Roofing membranes are fabricated from strong, flexible, waterproof materials. They may be applied in multiple layers,as in the venerable Built-Up Roof (BUR), or they may consist of a single-ply membrane. Membranes usually contain a fabric made from felt, fiberglass, or polyester, for strength, which is laminated to or impregnated with a flexible polymeric material.The polymeric material may range from bituminous hydrocarbon materials such as asphalt, to synthetic rubber known as EPDM, to synthetic polymers such as polyvinyl chloride (PVC). The color of the polymer itself ranges from black to white, often depending on the amount of carbon black present. The upper surface of the membrane may be coated with a pigmented material which determines the color and solar reflectance, or it may simply be ballasted with roofing gravel. When a dark membrane is surfaced with roofing granules, the membrane has the appearance (and solar reflectance) of asphalt shingles.
For roofs ballasted with gravel, approximate values may be found at the end of this table, measured by Reagan and Acklam.
Table 3. General Solar Reflecting Characteristics of Roofing Membranes
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Product | Solar |Infrared |Temperature |Solar Reflectance| Reference
|Reflectance|Emittance | Rise | Index |
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Gray EPDM | 0.23 | 0.87 | 68 F | 21 | FSEC 1
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White EPDM | 0.69 | 0.87 | 25 F | 84 | FSEC 1
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Black EPDM | 0.06 | 0.86 | 83 F | -1 | FSEC 1
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Hypalon | 0.76 | 0.91 | 18 F | 95 | FSEC 1
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T-EPDM | 0.81 | 0.92 | 13 F | 102 | FSEC 1
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Firestone SBS | 0.26 | 0.92 | 63 F | 28 | FSEC 1
Bitumen on White| | | | |
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Smooth Bitumen | 0.06 | 0.86 | 83 F | -1 | FSEC 1
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White Granular | 0.26 | 0.92 | 63 F | 28 | FSEC 1
Surface Bitumen | | | | |
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Carlisle Syntec | 0.77 | 0.90 | 17 F | 96 | LBNL 1
System Brite-Ply| | | | |
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Ecology Roof | 0.80 | 0.90 | 14 F | 100 | LBNL 1
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Hypsam Roofing | 0.75 | 0.90 | 19 F | 93 | LBNL 1
Systems, Hyload | | | | |
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*Sarnafil Beige | 0.43 | 0.92 | 49 F | 49 | LBNL 4
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*Sarnafil Blue | 0.61 | 0.92 | 32 F | 73 | LBNL 4
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*Sarnafil White | 0.83 | 0.92 | 11 F | 104 | LBNL 4
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Stevens Hi-Tuff | 0.78 | 0.9 | 16 F | 97 | LBNL 1 EP white | | | | | ----------------------------------------------------------------------------------- Trocal Roofing | 0.77 | 0.9 | 17 F | 96 | LBNL 1 Systems,White | | | | | ----------------------------------------------------------------------------------- Trocal Roofing | 0.83 | 0.9 | 11 F | 104 | LBNL 1 Systems,White | | | | | ----------------------------------------------------------------------------------- Dark gravel on | 0.12 | 0.9 | 76 F | 9 | Reagan BUR roof | | | | | ----------------------------------------------------------------------------------- Light gravel on | 0.34 | 0.9 | 57 F | 37 | Reagan BUR roof | | | | | ----------------------------------------------------------------------------------- White-coated | 0.65 | 0.9 | 28 F | 79 | Reagan gravel on BUR | | | | | -----------------------------------------------------------------------------------
*represents new data