One third of all global resources go into the construction of buildings. But if something involves lots of resources, it also represents an opportunity to save lots of resources. This is where four criteria under the overhauled DGNB System come in: deconstruction and disassembly, potable water demand and waste water volume, sustainable resource extraction and land use.
Sustainability is all about how people use valuable resources. This is precisely why we find it important to place emphasis on the circular economy as a central pillar of the DGNB System – right from the very beginning. The term ‘circular economy’ is used to highlight the need to minimise losses within building and material cycles. The aim is to enhance the likelihood of materials remaining available to future generations, ideally without loss of function or value. This keeps our dependence on natural resources to an absolute minimum, and in fact the best case scenario has to be that no more natural resources are needed.
How different parties use or draw on resources is reflected in a number of areas within the DGNB System. These four examples highlight the interplay between conserving resources and sustainability.
Deconstruction and disassembly
The DGNB believes in improving the effectiveness of current materials to ensure buildings don’t become a kind of ‘interim refuse site’ for the waste materials of the future. Instead they should offer a temporary storage facility for future building materials. To encourage this, the deconstruction and disassembly criterion acknowledges the use of building materials that are easy to recycle. Points are also awarded if materials are easy to take apart and separate according to their different constituents. The DGNB looks positively on projects that already put thought into such factors during the early planning stages.
For example, buildings that make use of previously used materials are awarded a circular economy bonus. This bonus is also given to projects that need no or less building materials. This underscores another important benefit that is achieved when people use fewer materials: they save money. There are also positive advantages for the users of buildings. The outlays for renovations, maintenance work or conversions can be lower.
Responsible and transparent sourcing
Although the intention is laudable, using absolutely no primary resources for the construction or upkeep of a building is sometimes simply not an option. So if using primary materials can’t be avoided, one should at least ensure materials are sourced or processed in keeping with acknowledged environmental and social standards. The DGNB’s aim is to minimise the negative impact of materials on the environment and society. There is no reason why anybody, anywhere should be made to suffer when resources are extracted. In actual terms, this means resource extraction should never involve child labour, forced labour, the illegal mining of materials, or a hazard to groundwater (for example due to chemicals). The more developers use responsibly sourced raw materials or replace them with secondary materials, the higher the score achieved for the sustainable resource extraction criterion.
With this criterion, the DGNB wants to encourage the use of products that have a transparent and positive impact on every stage of the value chain in environmental and social terms. Improving transparency makes it possible to promote an even greater understanding of sustainable and socially responsibly raw material sourcing and thus combat inappropriate practices.
Water is such an essential resource that the DGNB has given it its own individual criterion. To produce good drinking water, water is removed from nature, processed and prepared every day. This involves an elaborate system, just for us to have safe water. Afterwards, wastewater has to be treated again to extract harmful substances and pollutants before it can be returned to the water cycle. One of the aims of the potable water demand and waste water volume criterion is to protect the natural water cycle.
Another goal is to minimise the demand placed on drinking water. One key factor in cutting water consumption is how people use this valuable resource. This can be aided by introducing technology that helps people save water. Another factor that is addressed in certification is whether a building makes use of rainwater or grey water (sullage, i.e. water that is only lightly contaminated) by using it to flush toilets or clean buildings. Good practice is also rewarded by the DGNB if drinking water is not used to water plants or lawns, or if outdoor installations include measures to retain rainwater or reduce consumption. Ideally, rainwater should not be simply dealt with like wastewater. It should be allowed to seep back into the soil. Greened roofs (covered in vegetation) and carefully planned paved areas can also have a positive impact on certification.
If developers respond positively to these incentives, they also benefit in other ways. Saving drinking water also cuts operational outlays. Also, it reduces vulnerability to price rises and limited availability if buildings reuse wastewater and local resources are tapped into (by using wells and rainwater).
Filling gaps rather than leaving gaps
Sometimes there’s no need to look for new land for a development. DGNB certification awards points for building on disused land, filling gaps between developments or re-using land to make better use of local infrastructure. If a building is erected on land that was previously polluted or contaminated (i.e. a plot is made reusable), this receives a circular economy bonus under the land use criterion.
Using plots sparingly and finding ways to look after land and soil is not just necessary for environmental reasons. Infrastructure costs are rising continuously, so there are also plenty of economic reasons why this makes sense, such as the expense of tapping into local infrastructures and disposing of wastewater. Overall, this also improves the microclimate. The aim of this criterion is therefore to reduce the burden on land when it is used by developers and to encourage as many people as possible to avoid using undeveloped or previously unused land.