As part of that standard the products must meet r value requirements presented as long term thermal resistance lttr.
Polyisocyanurate insulation r value aged.
The results also are somewhat lower than the results at 25 f 40 f 75 f and 110 f mean test tem peratures from nrca s 2009 testing.
Because of this phenomenon the r value of polyisocyanurate insulation is not constant.
Rigid polyisocyanurate thermal insulation board.
The information on this page is based on data considered to be true and accurate based on periodic internal.
Polyiso has a high r value per inch compared to other insulation products.
See also material data sheet msds 1511 or msds 1911.
2 stated thermal resistance values are based upon conditioning requirements and test methodology found in astm c1289 and astm c518 for foil faced polyisocyanurate insulation.
As foam ages over time air and blowing agents diffuse in and out of the foam structure resulting in reduced r value.
In 2005 nrca participated in a limited testing program that showed a majority of polyisocyanurate insulation samples tested one to four years after being manufactured had actual r values less than their lttr values.
The in service aged results were compared with the same insulation tested when it was a new material and it was determined the aged insulation had a significantly reduced r value up to 25 at low mean temperatures compared with the new insulation demonstrating the effects of the initial aging on the material s performance.
The r value rule recognizes that the thermal performance of some insulation materials changes as they age e g.
1 when joints penetrations detailed appropriately.
Mates r value after five years of aging in controlled laboratory conditions.
The r value of polyisocyanurate decreases as some of the gasses in the pores from the manufacturing process diffuse out and are replaced with air.
Many but not all foam insulations or settle e g.
As polyisocyanurate insulation ages further its r value decreases at a slower rate until the gas con.
During late 2014 nrca conducted additional limited r value testing of polyisocyanurate insulation and found r values lower than the current lttr values.
This five year figure corresponds closely to a predicted.
Long term performance and aged r value of polyisocyanurate insulaon march 16 2017 csi chicago chapter.
In the unites states polyiso manufacturers typically report r values for wall insulation products measured on full thickness samples following a 180 day conditioning period at 73 f and 50 relative humidity per astm c1289.
In 2009 nrca conducted r value testing at various.
