In fulfilling our ambitions to turn the linear economy into a circular one, we come across new and innovative concepts that challenge our current way of thinking and provide us with tools to look at the world in ways not considered before. In the construction sector, there is of course great interest in the reuse and recycling of materials. However, these materials first need to be separated from their original application. This is where the concept of detachability comes in.

Detachability

The degree of detachability determines how easy it is to remove a building’s component, either for maintenance or for reuse. It is important to record information on this aspect, because a component that cannot be detached, cannot be reused and, therefore, is not circular. Measuring the degree to which a building can be deconstructed at the end of its life can also provide information about the ease with which the building can be maintained during its active life. This is of interest to the owner, manager and others responsible for the building’s ongoing maintenance.

Within the Netherlands, detachability has been formalized in research conducted by the Dutch Green Building Council (DGBC), BREEAM-NL, and a group of their partners. The latest version of this research (at the time of writing) can be accessed via this link. The text can be rather dense, so the basic concept is summarised below.

How to measure?

To understand how the detachability index works, it helps to imagine the building as a sum of its parts, as small Lego pieces working together to form a functioning whole. The detachability index refers to these small parts as products or elements, with products being defined as the individual components that arrive at the building site and are subsequently integrated into the building. Elements are the components that contain products but arrive at the site in one piece, such as a heating unit, or a prefab facade that comes with its own insulation.

First, the detachability of a product or element is defined according to its score on a scale from 0.00 to 1.00, based on four distinct factors: Connection Type, Connection Accessibility, Independence, and Geometry. Each factor is explained below:

1. Connection type represents the way in which two parts of a product or element are connected to each other. For the connection type, a score of 1.00 indicates a dry connection where a component can very easily be removed or clicked into place. A slightly lower score is assigned if added parts are required, such as bolts and nuts, and even lower scores belong to a more direct connection to a structural element, established with a pin or nail, for example. The lowest possible score relates to chemical connections such as adhesives or cement.
2. Connection accessibility describes how easily a connection can be reached. A perfect score of 1.00 indicates that the connection is unobstructed and freely accessible, such as a light fitting within easy reach. The score is lower if additional action is needed, such as having to open a panel. The score is lowered even further if subsequent repairs are required. The least favourable scenario is when a component cannot be accessed without causing irreparable damage to surrounding areas. For example, in the case of a beautiful custom-made sink that has been poured and cast on site with great craftmanship, but whose drain is subsequently inaccessible behind the poured concrete.
3. The factor of independence indicates the extent to which a component is integrated into other products or elements within a given structure. If removal of the component has no impact on other components, products or elements, this results in a perfect score.
4. Geometry refers to the shape of the component. This score can be drastically reduced if the shape of its edges cause the component to become obstructed by or overlap other components, products or elements.

The sum of the scores on the 4 factors assigned to each element is used to calculate a weighted average that then indicates the final detachability score for the building as a whole.

Reliable measurement data

Does that sound rather complex and a lot of work? Then you will be pleased to know that Madaster’s Detachability tool has been approved by BREEAM-NL and the DGBC as a reliable calculation tool for detachability. This tool will help to make the process much simpler. A link to the announcement (in Dutch) can be found here.

It is good to see that there are powerful initiatives to make large steps towards a circular economy. Steps that offer us new and innovative perspectives on achieving circularity. BREEAM-NL and the DGBC are pioneers when it comes to detachability, and we are looking forward to seeing others following in their footsteps — all in their respective fields.

Ehsan Rahimi

Product Manager Madaster