Note:

Prior to October 31, 2023, representations with respect to the R-value for insulation of envelope components of walk-in coolers and walk-in freezers, including compliance certifications, must be based on testing conducted in accordance with the applicable provisions of 10 CFR part 431, subpart R, appendix B, revised as of January 1, 2022. Beginning October 31, 2023, representations with respect to R-value for insulation of envelope components of walk-in coolers and walk-in freezers, including compliance certifications, must be based on testing conducted in accordance with this appendix.

0. Incorporation by Reference

DOE incorporated by reference in § 431.303 the entire standard for ASTM C518-17. However, certain enumerated provisions of ASTM C518-17, as set forth in paragraph 0.1 of this appendix, are inapplicable. To the extent there is a conflict between the terms or provisions of a referenced industry standard and the CFR, the CFR provisions control.

0.1 ASTM C518-17

(a) Section 1 Scope, is inapplicable,

(b) Section 4 Significance and Use, is inapplicable,

(c) Section 7.3 Specimen Conditioning, is inapplicable,

(d) Section 9 Report, is inapplicable,

(e) Section 10 Precision and Bias, is inapplicable,

(f) Section 11 Keywords, is inapplicable,

(g) Annex A2 Equipment Error Analysis, is inapplicable,

(h) Appendix X1 is inapplicable,

(i) Appendix X2 Response of Heat Flux Transducers, is inapplicable, and

(j) Appendix X3 Proven Performance of a Heat Flow Apparatus, is inapplicable.

0.2 [Reserved] 1. General

The following sections of this appendix provide additional instructions for testing. In cases where there is a conflict, the language of this appendix takes highest precedence, followed by ASTM C518-17. Any subsequent amendment to a referenced document by the standard-setting organization will not affect the test procedure in this appendix, unless and until the test procedure is amended by DOE. Material is incorporated as it exists on the date of the approval, and a notification of any change in the incorporation will be published in the Federal Register.

2. 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.

3. Definitions

The definitions contained in § 431.302 apply to this appendix.

4. Additional Definitions

4.1 Edge region means a region of the envelope component that is wide enough to encompass any framing members. If the envelope component 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.

5. Test Methods, Measurements, and Calculations

5.1 General. Foam shall be tested after it is produced in its final chemical form. For foam produced inside of an envelope component (“foam-in-place”), “final chemical form” means the foam is cured as intended and ready for use as a finished envelope component. For foam produced as board stock (e.g., polystyrene), “final chemical form” means after extrusion and ready for assembly into an envelope component or after assembly into an envelope component. Foam must not include any structural members or non-foam materials during testing in accordance with ASTM C518-17. When preparing the specimen for test, a high-speed bandsaw or a meat slicer are two types of recommended cutting tools. Hot wire cutters or other heated tools shall not be used for cutting foam test specimens.

5.2 Specimen Preparation

5.2.1 Determining the thickness around the perimeter of the envelope component, tp. The full thickness of an envelope component around the perimeter, which may include facers on one or both sides, shall be determined as follows:

5.2.1.1 At least 8 thickness measurements shall be taken around the perimeter of the envelope component, at least 2 inches from the edge region, and avoiding any regions with hardware or fixtures.

5.2.1.2 The average of the thickness measurements taken around the perimeter of the envelope component shall be the thickness around the perimeter of the envelope component, tp.

5.2.1.3 Measure and record the width, wp, and height, hp, of the envelope component. The surface area of the envelope component, Ap, shall be determined as follows:

Where: wp = width of the envelope component, in.; and hp = height of the envelope component, in.

5.2.2. Removing the sample from the envelope component.

5.2.2.1. Determine the center of the envelope component relative to its height and its width.

5.2.2.2. Cut a sample from the envelope component that is at least the length and width dimensions of the heat flow meter, and where the marked center of the sample is at least 3 inches from any cut edge.

5.2.2.3. If the center of the envelope component contains any non-foam components (excluding facers), additional samples may be cut adjacent to the previous cut that is at least the length and width dimensions of the heat flow meter and is greater than 12 inches from the edge region.

5.2.3. Determining the thickness at the center of the envelope component, tc. The full thickness of an envelope component at the center, which may include facers on one or both sides, shall be determined as follows:

5.2.3.1. At least 2 thickness measurements shall be taken in each quadrant of the cut sample removed from the envelope component per section 5.2.2 of this appendix, for a total of at least 8 measurements.

5.2.3.2. The average of the thickness measurements of the cut sample removed from the envelope component shall be the overall thickness of the cut sample, tc.

5.2.3.3. Measure and record the width and height of the cut sample removed from the envelope component. The surface area of the cut sample removed from the envelope component, Ac., shall be determined as follows:

Where: wc = width of the cut sample removed from the envelope component, in.; and hc = height of the cut sample removed from the envelope component, in.

5.2.4. Determining the total thickness of the foam within the envelope component, tfoam. The average total thickness of the foam sample, without facers, shall be determined as follows:

5.2.4.1. Remove the facers on the envelope component sample, while minimally disturbing the foam.

5.2.4.2. Measure the thickness of each facer in 4 locations for a total of 4 measurements if 1 facer is removed, and a total of 8 measurements if 2 facers are removed. The average of all facer measurements shall be the thickness of the facers, tfacers, in.

5.2.4.3. The average total thickness of the foam, tfoam, in., shall be determined as follows:

Where: tc = the average thickness of the center of the envelope component, in., as determined per sections 5.2.3.1 and 5.2.3.2 of this appendix; Ac = the surface area of the center of the envelope component, in 2., as determined per section 5.2.3.3 of this appendix; tp = the average thickness of the perimeter of the envelope component, in., as determined per sections 5.2.1.1 and 5.2.1.2 of this appendix; Ap = the average thickness of the center of the envelope component, in 2, as determined per section 5.2.1.3 of this appendix; tfacers = the average thickness of the facers of the envelope component, in., as determined per section 5.2.4.2 of this appendix.

5.2.5. Cutting, measuring, and determining parallelism and flatness of a 1-inch-thick specimen for test from the center of the cut envelope component sample.

5.2.5.1. Cut a 1 ± 0.1-inch-thick specimen from the center of the cut envelope sample. The 1-inch-thick test specimen shall be cut from the point that is equidistant from both edges of the sample (i.e., shall be cut from the center point that would be directly between the interior and exterior space of the walk-in).

5.2.5.2. Document through measurement or photographs with measurement indicators that the specimen was taken from the center of the sample.

5.2.5.3 After the 1-inch specimen has been cut, and prior to testing, place the specimen on a flat surface and allow gravity to determine the specimen's position on the surface. This will be side 1.

5.2.5.4 To determine the flatness of side 1, take at least nine height measurements at equidistant positions on the specimen (i.e., the specimen would be divided into 9 regions and height measurements taken at the center of each of these nine regions). Contact with the measurement indicator shall not indent the foam surface. From the height measurements taken, determine the least squares plane for side 1. For each measurement location, calculate the theoretical height from the least squares plane for side 1. Then, calculate the difference between the measured height and the theoretical least squares plane height at each location. The maximum difference minus the minimum difference out of the nine measurement locations is the flatness of side 1. For side 1 of the specimen to be considered flat, this shall be less than or equal to 0.03 inches.

5.2.5.5 To determine the flatness of side 2, turn the specimen over and allow gravity to determine the specimen's position on the surface. Repeat section 5.2.5.4 to determine the flatness of side 2.

5.2.5.6 To determine the parallelism of the specimen for side 1, calculate the theoretical height of the least squares plane at the furthest corners (i.e., at points (0,0), (0,12), (12,0), and (12,12)) of the 12-inch by 12-inch test specimen. The difference between the maximum theoretical height and the minimum theoretical height shall be less than or equal to 0.03 inches for each side in order for side 1 to be considered parallel.

5.2.5.7 To determine the parallelism of the specimen for side 2, repeat section 5.2.5.6 of this appendix.

5.2.5.8 The average thickness of the test specimen, L, shall be 1 ± 0.1-inches determined using a minimum of 18 thickness measurements (i.e., a minimum of 9 measurements on side 1 of the specimen and a minimum of 9 on side 2 of the specimen). This average thickness shall be used to determine the thermal conductivity, or K-factor.

5.3 K-factor Test. Determine the thermal conductivity, or K-factor, of the 1-inch-thick specimen in accordance with the specified sections of ASTM C518-17. Testing must be completed within 24 hours of the specimen being cut for testing per section 5.2.5 of this appendix.

5.3.1 Test Conditions.

5.3.1.1 For freezer envelope components, the K-factor of the specimen shall be determined at an average specimen temperature of 20 ± 1 degrees Fahrenheit.

5.3.1.2 For cooler envelope components, the K-factor of the specimen shall be determined at an average specimen temperature of 55 ± 1 degrees Fahrenheit.

5.4 R-value Calculation.

5.4.1 For envelope components consisting of one homogeneous layer of insulation, calculate the R-value, h-ft 2- °F/Btu, as follows:

Where: tfoam = the total thickness of the foam, in., as determined in section 5.2.4 of this appendix; and λ = K-factor, Btu-in/(h-ft 2- °F), as determined in section 5.3 of this appendix.

5.4.2 For envelope components consisting of two or more layers of dissimilar insulating materials (excluding facers or protective skins), determine the K-factor of each material as described in sections 5.1 through 5.3 of this appendix. For an envelope component with N layers of insulating material, the overall R-value shall be calculated as follows:

Where: ti is the thickness of the ith material that appears in the envelope component, inches, as determined in section 5.2.4 of this appendix; λi is the k-factor of the ith material, Btu-in/(h-ft 2- °F), as determined in section 5.3 of this appendix; and N is the total number of material layers that appears in the envelope component.

5.4.3 K-factor test results from a test sample 1 ± 0.1-inches in thickness may be used to determine the R-value of envelope components with various foam thicknesses as long as the foam throughout the panel depth is of the same final chemical form and the test was completed at the same test conditions that the other envelope components would be used at. For example, a K-factor test result conducted at cooler conditions cannot be used to determine R-value of a freezer envelope component.

[88 FR 28843, May 4, 2023, as amended at 88 FR 73217, Oct. 25, 2023]