Jm suggests that design professionals use 5 7 r inch as a design specification for its foam products.
Polyiso roof insulation r value per inch.
Building science corporation bsc and others have been examining this difference.
Dated its r value recommendations for polyisocyanurate insulation used in roof systems.
Polyiso has a high r value per inch compared to other insulation products.
Jm revised lttr values.
However labeled r value differs from in service r value for many insulations.
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.
Jm is proud to be a pima member and have its product third party certified under the pima quality mark program.
Let s use the r value of iko s polyiso insulation enerfoil tm as an example.
It has one of the highest r values per inch of thickness among common insulations.
R value chart for enerfoil tm rigid foam faced insulation conditioned per atsm c1289 test method astm c518 1 2.
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.
Benefits of energyguard polyiso roof insulation include.
Excellent lttr value compared to any other fm class 1 rated products of equivalent thickness.
Polyiso still remains the highest r value per inch of any available insulation.
Membrane roof systems 2015 nrca had recommended designers use in service r values of 5 0 per inch thickness in predominant.