Hempcrete Fire Performance — References & Testing
Hemp-lime is non-combustible by composition. The lime binder is mineral and does not contribute fuel; hemp hurd inside the matrix is encapsulated by lime.
ASTM E84 Surface Burning
Independent ASTM E84 tests on hemp-lime walls have reported Class A flame spread and smoke development ratings. Class A is the highest non-combustible interior finish classification recognized by U.S. building codes.
Class A flame spread rating (ASTM E84) Context
Multi-hour fire endurance results for hemp-lime walls have been documented in European testing under EN 13501-1 and equivalents. Listed assemblies vary by thickness, density, and finish. Specify by tested assembly for code submittals.
What this means in practice
Hempcrete and GaiaCrete™ do not require added chemical flame retardants. No off-gassing of halogenated fire chemistry. Specifications and stamped engineering for your project are available on consultation.
See also: Proof hub · GaiaCrete™ · Hempcrete Insulation