Hempcrete Passes 1-Hour ASTM Fire Test

sustainable constructionBuilding regulationsInnovation

Jul 15

*A hemp lime (hempcrete) wall is ready to be tested at the Intertek facility in York, PA. Photo courtesy of Americhanvre*

By Jean Lotus

US Army-funded researchers in Pennsylvania achieved a one-hour fire resistance rating for a spray-applied hemplime (“hempcrete”) wall test panel in early July, moving hempcrete closer to acceptance as a US building material.

A spray-applied hempcrete wall was subjected to a blistering 1,700-degree Fahrenheit heat test as part of the ASTM E119 fire resistance testing for building materials at York, PA-based Intertek. The 12-inch wide full-scale wall sample was created by PA-based Americhanvre Cast Hemp with the Ereasy Spray Applied system.

“It was breathtaking to observe, in real time,” said Americhanvre co-owner Cameron McIntosh, in a press release. McIntosh observed the tests from the Intertek control room. “That face never rose a single degree above ambient temperature, despite the intense heat on the other side.”

“The execution of this test will serve to unlock the commercial potential for the Ereasy hempcrete system in the U.S. construction market as we now have definitive proof of the material’s performance,” McIntosh added.

A total of four panels will be tested, each created with an internal bracing frame according to the details in the 2024 International Residential Code Appendix BL, which McIntosh co-authored.

Sign up for our free newsletter

*Singed but not burned, the hempcrete wall was hosed down after one side was exposed to 1,700 degree heat for 60 minutes. Photo courtesy of Americhanvre.*

Americhanvre

Texas Healthy Homes

South Bend Industrial Hemp

Sativa Building Systems

Whitefield Hemp Partners

Hemp Traders

Hillside Center for Sustainable Living

Gradek Contracting & Designs

The testing research was part of a US Army $1.9 Million Phase II SBIR grant awarded to Americhanvre this year. Engineering support was provided by Berkeley, CA-based Verdant Structural Engineers.

Other companies have also completed ASTM fire resistance tests, including Perennial Building in Sisters OR, which completed an ASTM E119 fire test on a smaller wall sample last year. Idaho-base Hempitecture, Inc. completed ASTM E84 Fire resistance tests in 2020.

Click here to go to our FREE online community.

*Americhanvre hempcrete panel before testing. Photo courtesy of Americhanvre*

Testing Hempcrete for R-Value

Even though hemp-lime insulation has been tested and approved for construction in the EU, it’s necessary to repeat some of the testing in the United States to move the industry forward with a new insulation material.

Last year, Amerchanvre completed ASTM C518 R-Value testing with a lab in Tennessee. Hempcrete was found to have an R Value of about 2.2 per inch, according to the tests.

The FTC requires that R-values of insulation be disclosed as tested by a range of ASTM tests, including C-518.

“This test is required by the FTC, but not necessarily by the local code office,” McIntosh told HempBuild Mag last year.

Homeland Hempcrete

HempStone

Complete Hemp Processing

Verdant Structural Engineers

*Cameron McIntosh, co-owner with Melissa McIntosh of Americhanvre Cast Hemp. Photo courtesy of Americhanvre*

McIntosh stressed that these tests are designed to apply to all hempcrete products, even though the tests were specific to Ereasy sprayed hempcrete, which uses a proprietary binder.

“We predict these [ASTM test] results will have a positive impact for the entire industry,” McIntosh said. The one-hour fire test is “confirmation of a widely held belief in the hemp building community – the impressive fire resistance characteristics of a well-built hempcrete home,” McIntosh added.