Polyisocyanurate Roof Insulation R Value

Understanding r value thursday december 13 2018 what does r value mean.

Polyisocyanurate roof insulation r value.

Test results showed r values less than the products established lttr values. Benefits of energyguard polyiso roof insulation include. Measuring the r value of polyiso roof insulation at the website of pima polyisocyanurate insulation manufacturers association discusses long term thermal resistance lttr the astm standards underlying the r values for polyisocyanurate insulation and provides r values for various thicknesses of polyiso which increases in r value per inch as total thickness of the installation increases. Excellent lttr value compared to any other fm class 1 rated products of equivalent thickness.

Jm revised lttr values jm suggests that design professionals use 5 7 r inchas a design specification for its foam products. Jm is proud to be a pima member and have its product third party certified under the pima quality mark program. To minimize the effects of thermal bridging atlas strongly recommends the use of multiple layers when the total desired or specified r value requires an insulation thickness greater than 2 7 thick. Polyiso still remains the highest r value per inch of any available insulation.

Tapered polyiso minimizes the negative effects of ponding water and extends the service life of a roof. Polyiso has a high r value per inch compared to other insulation products. Polyiso is unique in that the r value increases with the thickness of the foam so three inches of polyiso has a higher r value per inch than two inches. Acfoam polyiso roof insulation.

Fm approved subject to the conditions of approval as a roof insulation when installed as shown in the current edition of the factory mutual research approvals guide. 3 rsi is the metric expression of r value m 2 k w. A higher r value means that the insulation will do a better job of holding in conditioned air whether that s heat in the winter or cool air in the summer. In addition to testing at a 75 f mean reference temperature which is typical for r value labeling.