Derivation of reliable simplification strategies for the comparative LCA of individual and "typical" newly built Swiss apartment buildings

class An abstract class is a base class with an incomplete declaration, as it represents a group of specific subclasses. It defines the basic characteristics of those subclasses without already implementing them in practice. In this UML diagram, "Component_lca" is one such abstract class. It represents for example the classes "Floor_lca" and "Ceiling_lca" and is linked to the classes "Layers_lca" and "Area_lca". The classes "Floor_lca" and "Ceiling_lca" therefore inherit the predefined links from the abstract class "Component_lca". Association An association represents a relationship between different classes. Associations which are depicted as an open arrow are uni-directional. The arrow indicates that of two related classes only one knows that the relationship between the classes exists. For instance, the class "Area_lca" is associated with different classification sets (the surface areas are classified according to SIA 416 [49], SIA 380/1 [34] and EKG by CRB). Generalisation Generalisation is an association between two classes, one inheriting all of its instances from the other. For example, the classes "Outer_wall_lca" and "Inner_wall_lca" both inherit the attributes of class "Wall_lca". Fig. 6.3: Dendroid database structure 36 6 Design of infrastructure for data acquisition Aggregation Aggregation is a special type of association. The associated classes have a different status: one contains the other. The class next to the rhombus contains the other class. For example, the class "Building_lca" consists of the classes "Excavation_lca" and "Backfill_lca". But the connection is not as strong as that of a composition. Composition Compositions represent an aggregation so strong that the contained classes cannot exist without the containing class. An example is the relationship between the classes "Building_lca" and "Component_BuildingEnvelope_lca". The latter depends strongly on the existence of the class "Building_lca". In other words, it wouldn't make any sense to collect data on the building envelope of a building that doesn't exist. In the following chapter, the characteristics of the apartment buildings from the collected sample are presented. 38 7 Data collection: Characteristics of the apartment buildings from the collected sample Unfortunately, it was impossible to derive the missing information from what was present so that in the end only 12 apartment buildings were analysed. The building sample under examination is composed of five massive, five medium weight and two lightweight timber buildings (as categorised by the Swiss standard SIA 380/1 [34]). The number of accommodation units ranges from 2 to 132, and the sizes of the buildings' energy reference area cover a spectrum from 350 m to 20 400 m. All of the buildings are situated in the northern to central part of Switzerland as displayed in the map in Figure 7.1. Table 7.1 gives an overview of the basic information on the sample (the buildings are ordered by the number of their accommodation units). The initial construction cost numbers in the table refer to the BKP structure by the Swiss Research Centre for Rationalisation in Building and Civil Engineering (CRB), where BKP 21 and 22 cover the initial building construction costs and BKP 24 the initial costs for the installations of the heating and ventilation system (for further details see Appendix A, p. A4 ff). The materials for the main construction parts of the buildings range from reinforced concrete, to different kinds of brickwork, to steel, timber and derived timber products. There is also a variety of insulation materials utilised within the sample. Figure 7.2 and 7.3 provide an overview of the amount of construction and insulation materials for each individual building. The information given takes into account construction as well as replacement of the building elements during a lifetime of 60 years. On the left-hand side, the total weight of each material is shown in the unit of tons [t], while on the right-hand side, the same weight is converted to the unit of kilograms per m of energy reference area and 1 year of building lifetime [kg/ma]. The denominator of this unit represents the defined functional unit of this LCA study (see chapter 8.1.3 for more details about the functional unit). In order to give an overview of the individual characteristics of each buildmfh05: mfh01: mfh07: mfh11: mfh10: mfh12: mfh08: mfh04: mfh09: mfh06: mfh03: mfh02: 20400.0