We interviewed Richard Kelly, Operations Director for buildingSMART International, to get his take on the Design for Manufacture and Assembly (DfMA) trend in AEC Industry.
The concept of DfMA was developed in the 1970s as a structured way of making product development more efficient.
Today, however, DfMA is one more manufacturing concept that is transforming the efficiency with which buildings are brought to market.
While it’s not a new concept, it is gaining greater acceptance as new technology allows for improved communication among AEC practitioners.
When applying this concept to the AEC industry, DfMA is about taking a holistic view of a building to determine the best way of making it.
It has as its goal the efficient production of a high-quality, cost-effective facility that, despite its mass production of certain processes, still provides the variety the client desires.
To understand how this is accomplished, it’s important to understand the two main components of this approach.
Breaking Down the Approach
Design for Manufacturing Assembly refers to the creation of manufacturing processes that are capable of producing a desired product. This is not about creating the highest-quality product — it’s about creating the means to cost-effectively and efficiently create the highest-quality product.
According to Kelly, DfMA aims to create a series of components that can be put together in various ways, thereby providing both efficiency and variety in product creation. It’s a process well-suited for construction because it’s geared toward quickly producing a variety of parts.
In this approach, one might see:
- Component sharing, swapping or mixing to make distinctly different products.
- Common interfaces that allow different components to easily fit together.
- A “cut to length” type modularity where variety can be created by a few different sizes.
- A busbar-type of modularity where different components fit into a common framework.
Together, DfMA encourages collaboration among the trades to manage interfaces, eliminate clashes, and more effectively capitalize on innovative offsite practices. DfMA can be made more efficient still when combined with a Lean approach that reduces wasteful practices.
Benefits of a DfMA Approach
Through DfMA, contractors can identify when to take work offsite to put it into a Lean factory environment and how to achieve better flow for the elements that are on site. This leads to various improvements that each contribute to reduced costs and tighter overall scheduling.
Among the benefits are:
- More predictable installation. A DfMA approach also looks to eliminate components, since more parts means greater potential for assembly problems. It also requires tolerances among various trades to be agreed upon in the early design stage. Therefore when components do arrive at the job site, they all interface correctly.
- Higher quality components. Since much of the project assembly is done in a clean factory environment, the end product can be of higher quality than what’s produced onsite. Also there is opportunity for better quality materials which, as a piece part might be more expensive, but overall the costs are saved through less construction time and reduced lifetime maintenance.
- Improved worksite safety. This prefabrication focus means that fewer trades are required onsite, and the site aspects are better illustrated and the workspace is more predictable, which leads to improvements in both safety and logistics.
Benefits also carry over to the building’s operation and maintenance, including:
- This holistic design approach gives consideration to providing easy-access for maintenance or end-of-life component replacement.
- Because the DfMA approach relies on the use of modeling tools it is simple to pass building information on to the owner and operations team. Owners then have at their disposal information guiding decisions on preventive maintenance and predictable insight into the asset’s performance through its life.
The Need for Early DfMA Buy-In
To effectively use a DfMA strategy, all parties must contractually agree to this approach at the onset of the project. Such was the case in the design of Heathrow Airport Terminal 5C, a DfMA project cited by Kelly.
The owner wanted to improve worksite safety, but the DfMA approach demonstrated cost and quality benefits for the terminal construction as well.
Aspects of the facility were designed as a combination of flat-pack and volumetric solutions. Tolerances were taken out of ground level and component parts were made in the factory on an optimized flow line then delivered to the site as needed. The aircraft to terminal nodes were assembled by six onsite workers at a rate of two weeks for each of the 12 stands.
Approximately 33,000 hours of labor were removed from the site.
Overall, the delivery schedule was shortened by 75 percent, which led to approximately £2.5 million ($3.6 million USD) in operational savings.
Factors Preventing DfMA Adoption
Elements of this approach have been used in AEC for decades, but they have not yet been cohesively linked, nor is it routine for each of these elements to be used in the design, build and operation of a facility.
According to buildingSMART, one of the chief elements holding back more widespread adoption of DfMA is the lack of open, shareable data. Numerous companies work on any given project, but without a common platform or data standard (i.e. Industry Foundation Class, IFC) for sharing information, each trade is working in a silo. There is no sharing of tolerances and other data that can improve a project’s assembly and future maintenance.
Forward-thinking designers, contractors and subcontractors — as well as owners who encourage preferred partners to adopt the technology necessary to succeed in a DfMA approach — stand to gain significant benefits.
In addition to reduced schedules and costs, and higher levels of job site safety, the client stands to gain a documented process that describes how to maintain the facility and dispose of it at the end of its life.