Long-Term Thermal Resistance (LTTR) is an advanced, scientifically supported method (based on ASTM C1303-95) used to predict the LTTR of polyisocyanurate insulation products. LTTR provides specifiers, design professionals and roofing contractors many advantages, including:
- Long-term thermal design value (15-year time-weighted average)
- Better understanding of thermal performance of foam insulation
- Advanced test method based on U.S. and Canadian consensus standards
- Technically supported, prescriptive method to measure the LTTR of polyisocyanurate insulation
- Meets requirements for LTTR values in the mandatory annex of ASTM C1289-02
With updated LTTR values that became available July 1, 2002, in Canada and Jan. 1, 2003, in the United States, the roofing industry gained a definitive standard for predicting LTTR values.
LTTR values of TERMICO™ polyisocyanurate insulation products from Dow Roofing Systems have been determined in accordance with CAN/ULC 5570. All test samples were third-party selected and tested by an accredited materials testing laboratory.
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