Meeting the Insulation Requirements of the Building Envelope with Polyurethane and Polyisocyanurate Foam

The use of insulating products in the building envelope is defined by many criteria. The specified R-value or k-factor for the structure is an essential component of most specifications. The industry has traditionally reported the R-value measured at a mean temperature of 75°F for use to calculate insulation requirements for the building envelope. With improvements in instrumentation, it is now possible to specify insulation based upon the actual use temperatures for a given building or region. This paper compares the performance of insulating products over a variety of mean temperature ranges including a discussion of measurement methods.