LTTR is the most advanced, scientifically supported method of predicting the Long-Term Thermal Resistance of polyisocyanurate insulation products, such as Atlas Roofing's ACFoam®.

Building codes require a structure to meet certain R-values to achieve a specific level of efficiency. The climate zone plays a big role in determining what the minimum R-value has to be for a specific region.

This standard represents the minimum required prescriptive R-value (resistance to heat flow) for roof and wall insulation levels. The R-value requirements for this standard were recently increased by 33% for climate zones 2 thru 8.

Polyiso insulation is the only foam plastic insulation that can be used in almost all types of roof systems without the need for a thermal barrier. No other foam plastic insulation has the perfect combination of features so important for long-term performance.

All Atlas ACFoam® polyiso insulations are QualityMark^cm certified, giving consumers an easy way to identify quality products that meet or exceed listed LTTR-values. FM Approvals has approved the use of ACFoam® as a component in Class 1 insulated roof deck construction.

Stay up to date with what's going on with the building industry and everything greenbuild related such as ASHRAE, LTTR, Climate Zones and R-value Standards. Industry news is updated frequently, so check back often.