Last edited 24 Mar 2021

Main author

BRE Buzz Researcher Website

Circular building assessment prototype


[edit] Introduction

BIM-CBA-fig 1 768x432.jpg
Figure 1: Vision of CBA information flow to undertake the assessment on the online portal
This article summarises the ongoing technical developments of a user-friendly and pragmatic tool for assessing circularity in buildings with varying levels of data and design stage.

[edit] A BIM-based solution for resource productivitydevelopment, validation and trial

BAMB Circular Building Assessment, referred as CBA, is a methodology that compares and assesses product and material resource flows during the life time of a built asset and beyond. This method is being developed into a prototype online platform/tool that can quantify and compare design approaches, focussing on the difference between ‘business as usual’ versus circular building scenarios. These include reusing from the previous built environment, designing for future reuse via reversible building design, and the potential to transform, highlighting the corresponding environmental and economic net benefits.

The CBA methodology has been set out consistently to enable exchanging of attributes based on ISO 16739 [Industry Foundation Classes, IFC] which is the backbone for communicating BIM data. The data acquisition aspect of CBA is crucial to reducing the amount of data that needs to be input by the user (Figure 1 above illustrates how information will be sourced to do the CBA assessment).

The platform will allow users to upload a COBie or information exchange file generated from authoring software (e.g. Revit, ArchiCAD, Sketchup) used to create a BIM model. The platform can then automatically extract from the model: quantity data input by the user, relevant bills of quantities and material data for the assessment. Where there are data gaps, a series of webservices are being developed to pre-populate information, such as material density and reversibility of connections, which the user can review and edit.

Fig 2 BIM-revit.jpg
Figure 2. Screenshot of Revit object with assigned properties. Human readable descriptions for each property are brought through and if supported by the software can be displayed

The data input (BAMB information requirements) needed to undertake the CBA assessment will then be converted into a series of BAMB templates using BRE’s data Templater software (See This schema communicates the additional BAMB properties in a neutral way in order to extend any software that allows ‘extensions to its parameters’ (see Figure 2 above and Figure 3 below).

Fig 3 BIM-sketchup.jpg
Figure 3. Screenshot showing Sketchup object with assigned properties. Applied via the Sketchup plugin toolbar

The BAMB Information Requirements provide a placeholder within the BIM model for data to be stored against them. This is also accompanied with relevant mapping files that enables the export to IFC[1] and COBie[2] or a tailored implementation the project refers to as ‘BAMBie[3]’ that details more on the material level than a typical COBie exchange might provide. The platform will then use this information exchange format to recreate a BAMB data model on the platform automatically and then perform CBA calculations. (See Figures 4 and Figure 5 at the end of this article for comparison of results for one of the pilot projects).

The CBA user platform and core elements of the overall system are currently undergoing validation using the BAMB pilot projects. Ultimately, the CBA platform will provide a truly practical circular building evaluation approach, starting at early design stages and expanding with granularity of information as a project progresses into detailed delivery phases. Through this, BAMB is developing a proof of concept that clearly demonstrates the ability to develop multiple design options and assess rapidly in a semi-automated environment, using data from Building Information Modelling, where available, or providing a foundation of assumed data where it is not.

Fig 4 BIM CBA-1024x699.jpg
Figure 4. Illustration of Building 16 circular building assessment reports on the CBA web platform
Fig 5 BIM CBA-1024x895.jpg
Figure 5. Illustration of embodied carbon comparison between two different wall scenarios.

[edit] References

[1] IFC – Industry Foundation Classes – (IFC) data model is intended to describe building and construction industry data. It is a platform neutral, open file format specification that is not controlled by a single vendor or group of vendors.

[2] Construction Operations Building Information Exchange (COBie) is an international standard relating to managed asset information including space and equipment.

[3] BAMBie – Buildings as Material Banks Information Exchange – a way for users to communicate the information required for the CBA. Similar to COBie, it is written in a machine-readable language that has advantages for web-platform interaction.

[edit] About this article

This article was written by Julia Barnard, Advisory, BAMB, BIM, CBA, Circular Building Assessment, Circular Economy. It was previously published on the BRE Buzz website and can be accessed here.

More articles by BRE Buzz on this website here.

[edit] Related articles on Designing Buildings Wiki

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