Standard: CAN/ULC-S770 – Standard Test Method for Determination of Long-Term Thermal Resistance of Closed-Cell Thermal Insulating Foams

Scope: This test is used on insulation materials which are subject to aging.

Applicable Products: Cellular plastic insulation materials, such as extruded polystyrene (XPS), spray polyurethane foam (PUR), and polyisocyanurate (PIR).

Test Procedure: The materials are tested for initial R-Value, then cut into thin slices to accelerate the aging (outgassing) process. The thin slices are then tested for initial R-value and at subsequent later times to determine the aging factors for different thicknesses of material.

End Result: The test determine a Long-Term Thermal Resistance (LTTR), which represents a five-year aged R-Value for the product.

Special Notes: This test is used by the Polyisocyanurate Manufacturers Association (PIMA) in their QualityMark program. An alternative method is ASTM C1303. CAN/ULC-S770 is a required test in CAN/ULC-S704 and ASTM C1289 for polyisocyanurate (PIR), CAN/ULC-S701 for extruded polystyrene (XPS) and CAN/ULC-S705.1 for spray polyurethane (PUR).


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