The European Commission is in the process of harmonizing construction product standards. One of the reasons that this effort is underway is to, “enable the construction ecosystem’s contribution to meeting climate and sustainability goals and embrace the digital transformation because its competitiveness depends on this.” (European Commission, 2022). A major element of the change to the construction standards is the requirement for building disassembly. Disassembly will contribute to the achievement of the climate and sustainability goals. However, there is no industry-wide practice that can analyze a building from a disassembly perspective.

As Produktif considered this challenge, we became convinced that a solution can be found in the Design for Manufacture and Assembly (DFMA) methodology that is used extensively in the automotive industry (Boothroyd et al., 2010). This methodology is used in the early design stage of automotive sub-assemblies to determine the ease of assembly. Sub-assemblies with a better score or less expensive to make and have higher quality because there are fewer possibilities for errors in production. This methodology can be used in the design stage while sub-assemblies are still in development in the CAD systems, before any parts are fabricated.

Although DFMA was developed for automotive, the principles of assembly are universal in any industry. There are four key principles embedded in the DFMA approach

  1. Fewer parts are easier to assemble than many parts. Make sure each part is a necessary component.
  2. Simplify part handling. Parts that are difficult to handle require extra effort and are more likely to be damaged during handling.
  3. Simplify part positioning. Parts that are hard to place correctly will often be out-of-place requiring rework and repair. Also, they often require expensive tools and jigs to position them correctly.
  4. Streamline securing operation. Each part must be secured in the assembly. Different securing processes (welding) increases overhead costs and can create delays and quality issues.

These principles apply in building construction, as well as automotive. What is more, they apply during both the construction process for a building and the disassembly process.

The DFMA methodology uses a scoring algorithm that determines an ease of assembly score for each part. The sum of those part scores provides an ease of assembly score for the sub-assembly. These scores can be turned into ratios that allow comparison between subassembly design concepts and the score can be compared to a desired standard ratio. Produktif has applied the principles from DFMA to create building construction algorithms.

We have developed two algorithms, one for building assembly during the construction phase and the second for building disassembly when the building is to be renovated or removed from the site. These algorithms can be used by architects and engineers at the time of building design to “score” the design for ease of assembly and ease of disassembly. The scores from competing designs can be compared to select the best approach. In addition, an architect or engineer can use the algorithm to make design tradeoffs that will lead to a better score. Produktif has named this the Design for Assembly and Disassembly methodology and currently has a patent pending on the methodology.

The Design for Assembly algorithm closely parallels that DFMA algorithm in structure, however, the details have been adapted to the construction industry. This includes the modification of the definitions used for determining whether a part adds unique value to the assembly. In addition, the parameters for scoring handling and positioning have been modified to those applicable at a construction worksite. While most of the scoring elements for part securing operations are similar to the DFMA, they have also been simplified to align with tools and techniques used in construction.

The Design for Disassembly algorithm includes a number of considerations that are not present in the assembly process. To begin with, the disassembly techniques had to be identified. Where a technique was similar to an assembly technique (loosening a bolt is similar to tightening a bolt) the scoring was repeated. However, where different techniques were required, new scoring values were established. Another area where new principles had to be identified and scores established were scores form component reuse or disposal. Some components can be immediately reused; they receive the best scores. Some components can be reused after repair, refurbishment or reconfiguration;  they receive moderate scores depending upon the amount of work expected. Some components must by recycled or sent for disposal; they receive the worst scores.

The DFAD methodology can be used evaluate a building’s ease of assembly and disassembly which will directly impact sustainability and climate goals. This analysis can be done at the time the design is still in digital format, when changes can be quickly incorporated. Produktif is ready to work with architects, engineers, regulatory bodies, and manufacturers to provide consulting and training in the use of DFAD.

 

References

Boothroyd, G., Dewhurst, P., & Knight, W. A. (2010). Product design for manufacture and assembly (3rd ed.). CRC Press.

European Commission, (2022, October 22). Questions and answers: Revision of the construction products regulation. https://ec.europa.eu/commission/presscorner/detail/en/QANDA_22_2121

Raymond Sheen