Assessment System for Sustainable Building
Worldwide, systems for the evaluation and certification of buildings have been developed, in order to promote ecological and energy efficient development. Therefore at the moment there are a number of systems – one hears of “First Generation Systems” in which chosen aspects of sustainability are assessed at a very high level. To promote sustainable building,
the activities as part of the international (ISO) and European Norms (CEN) for a holistic approach were abandoned with the involvement of the five qualities of sustainability. Based on that, the first systems of certification for the second generation have been developed in previous years, which assess the sustainability of buildings by means of a holistic approach to observation. This will offer investors and planners not only a comprehensive overview of sustainable construction, but also tools which will simplify the planning and implementation of sustainable aspects.
The Federal Building Ministry promoted the development of a national system of evaluation which is based upon the national environment, legal regulations and norms etc. and can be interpreted for construction in Germany. After a two year Federal Building Ministry co-operation period with the German Sustainable Building Council, the first proposition for national sustainability criteria, including calculation and assessment methodology could be presented to the specialist public. This system uses a holistic assessment procedure which considers the life cycle of a building and a comprehensive quantification. For the actual observations of the life cycle, the first 50 years of a building are worked into the calculations. As Life-Cycle-Costs (LCC), the costs of construction (DIN 276), the construction use costs (DIN 18960) and the demolition costs are additionally considered.
The Assessment System for Sustainable Building (BNB) provides scientific, well-founded and planning based evaluation processes for offices and administration buildings. The goal is to describe and evaluate the quality of the sustainability of buildings and annexes and their complexity. This is to obtain a higher quality of construction using the planning, beginning with the building construction, operation and maintenance, repair up to the demolition of buildings and annexes. Evaluation is conducted using transparent and objectively comprehendible regulations.
Protective goods and goals of sustainability can be extracted for the construction sector for the three dimensions of sustainability. Alongside the ecological, economical and sociocultural aspects, the functional and technical properties (technical quality), the planning and implementation (process quality) and the, in part, local characteristics are decisive for the description and value of a building. This has extended the hitherto three columns of sustainability to five quantifiable qualities of sustainability – informatively supplemented by the local characteristics. The various aspects of sustainability interact directly with each other, so that the goal becomes a holistic and simultaneous assessment of every aspect.
The five main groups of criteria are defined exactly in the Assessment System for Sustainable Building with currently 46 criteria files and can be measured or evaluated according to quantifiable amounts. The criteria can be prioritised within the superior main criteria groups according to their relevance for the protection goal by use of a factor of importance from 1 to 3 (low to high amount of importance). The factors of importance are determined in close agreement with the Roundtable Sustainable Building working groups and the Federal Building Ministry.
The individual criteria are assessed according to determined rules. In total, each criterion can receive a maximum of 100 points, according to the relevant rules of calculation, whereby the value 100 always corresponds to the defined target value. The main groups of criteria will be assessed separately and collated, using the determined priority to form a total grade of performance and with that a final result. In the title stating the results of the evaluation, the building will be presented alongside the individual values which lead to the end result. The building can be award the quality levels of bronze, silver and gold dependent on the total grade of performance. The evaluation is carried out by an auditor and will be subject to a test of conformity.
Practical Aids and Tools
The holistic assessment and evaluation of the sustainability aspects in civil construction requires the most diverse basic data. The Federal Building Ministry has therefore initiated the requisite projects using the Roundtable’s actors in the past. Now, a series of requisite basic principles and practical aids is available. That amongst other things is an aid for the life cycle analysis (green balancing, life cycle cost analysis). In addition this ensures that the sustainability aspects are included in the planning and construction phases and that this is comprehensively documented.
A substantiated assessment and choice of construction products during the planning and construction phases is the core job for sustainable plans, construction and management of buildings, which more and more architects are confronted with. WECOBIS (Web-based Ecological Building Material Information System) offers comprehensive, structured, neutral information to health and ecological aspects of construction products and also online links with further sources of information and data. The system supports the observation of life cycle phases with information regarding the choice of raw products, creation, treatment, use and re-use.
The Ökobau.dat, the development of the first German building material database for the determination of global, ecological effects, provides a simplified basis for data for the ecological evaluation of buildings. As part of a Zukunft Bau project19, the researcher had developed a number of data records in XML format for the further use in existing life cycle calculation tools with the support of the German Construction Materials Industry. Using so-called style sheets, currently around 650 construction materials or construction and transport processes are described in terms of their effects. For every data entry, alongside the ecological details, details are also given regarding the source data such as reference unit, validity, data quality etc.
For the evaluation of sustainability in buildings during the life cycle, the Useful Lives of Construction Parts to be used are very decisive, since they shed light on the frequency a construction part has been exchanged within a specified observation period. They can be used as an orientation aid or recommendations, should no exact details be available from the planners or the product manufacturers. The guidelines are based, currently, on textbook calculations, expert interviews and statements from building product manufacturers and their societies. The information is published on the Information Portal Sustainable Building. For the evaluation of federal buildings according to the BNB system, the details stated in the table are to be used.