CAN ULC-S770-15-REV1 2018 PDF Download

The CAN ULC-S770-15-REV1 2018 standard outlines a procedure for determining the long-term thermal resistance (LTTR) of closed-cell foam products. The LTTR is measured after 5 years of storage in a laboratory environment, and the standard also provides a method for predicting the LTTR based on an accelerated laboratory test.

The procedure is based on two ASTM test methods, ASTM C1303 and ASTM C518, and involves slicing and scaling the foam products to estimate the change in thermal resistivity. The standard applies to both faced and unfaced foam products and does not consider the effect of facers on the LTTR.

This test procedure is applicable to cellular plastic insulation that retains a gas or mixture of gases (other than air) for more than 180 days. If the thermal resistivity of a product changes by more than 3% over this 180-day period, this test procedure must be used. The standard specifies the reference time, sampling requirements, and testing requirements for determining the LTTR of closed-cell foams such as extruded polystyrene, sprayed polyurethane, and polyisocyanurate.

The revisions made in this edition of the standard include clarifications of terms such as "base formulation" and "mean temperature." There are also new clauses that address the testing of materials thicker than 75 mm, as well as a new section on testing actual 5-year samples.