A proposed ASTM International standard is in the works to help engineers better understand how various climates affect water vapor transmission of water-resistant barriers and air barriers (WRB/AB) in building envelopes.

ASTM’s EO6 Performance of Buildings Committee is developing the proposed standard.

Danko Davidovic, ASTM International member and senior building scientist with Huber Engineered Woods, says the proposed standard will explain how WRB/AB functions in various wall and roof assemblies.

“The proposed standard is focused on factors affecting WRB/AB performance, best practices to test, and ways to easily report water vapor transmission characteristics,” says Davidovic. “The standard will be easy to follow and reflect the current best building science practices regarding how water vapor transmission properties of WRB/AB impact moisture transport through wall and roof assemblies.”

Davidovic notes the following potential uses for the proposed standard:

  • Manufacturers will find the proposed standard to be a resource to educate themselves about WRB/AB products’ real-life performance;
  • Regulatory agencies will improve water vapor transmission property requirements for WRB/AB materials and systems in current building codes;
  • Architects, designers and engineering professionals will calibrate the design requirements and specify WRB/AB water vapor transmission properties in their design documents; and
  • Educators will be able to use the proposed standard as a supplemental educational tool in engineering curriculums for building envelopes and industry training programs on the best WRB/AB products for a particular project.