Circularity in practice – part 1 – update
Bouwdata
Circularity in practice – part 1 – update
The future belongs to those who digitise, diversify and recycle.
For the latter, BouwData© fell short. So we dove back into the theory to find an answer i.c.w. Laura Denoyelle. With its eyes focused on cost control, agreement scheme AS9 Substances is the outcome of that study.
The starting point is the standard NBN EN ISO 12006-2:2020 Building Construction – Organisation of information about construction works – Part 2: framework for Classification
(ISO 12006-2: 2015).
This provides a framework for the development of classification systems for built environments. In a nutshell, you have construction resources that result in construction results through a construction process.
For the circularity level of a building, we are interested in raw materials. These give a concrete value to the building that is separate from the ‘real estate’ value. This is a single pillar for estimating what a building might be worth in the future, when demolished.
We find these resources in the construction resources branch: product, aid, agent and information. Construction product is further subdivided into raw materials (substances) on the one hand and shapes on the other. See figure 1 below.

Above the raw materials in the diagram we find the life cycle cost: this gives the full cost in the life cycle of a building. When the building is worn out, a new cycle starts in which it is decided what will happen to the site. Here, the basic raw materials that are still present are also part of the starting capital.
The BB-SfB1 1990 table 3 provides a concrete interpretation for these raw materials. However, the SfB is not the only possible interpretation of NBN EN ISO 12006-2. CCS, Uniclass and Omniclass are also interpretations of this. It is therefore logical to take a look at what they have come up with as a classification for the construction resource ‘product’:
- CCS2 omits this and offers no answer
- Omniclass3 offers table 41 with 256 lines across 6 levels. Much more comprehensive, therefore, than Table 3 of the SfB. The question is whether this is also desirable in practice given the desire to lose as little time as possible filling in that extra parameter in the model to determine the circularity level. The more choice, the more difficult the filling in.
- Uniclass4 offers table Pr with 6764 lines across 4 levels. Pr stands for Product and is more suitable for organising a Wallmart for building materials, second-hand or otherwise. For people aspiring to this, best to put this table alongside the Etim classification to see what works most practically. But for us, this table misses the mark.
1 Originates from the Swedish committee Samarbetskommittén för Byggnadsfragor which loosely translated means the Joint Working Committee on Construction Problems, dates from 1947 but is still of very great relevance in the digitisation of the construction industry.
2 Cuneco Classification Systems, Danish
3 Published by CSI and American
4 Published by NBS and British
Raw materials integrated in BouwData©
In the BouwData Excel AS9 Substances, Table 3 of the BB-SfB 1990, Table 41 of Omniclass and Table Pr of Uniclass are contained, each on a separate tab provided with the necessary groupings and autofilter to quickly look things up.
All things considered, good old SfB seems the most practical to start from. But this remains an academic piece of work that still requires some ‘twists & turns’ to be workable in practice. Within BouwData©, only 10 main categories are therefore retained:
- a juxtaposition of raw materials
this can be used if the product clearly consists of several raw materials e.g. a metal stud wall clad with plasterboard and filled with rock wool.
In the model, this forms a single entity and it requires too much work to model each of these three components separately and assign them their own raw material parameter. Therefore, for convenience sake, ‘a’ is used here.
However, be aware that when using such a model, the volume with parameter ‘a’ will end up in the ‘unknown’ category and thus have a negative impact on the building’s circularity score.
If funding depends on the latter, it is still worth considering something that allows the three components to each be given one of the codes below.
- e natural stone
modellers who want to can further refine here to:
- e1 igneous rock e.g. granite
- e2 marble
- e3 limestone excluding marble e.g. bluestone
- e4 sandstone
- e5 slate
- e9 raw materials of a type e not mentioned above
- f made with binder
AS9 Substances also has a further subdivision here
- g clay – idem
- h metal – idem
- i wood – idem
- j organic substances – idem
- m inorganic substances – idem
- n rubber, plastic, bitumen – idem
- o glass – idem
Integration of demolition – EURAL – in BouwData©
However, there is another side of the coin. Any raw material ‘stored’ in a building will sooner or later become demolition material. And the latter has already been addressed by European Union member states and the European Waste List (EURAL) has been created. This list contains around 800 different types of waste, some of them classified accoroding to the industry in which the waste is released. Chapter 17 deals with Construction and demolition waste and has further main classification 1:
- 17 01 Concrete, bricks 2, tiles and ceramics
- 17 02 Wood, glass and plastic
- 17 03 Bituminous mixtures, coal tar and tarred products
- 17 04 Metal (including their alloys)
- 17 05 Soil (incl excavated soil from contaminated sites), stones and dredging spoil
- 17 06 Insulating materials and asbestos-containing construction materials
- 17 08 Gypsum based construction materials
- 17 09 Other costruction and demolition waste
1 Further subdivision is in the relevant tab in the AS9 Substances
2 I.e. bricks
In the Building Information Management execution plan, it is therefore best to choose whether to classify materials according to table 3 of the BB-SfB or according to the EURAL code. Or one may wish to know both.
The complete Excel workbook with the BouwData AS9 list with both classifications side by side and original classifications in separate tabs is available free of charge by sending an e-mail to info@bouwdata.net.

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