The document summarizes changes to test methods used by the Cool Roof Rating Council (CRRC) to rate solar reflectance and thermal emittance of roofing products. It describes two studies conducted to examine the impact of upgrading the Solar Spectrum Reflectometer device and adopting the Slide Method for thermal emittance testing. The studies found the test method changes resulted in small differences that did not warrant adoption of the new reflectometer version or extrapolation of slide test data, but some product types may be tested using the new methods going forward.

1. Jeffrey Steuben
Cool Roof Rating Council
Test Method Changes Impact
on Roofing Solar Reflectance
& Thermal Emittance

2. International Roof Coatings Conference – July 18, 2012Slide 2
CRRC Mission
• Ratings
• Research
• Education

3. International Roof Coatings Conference – July 18, 2012Slide 3
CRRC Resources
Directory Educational
Material

4. International Roof Coatings Conference – July 18, 2012Slide 4
The CRRC Process
Manufacturers send samples
to a test lab for initial testing
3-Year aging at three
test farm locations
Aged testing at a test lab

5. International Roof Coatings Conference – July 18, 2012Slide 5
Natural Aging
Ohio
cool/temperate
Arizona
hot/dry
Florida
hot/humid
Image credit: Atlas Weathering Services Group

6. International Roof Coatings Conference – July 18, 2012Slide 6
CRRC Label

7. International Roof Coatings Conference – July 18, 2012Slide 7
Why Cool Roofing?
Image credit: LBNL Heat Island Group

8. International Roof Coatings Conference – July 18, 2012Slide 8
Why Cool Roofing?
Image credit: LBNL Heat Island Group

9. International Roof Coatings Conference – July 18, 2012Slide 9
Surface Properties

10. International Roof Coatings Conference – July 18, 2012Slide 10
Solar Spectrum
Reflectometer (SSR)
Study
Image credit: Devices & Services Company

11. International Roof Coatings Conference – July 18, 2012Slide 11
How it works
Sensors:
Ultraviolet
Blue
Red
Infrared
Product sample
Tungsten
lamp
20° Angle
Image credit: Devices & Services Company

12. International Roof Coatings Conference – July 18, 2012Slide 12
SSR Spectrum Modeling
Image credit: Devices & Services Company

13. International Roof Coatings Conference – July 18, 2012Slide 13
Version 6 Changes
• Two additional virtual sensors
• Instrument calibrated against 155 tiles
• Ten irradiance options available
• Software update

14. International Roof Coatings Conference – July 18, 2012Slide 14
Objective
• Examine changes to C1549 resulting from
device hardware upgrade

15. International Roof Coatings Conference – July 18, 2012Slide 15
Round 1 Study
• 56 products tested
Version 5
Air mass 1.5
Version 6
1.5E output
Version 6
b891 output

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20. International Roof Coatings Conference – July 18, 2012Slide 20
Round 1 Conclusions
• v6 1.5E closely correlated with v5
– Mean difference .003
– Maximum difference .017
• v6 comparisons inconclusive
– Sample depreciation
– Product type variation
• Needs further study

21. International Roof Coatings Conference – July 18, 2012Slide 21
Round 2
• Confirm relationship between v5 and v6
Lab 6
Devices & Services
Lab 1 Lab 2 Lab 3 Lab 5Lab 4

22. International Roof Coatings Conference – July 18, 2012Slide 22
Sample Set

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27. International Roof Coatings Conference – July 18, 2012Slide 27
Round 2 Conclusions
• Eliminated sample depreciation problems
Average -.014 Average .015
v5
v6
v5v6

28. International Roof Coatings Conference – July 18, 2012Slide 28
Round 2 Conclusions
Average .004
v6
v5

29. International Roof Coatings Conference – July 18, 2012Slide 29
SSR Conclusions
• CRRC Technical Committee found
changes to be small
• Did not vote to adopt version 6 b891 mode
• Labs with v6 use v5 emulation mode to
maintain consistency

30. International Roof Coatings Conference – July 18, 2012Slide 30
Thermal Emittance
Slide Method
Study
Image credit: Devices & Services Company

31. International Roof Coatings Conference – July 18, 2012Slide 31
How it works
Image credit: Devices & Services Company

32. International Roof Coatings Conference – July 18, 2012Slide 32
Slide Method
Image credit: Devices & Services Company

33. International Roof Coatings Conference – July 18, 2012Slide 33
Objective
• Determine impact of Slide Method on
roofing products currently tested using
C1371
• Clarify role of sub-surface materials

34. International Roof Coatings Conference – July 18, 2012Slide 34
Sample Set
Sample # Description
1 Gray modified bitumen capsheet
2 Flat tile with white coating
3 Metal panel with blue coating
4 Curved tan tile
5 White PVC field-applied coating
6 Single Ply - 50 mil non-fleeceback
7 Single Ply - 50 mil fleeceback
8 Single Ply - 60 mil non-fleeceback
9 Single Ply - 60 mil fleeceback

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Trends – Higher Results

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Trends – Precision

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Conclusions
• CRRC voted to use Slide Method on all
products except coatings on uninsulated
metal panels
• Potentially will change to test field-applied
coatings using Slide Method

41. International Roof Coatings Conference – July 18, 2012Slide 41
Future Studies
ASTM E408
ASTM E1918 Precision & Bias
Directionally Reflective
Product Rating Method
Image credit: Kipp & Zonnen / Incognito Green Building

42. International Roof Coatings Conference – July 18, 2012Slide 42
Thank you
www.coolroofs.org
Jeffrey Steuben
Cool Roof Rating Council
jeff@coolroofs.org
(510) 482-4420 x288