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A question of accuracy

Professional Roofing



polyisocyanurate; insulation; lttr; r-value; aging

In January, North American polyisocyanurate insulation manufacturers implemented updated procedures for testing and reporting the insulation’s long-term thermal resistance (LTTR). You should be aware of polyisocyanurate insulation’s aging properties and the LTTR methodology, as well as NRCA’s opinion regarding whether LTTR accurately predicts polyisocyanurate insulation’s long-term R-value.

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