1.0   Scope

This appendix covers the test requirements used to measure the R-value of non-display panels and non-display doors of a walk-in cooler or walk-in freezer.

2.0   Definitions

The definitions contained in §431.302 apply to this appendix.

3.0   Additional Definitions

3.1   Edge region means a region of the panel that is wide enough to encompass any framing members. If the panel contains framing members (e.g., a wood frame) then the width of the edge region must be as wide as any framing member plus an additional 2 in. ± 0.25 in.

4.0   Test Methods, Measurements, and Calculations

4.1   The R value shall be the 1/K factor multiplied by the thickness of the panel.

4.2   The K factor shall be based on ASTM C518 (incorporated by reference; see §431.303).

4.3   For calculating the R value for freezers, the K factor of the foam at 20 ± 1 degrees Fahrenheit (average foam temperature) shall be used. Test results from a test sample 1 ±0.1-inches in thickness may be used to determine the R value of panels with various foam thickness as long as the foam is of the same final chemical form.

4.4   For calculating the R value for coolers, the K factor of the foam at 55 ± 1 degrees Fahrenheit (average foam temperature) shall be used. Test results from a test sample 1 ± 0.1-inches in thickness may be used to determine the R value of panels with various foam thickness as long as the foam is of the same final chemical form.

4.5   Foam shall be tested after it is produced in its final chemical form. For foam produced inside of a panel (“foam-in-place”), “final chemical form” means the foam is cured as intended and ready for use as a finished panel. For foam produced as board stock (typically polystyrene), “final chemical form” means after extrusion and ready for assembly into a panel or after assembly into a panel. Foam from foam-in-place panels must not include any structural members or non-foam materials. Foam produced as board stock may be tested prior to its incorporation into a final panel. A test sample 1 ± 0.1-inches in thickness must be taken from the center of a panel and any protective skins or facers must be removed. A high-speed band-saw and a meat slicer are two types of recommended cutting tools. Hot wire cutters or other heated tools must not be used for cutting foam test samples. The two surfaces of the test sample that will contact the hot plate assemblies (as defined in ASTM C518 (incorporated by reference, see §431.303)) must both maintain ±0.03 inches flatness tolerance and also maintain parallelism with respect to one another within ±0.03 inches. Testing must be completed within 24 hours of samples being cut for testing.

4.6   Internal non-foam member and/or edge regions shall not be considered when testing in accordance with ASTM C518 (incorporated by reference, see §431.303).

4.7   For panels consisting of two or more layers of dissimilar insulating materials (excluding facers or protective skins), test each material as described in sections 4.1 through 4.6 of this appendix. For a panel with N layers of insulating material, the overall R-Value shall be calculated as follows:

Where:

ki is the k factor of the ith material as measured by ASTM C518, (incorporated by reference, see §431.303);

ti is the thickness of the ith material that appears in the panel; and

N is the total number of material layers that appears in the panel.

[81 FR 95803, Dec. 28, 2016]