Standardization News

In construction, occupant safety is paramount. As a result, the industry is heavily regulated and slow to adopt new technologies — a reflection of the fact that too often those regulations have come about because of tragedy. Given this reality, using new technology to help solve problems such as housing scarcity can be a daunting task. 

To address this situation, Mighty Buildings is taking a collaborative approach in using new technology. The company is helping to address the lack of productivity and sustainability in the built environment while welcoming the challenge of clearing the high bar necessary to demonstrate code compliance. Using light stone material (LSM) — a proprietary ultraviolet (UV)-curable thermoset composite printed with the company’s proprietary 3D printing technology — Mighty Buildings is the first company in the world to deliver residential units using UL-certified, 3D-printed components. These residential units are the first to be approved under California’s Factory Built Housing program to incorporate 3D printing. Three years were spent identifying the pathway to that approval and then moving down that road, one paved with ASTM International standards.

In helping UL to develop the world’s first standard specific to 3D-printed construction (UL 3401), Mighty Buildings products went through rigorous testing. That testing took advantage of a variety of existing ASTM standards developed for polymeric materials and traditional construction materials/assemblies. 

A small sample of the standards/tests used to demonstrate code compliance under the Alternative Means and Materials of the California Building Standards Code include:

• Test method for thermal performance of building materials and envelope assemblies by means of a hot box apparatus (C1363);
• Test method for determining rate of air leakage through exterior windows, skylights, curtain walls, and doors under specified pressure differences across the specimen (E283/E283M);
• Test method for water penetration of exterior windows, skylights, doors, and curtain walls by uniform static air pressure difference (E331);
• Test method for wind load resistance of rigid plastic siding (D5206);
• Test methods of conducting strength tests of panels for building construction (E72);
• Test method for structural performance of exterior windows, doors, skylights, and curtain walls by uniform static air pressure difference (E330);
• Practice for static load test for shear resistance of framed walls for buildings (E564);
• Test method for density of liquid coatings, inks, and related products (D1475);
• Test method for steady-state thermal transmission properties by means of the heat flow meter apparatus (C518);
• Test methods for flexural properties of unreinforced and reinforced plastics and electrical insulating materials (D790);
• Test method for shear properties of composite materials by the v-notched beam method (D5379/D5379M); and
• Test method for tensile properties of plastics (D638).

By taking advantage of the work reflected in these existing standards, Mighty Buildings has been able to show to California code officials (as well as other countries and U.S. states where expansion is being discussed) that their novel material, and the resulting printed components made with it, fully comply (and in many cases exceed) building-code requirements. Using existing standards has helped accelerate bringing this novel technology to the market — and has enabled the continued expansion of use cases for 3D-printed material as additional testing is done. This has allowed the company to deliver accessory dwelling units (ADUs) — sometimes referred to as granny flats/in-law units/backyard apartments — to homeowners since 2020. This work is also paving the way for the world’s first “zero net energy” community built with 3D printing. The community will be a combination of single-family homes (SFHs) and ADUs that will break ground in early 2022 in Southern California’s Coachella Valley.

The first units delivered using LSM are Mighty Mods — volumetric modules that can allow a site to go from green field to completion in a month once permits are in hand. The Mighty House product line comprises units that can be manufactured either as ADUs or SFHs. The line is currently undergoing code review as a part of California’s Factory Built Housing program based on rigorous testing to ASTM standards. And the line uses the Mighty Kit System, a 3D-printed panel system manufactured in our facility and then delivered and assembled on site. The system allows for customizable floor plans for developers and builders seeking to accelerate the availability of housing despite limited resources.

Without ASTM and the breadth of its standards, it would be nearly impossible to demonstrate the safety of such a revolutionary technology to building officials. This is particularly true in California, which has some of the most stringent building, energy, and environmental regulations in the world. 

Mighty Buildings’ engagement with standards doesn’t end with the use of existing standards. Given the incredible promise of 3D printing in construction, it is imperative that a standards scheme be put in place to ensure the safety of these technologies while also providing the flexibility needed for continued innovation. To do that, company staff members are helping to ensure that developed standards will provide a pathway for other novel applications of additive manufacturing (AM) in the built environment. Sam Ruben, chief sustainability officer and co-founder at Mighty Buildings, serves as chair of ASTM’s AM construction section (F42.07.07). Alexey Dubov, chief operating officer and co-founder, Mighty Buildings, serves on the AM technologies committee (F42) and on the International Organization for Standardization (ISO)/ASTM Joint Group 80, which is similarly developing standards for the use of AM in construction.

Mighty Buildings is proud that staffers are a part of ASTM and are working with its membership to bring these new standards to life while also leveraging existing standards. The company believes its approach will provide a pathway for innovating in a traditionally conservative industry. ■

Company Snapshot

• Mighty Buildings Inc.
• Company Headquarters: Oakland, California
• Description: Mighty Buildings is an innovative construction technology company based in Oakland, California, that is changing the construction industry by creating more sustainable, high-quality homes using 3D-printing technology, advanced materials, and robotic automation.
• Number of staff: 160+
• Number of staff who are ASTM members: 3
• Trading Area: Currently delivering in California but in the process of expanding to the rest of the United States and the world.