, a question of environmental performance is increasingly taken into consideration with the principal aim of reaching sustainability, but is still not sufficient. As a matter of wide range of various parameters with different importance it is sometimes difficult to select the best-suited construction.
In this paper a selection of building materials to construct external walls with technical, as well as environmental criteria in mind using multi criteria selection is presented. 5 compositions of external walls made of aerated concrete blocks with thickness of 300 mm and 375 mm were included into evaluation. In 4 structures the thermal insulation material (2 types of mineral insulation or 2 types of polystyrene) was added. Multi criteria analysis was performed on the basis of assessors’ preference as well as on the basis of their considerable importance. Evaluation included technical parameters, such as thickness of wall, weight of used material, quantity of layers; thermal-physical parameters (calculated U-value, surface temperature) and environmental parameters, which were calculated on the basis of available materials’ database. Environmental assessment was focused on 3 parameters: embodied energy of materials expressed by amount of Primary Energy Intensity, amount of CO2 emissions as Global Warming Potential and quantity of acidification gasses as Acidification Potential. Calculated values of environmental indicators were in range from 554.56 MJ/m2 to 689.25 MJ/m2 in the case of Primary Energy Intensity. Amount of calculated CO2 emissions (Global Warming Potential)ranged from 49.26 kg CO2eq/m2 to 58.88 kg CO2eq/m2 and values of Acidification Potential were calculated in range from 0.1296 kg SO2eq/m2 to 0.2063 kg SO2eq/m2. Environmental performance was compared with conventional evaluation and the optimal construction from the evaluated external walls was chosen.
