EN 15978-2011 pdf download.Sustainability of construction works – Assessment of environmental performance of buildings – Calculation method.
NOTE 2 The environmental assessment of the building excludes permanent construction works outside of the curtilage of the site such as construction of infrastructure for communication, energy, water, waste and transportation. A building on a site which requires such construction works will generate environmental impacts other than those strictly related to the building, The assessment of these environmental impacts and aspects is outside of the scope of this European Standard.
The object of assessment shall be described in terms of its physical and time-dependent characteristics.
7.2 Functional equivalent
The functional equivalent is a representation of the required technical characteristics and furictionalities of the building. It is the means by which the characteristics of the building are rationalised into a minimum description of the object of assessment.
Although assessments may be carried out on an individual object, they will in most instances form part of the process for the evaluation of decisions in relation to the object of assessment. This includes the decision whether to build new, or refurbishlreconstruct an existing building, the evaluation of the design options, locations, etc.
Comparisons between the results of assessments of buildings or assembled systems (part of works) – at the design stage or whenever the results are used – shall be made only on the basis of their functional equivalency. This requires that the major functional requirements shall be described together with intended use and the relevant specific technical requirements. This description allows the functional equivalency of different options and building types to be determined and forms the basis for transparent and unbiased comparison. If the assessment results based on different functional equivalents are used for comparisons, then the basis for comparison shall be made clear.
NOTE 1 If appropriate, the assessment results of the buildings that have different functional equivalents (e.g. design options fcx different types of buildings on the same site or the same types of buildings exposed to different conditions) can also be compared based on a common unit of reference. The choice of the common reference unit for all buildings being compared depends on a specific requirement of a technical, functional, environmental, socal or economic aspect, or combination thereof, which is common to all these buildings and Is linked to their corresponding functional equivalents.
NOTE 2 A common reference unit can be derived from the functional equivalent and be used to present the result of the Indicators of the environmental assessment relative to the functional equivalent. A common reference unit may be dimensionless or qualified with a dimension (e.g. per m2. per year, per employee, per room per year, per m per year).
When combining separate assessments of environmental, social (see EN 15643-3) and economic (see EN 15643-4) performance in a sustainability assessment of the same object of assessment, the functional equivalent used in the assessments of the individual dimensions of sustainability shall be the same.
The functional equivalent of a building or an assembled system (part of works) shall include, but is not limited to, information on the following aspects:
— building type (e.g. office, factory):
— pattern of use (e.g. occupancy);
— required service life.
NOTE 3 Other specific requirements and exposure to climate and to other conditions from the immediate surroundings may be relevant for inclusion in the information on the functional equivalent.
The client’s brief and regulations may provide information for defining the functional equivalent. Where this is not the case, the assessment shall include the assumptions made, the scenarios and the sources of information used by the assessor.
EN 15978:2011 (E)
Where no required service life is specified by the client or by regulation. the design life may be used, If the design life is used (which can be longer than the required service life), how it is derived shall be described, e.g. determined on the basis of empirical, probabilistic or statistical data.
NOTE 4 Eurocodes and ISO 15686-1 provide guidance on determining the design life of a building.
7.3 Reference study period
Assessments are carried Out Ofl the basis of a chosen reference study period.
The default value for the reference study period shall be the required service life of the building. Any deviations from this (see below) shall be clearly stated and reasons explained
The reference study period may differ from the required service life given for the object of assessment (Figure 4) depending on the intended use of the assessment, or on regulatory requirements or national guidance. However, in all cases, the assessment is based on the building life cycle (Figure 6). Therefore, the values for impacts and aspects shall first be calculated for the required service life (see also Clause 8).EN 15978-2011 pdf download.