The ASTM C1289 Standard Specification for Faced Rigid Cellular Polyisocyanurate Thermal Insulation Board (ASTM C1289-11) has been updated and features important improvements regarding the prediction of long-term thermal resistance value for a variety of polyiso insulation boards. The PIMA QualityMark program, the only third-party program for the certification of the thermal value of polyiso insulation, will begin reporting Long Term Thermal Resistance (LTTR) values in accordance with ASTM C1289-11 on Jan. 1, 2014.
The PIMA QualityMark certification program is a voluntary program that allows polyiso manufacturers to obtain independent, third-party certification for the LTTR values of their polyiso insulation products. Polyiso is the only insulation to be certified by this program for its LTTR value. The program was developed by Washington, D.C.-based PIMA and is administered by FM Global, Johnston, R.I.
To participate in PIMA’s QualityMark certification program, a Class 1 roof is suggested to have a design R-value of 5.7 per inch. PIMA member manufacturers will publish updated R-values for their polyiso products later this year. Polyiso is unique in that the R-value increases with the thickness of the foam, so 3 inches of polyiso has a higher R-value per inch than 2 inches.
“Since its founding, PIMA has been very active in the harmonization of relevant standards, including ASTM and CAN/ ULC, in an effort to provide greater continuity in the reporting of polyiso roof insulation thermal values throughout North America. That is why the association implemented the industry-wide Quality-Mark certified R-value program for rigid polyiso roof insulation in 2004,” says Jared Blum, president, PIMA. “The update to this standard provides more data to aid in the prediction of long-term thermal performance of polyiso insulation.”
To provide a comprehensive approach to predicting long-term R-value throughout North America, the updated ASTM C1289-11 standard now incorporates two test methods, ASTM C1303-11 and CAN/ULC-S770-09, which offer a similar approach to predicting the long-term thermal performance for foam insulation materials that exhibit air and blowing agent diffusion or aging over time. Both test methods employ a technique called “slicing and scaling” to accelerate this aging process and provide an accurate and consistent prediction of product R-value after five years, which is equivalent to a time-weighted thermal design R-value for 15 years. The update to ASTM C1289-11 in no way impacts polyiso’s physical properties.