Polyisocyanurate Roof Insulation R Value

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.

Polyisocyanurate roof insulation r value.

Acfoam polyiso roof insulation. 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. Polyiso has a high r value per inch compared to other insulation products. Polyiso insulation thickness r value chart.

Jm revised lttr values jm suggests that design professionals use 5 7 r inchas a design specification for its foam products. 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 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. 3 rsi is the metric expression of r value m 2 k w.

Tapered polyiso minimizes the negative effects of ponding water and extends the service life of a roof. Jm is proud to be a pima member and have its product third party certified under the pima quality mark program. Carlisle s tapered insulation helps promote rooftop drainage while providing excellent insulating value. 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.

In addition to testing at a 75 f mean reference temperature which is typical for r value labeling. Understanding r value thursday december 13 2018 what does r value mean. During 2009 nrca conducted limited r value testing of uninstalled polyisocyanurate insulation samples ranging in ages from 4 to 13 months. Excellent lttr value compared to any other fm class 1 rated products of equivalent thickness.