Jeffrey SteubenCool Roof Rating Council

Test Method Changes Impact on Roofing Solar Reflectance & Thermal Emittance

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CRRC Mission

• Ratings • Research• Education

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CRRC ResourcesDirectory Educational

Material

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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

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Natural AgingOhiocool/temperate

Arizonahot/dry

Floridahot/humid

Image credit: Atlas Weathering Services Group

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CRRC Label

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Why Cool Roofing?

Image credit: LBNL Heat Island Group

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Why Cool Roofing?

Image credit: LBNL Heat Island Group

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Surface Properties

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Solar Spectrum Reflectometer (SSR) Study

Image credit: Devices & Services Company

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How it works

Sensors:

UltravioletBlueRedInfrared

Product sample

Tungsten

lamp

20° Angle

Image credit: Devices & Services Company

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SSR Spectrum Modeling

Image credit: Devices & Services Company

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Version 6 Changes • Two additional virtual sensors• Instrument calibrated against 155 tiles• Ten irradiance options available• Software update

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Objective• Examine changes to C1549 resulting from

device hardware upgrade

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Round 1 Study• 56 products tested

Version 5Air mass 1.5

Version 6 1.5E output

Version 6b891 output

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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

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Round 2• Confirm relationship between v5 and v6

Lab 6

Devices & Services

Lab 1 Lab 2 Lab 3 Lab 5Lab 4

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Sample Set

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Round 2 Conclusions• Eliminated sample depreciation problems

Average -.014 Average .015

v5v6

v5v6

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Round 2 Conclusions

Average .004

v6

v5

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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

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Thermal Emittance Slide Method Study

Image credit: Devices & Services Company

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How it works

Image credit: Devices & Services Company

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Slide Method

Image credit: Devices & Services Company

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Objective• Determine impact of Slide Method on

roofing products currently tested using C1371

• Clarify role of sub-surface materials

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Sample SetSample # Description

1 Gray modified bitumen capsheet2 Flat tile with white coating3 Metal panel with blue coating4 Curved tan tile5 White PVC field-applied coating6 Single Ply - 50 mil non-fleeceback7 Single Ply - 50 mil fleeceback8 Single Ply - 60 mil non-fleeceback9 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

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Future StudiesASTM E408

ASTM E1918 Precision & Bias

Directionally Reflective Product Rating Method

Image credit: Kipp & Zonnen / Incognito Green Building

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Thank you

www.coolroofs.orgJeffrey Steuben

Cool Roof Rating Counciljeff@coolroofs.org

(510) 482-4420 x288