NBC of Canada Adopts Updated Standard for Measuring LTTR of Polyiso Products
BETHESDA, Md. — On Oct.31, 2013, the National Building Code (NBC) of Canada adopted the most recent version of CAN/ULC-S704-11, the standard specification for polyiso in Canada, which references the test method CAN/ULC-S770-09 for determining the long-term thermal resistance (LTTR) of polyiso foam insulation. This adoption brings consistency to the test methods used for measuring LTTR in Canada and the United States.
In the United States, polyiso manufacturers use the ASTM C1289 standard (ASTM C1289 Standard Specification for Faced Rigid Cellular Polyisocyanurate Thermal Insulation Board) to predict the long-term thermal resistance R-value for a variety of polyiso insulation boards. ASTM C1289 includes the CAN/ULC-S770-09 and ASTM C1303-12, another test method used for LTTR.