If we translate this approach for Sustainable building, a first observation is that permission for constructing a building should be related to the question: are there resources available for construction?
A next observation is that when a building is ready, it no longer is a solitary object, but part of the Building Stock, and should be managed as such. It has become a resource in itself (with products stockpiled in a for humans useful form), and is part of the "stony forest" that provides shelter for shelter demanding functions. Decisions to demolition or change are not single responsibilities, but have become part of total stock management.
Application of the before described cycle steps for the building sector implies that the total stock of resources, including those reformed for useful service, should be basis for a sustainable resource approach regarding building and construction. Only within that system things can be changed, demolished or re-used. resources
The new cycle no longer starts with the availability of some kind of ore, but with the required functional units. In terms of building and construction, its space provision that is the key, and this can eventually be virtual space, not necessarily physical. To have a meeting not always a building is required. If the function however is physically provided, it should have a very long lifetime, with re-use at the highest level: as a building. . [1]
Only if this is absolutely impossible, for reasons to be specified, it can be dismantled for re-use at the highest level: f.i. providing a window function, therefore as a windowframe, or providing a separation function: concrete slabs as concrete slabs as has been demonstrated in Berlin. [2] (Berlin, 2006)
When quality of these partial functions prevents such, only then they can be treated as materials again, to be upgraded to new products to serve new functions. [3]
Buildings that will be newly constructed should at first be compiled from [2] and [3].
Another possible source in this stage could be residues from other industries, to be upgraded to building products. [4]
Of course this will not be enough in many practical situations, by this time primary materials can be supplemented to the cycle, coming from renewable resources ( within the time constraints explained above). [5]
It is obvious that there is only to speak of a closed cycle if resources in step 6 are avoided, that consists of non renewable resources additions to the cycle. If these resources are used, total stock will decrease. Which can of course be allowed for some time, in a normal situation, when followed by a time in which stocks can be restored.
Ill 2
From this model its obvious that this will require another approach in managing and assessing and classification. Its about measuring the performance towards a contribution in a closed cycle approach, or the deflection of this in a certain activity or function.
It should be measured how each element in the chain improves itself in the direction of closing the cycle (conditions). It implies that each step needs a separate evaluation:
- production of products can and should be measured by itself.
- In compiling buildings in providing functions, the performance of products is not at stake, only the efficiency of the compilation and choices made to do so. This co-insides better with the responsibilities of the different stakeholders in the process. The architect has no influence how efficient a brick is produced. He is responsible for making a construction choice, ( bricks, concrete, wood) and should be assessed as such.
- The same for the management of the building stock, which is another responsibility, that of public services like municipalities, governments housing associations etc, and they should be measured towards their closed cycle responsibility in this respect.
- Transport , both the means and the distances, require there own approach and assessment.
- Mining of resources can be possibly combined with measuring the performance of (non renewable) products manufacturing, as coming from outside the closed cycle. This has to be studied while developing assessment methods.
There is another advantage not to evaluate the whole chain in one process. If we assess a building, incorporating everything from extraction to waste incineration, no-one involved in the whole chain of activities can see his or hers contribution, let alone see the (subjective improvement. And
Ill 3
It should be clear that the prime responsibility for the overall performance is with stock management, and the stakeholders involved. In different societies in different phases of development, the priorities will differ, however the trend in approach will be the same.
To summarize: The overall stock management responsibility is with national governments, setting the borders between which the building sector can operate. Here also lies a primate to develop alternatives: the non materialised way of providing functions: Information technology for instance can create virtual offices, reducing the need for real construction. The role It can play in this field has been studied in the SANE project [Fernando, 2003]
The responsibilities for re-use are at municipal level to be organised and assessed. Production of elements responsibility is with industry, guided by the borders set by overall stock management, and compiling buildings is the responsibility of construction partners.
The 'traditional' Dutch approach, the Trias Ecologica, which states that step 1 is reduction, step 2 is use renewables and step 3 is use remaining need as efficient as possible, is in fact a practical tool to implement each separate part of the closed cycle approach. Originally used for energyconcepts for new buildings, but applying for all resources and or providing services approaches.
At Wageningen university we have developed a practical approach to deal with the right part of the cycle: to capture , convert and re-enter Urban resources in the cycle. Not only for construction, but from a broad point of view in municipal environmental management. This approach is called Urban Harvesting.(Rovers,R,2007) see UH section.
Separate work is carried out for detailing the approach and assessment of new buildings, following the above described principles. In the 'building section this will be highlighted.
