Energy Code Terminology The new energy requirements and terms are being added to the energy codes. Solar Reflectance - the ability of the surface to reflect solar radiation away from that surface Infrared Emittance - the ability of a material to emit or radiate heat energy that builds up in the material. Cool Roof Color - A cool roof color is required for a conditioned building and it must meet the energy code Cool Roof finish values for Solar Reflectance and Infrared Emittance. These values will vary based upon the energy code requirements being met. Maximum Required U-Factor – The energy codes are lowing the established maximum required U-Factors for building construction. These new requirements will result in increased R-Values Conditioned Buildings - For a conditioned building, to get a building permit, a Building Envelope Energy Calculation will be required showing that the building is energy efficient. A building is conditioned if it has a system with heating capacity of more than 3.4 Btu/hr-ft2 or cooling capacity of more than 5 Btu/hr-ft2 .

Cool Roofing Terminology (cont’d) Solar Spectrum - radiation energy originating from the sun, including ultraviolet, visible and near infrared radiation. Conduction - the passing of heat through a roof material into the layer in contact directly beneath the surface Convection - the heating of the air that passes over a hot surface

Energy Balance on Roof Surface Total Solar Radiation Re-Emitted Energy Reflected Radiation Convection Roof Surface Layer Absorbed Energy Net Heat Flux Into Roof

Solar Energy Spectrum Ultraviolet (UV) Visible (VIS) Infrared (IR) 3% of total energy responsible for sunburn Visible (VIS) 40% of total energy visible light Infrared (IR) 57% of total energy felt as heat!

Cool Roofing Testing Methods ASTM E-903 - Reflectance (Laboratory) ASTM E-1918 - Reflectance (field test for variegated surfaces) ASTM C-1549 - Reflectance (portable device) ASTM E-408 - Emittance (Laboratory) ASTM C-1371 - Emittance (portable device)

Cool Roof Requirements High reflectivity Initial reading  65% ASTM E-903-96 or ASTM E-1918-97 OR Minimum Solar Reflectance Index (SRI) of 75% ASTM E-1980 for moderate wind conditions High emissivity 80% ATSM E 408-71 (1996) ASTM E-903-96 is a measurement of hemispherical reflectance over a range from 300 to 2500 nanometers, with a laboratory tabletop instrument. The total solar reflectance is calculated using a standard solar spectrum weighting method. ASTM E-1918-97 is a measurement of solar reflectance on horizontal and low-sloped surfaces with a pyranometer and natural sunlight. SRI is the reflective temperature of the surface with respect to a white and black standard surface. ASTM E –1980 is a method of calculating Solar Reflective Index using measured values of solar reflectance, emissivity, and a convective coefficient. D&S SSR is a measurement of solar reflectance using the portable Devices and Services Solar Spectrum Reflectometer. The test is suitable for lab or field use and the method is written by Oak Ridge National Laboratory, and published in the EPA Energy Star Memorandum of Understanding. This is the instrument we use in our lab. (It is not allowed by California criteria) They also have a emissivity requirement. (read requirement)

SOLAR ENERGY SPECTRUM

rsolar AND eIR ARE BOTH VERY IMPORTANT Total Solar Irradiation Convection Net Infrared Radiation hair(tair-ts) It rsolar It Reflected eIRDR with DR=s(Ts4-Tsky4 ) (asolarIt Absorbed) Net Heat Flux into Roof

Measuring Solar Reflectivity Solar Reflectivity describes an object’s ability to REFLECT solar radiation away from its surface. It is measured in the UV, IR and visible light wavelengths and therefore should not be confused with gloss/sheen which is based solely on visible light reflection Don’t confuse reflectivity with GLARE! 1.0 .75 .50 .25 Least Efficient Most Efficient Reflected Absorbed

Total Solar Reflectance A measure of reflectivity of an object over the entire spectrum of sunlight that hits the Earth’s surface, weighted by the intensity of sunlight at each wavelength.

Solar Reflectance Solar reflectance describes an objects ability to REFLECT solar radiation away from its surface It is measured in the UV, IR and visible light wavelengths and therefore should not be confused with gloss/sheen which is based solely on visible light reflection Don’t confuse reflectivity with GLARE!

Gloss/Sheen vs. Solar Reflectance GLARE is a CONCERN for commercial metal roofs Glare is the reflection of sunlight that can impair vision and create an ANNOYANCE This becomes CRITICAL around airports (impaired vision of pilots) and in tightly built residential neighborhoods The GLARE of a coated surface is controlled by the SHEEN Low Sheen = Low Glare Gloss/Sheen and Solar Reflectance are totally independent properties and do not have an affect on one another. A change in gloss and sheen does not change solar reflectance and vice versa.

Sunlight Sunlight Low IR Pigments High IR Pigments Suns Energy 6% Ultraviolet 52% Visible 42% Infrared 100% Sunlight Sunlight UV - Visible - Infrared UV - Visible - Infrared Low IR Reflectance High IR Reflectance Same Color Roof Low IR Pigments High IR Pigments Low IR Reflectance = Higher Temperature High IR Reflectance = Lower Temperature The same color roof can be cool or hot depending on the pigment in the roofing!!!

Sunlight Low IR Pigments High IR Pigments UV - Visible - Infrared Sunlight Low IR Reflectance Infrared Suns Energy 6% Ultraviolet 52% Visible 42% Infrared 100% Low IR Pigments High IR Reflectance Visible UV - Visible - Infrared UV Same Color Low IR Reflectance = Higher Temperature Careful selection of weatherable IR reflective pigments can produce dark, aesthetically pleasing colors that meet Energy Star roofing requirements. Infrared Visible UV High IR Pigments Energy Star (High Slope) (over 2:12 roof pitch) 25% Total Reflectance (Initial) 15% after 3 years Lower cooling costs Reduced Heat Island Effect Potential for for longer life cycle due to lower temperature High IR Reflectance = Lower Temperature The same color roof can be cool or hot depending on the pigment in the roofing!!!

Measuring Infrared Emissivity Efficiency of a surface ability to emit heat by radiation; the ratio of the radiant energy emitted by a surface to that emitted by a blackbody at the same temperature. Decreasing emittance may lead to increased energy use. Values are expressed from 0 to 1.0 Same type of values as solar reflectance 0 .25 .50 .75 1.0 Least Efficient Most Efficient  80% Cool Roof Requirement

Roof Surface Temperature Infrared Emittance Has a Lesser Impact Than Solar Reflectance (Example for Air Temperature of 98° F) Source: LBNL, ASTM D1980 solar reflectance emittance temperature (F) 0.70 0.75 124 0.70 0.90 122 0.55 0.75 139 0.70 0.75 125 0.80 0.75 115 T = 2° F As an example, reflectance may be much more important than emittance in some situations. Here, at 98 degrees Fahrenheit, we can see that if reflectance is held constant at 0.70, while the emittance is varied from 0.75 to 0.90 then the reduction in the roof surface temperature is only 2 degrees, which is insignificant. If the emittance is held constant at 0.85, while the reflectance is varied from 0.15 to 0.40, it can be seen that the difference in temperature can be 9 to 13 degrees hotter as the reflectivity goes down, thus showing the stronger effect of reflectance for this situation. This is recognized by the US Environmental Protection Agency Energy Star Roofs Program, which uses reflectance but not emittance for their roofing material ratings. T = 10 - 14° F

Color Selection Light and medium shades usually meet the 0.25 requirement Dark colors can usually be reformulated to meet the 0.25 requirement Dark colors absorb nearly all the visible light spectrum and retains the most energy. This is why dark clothes are hotter and it is better to wear light colors in the summer to keep cool. So do you have to limit your paint choices to light colors? No. Valspar has already reformulated our most popular coil coatings to have higher reflectivity rates. A full range of colors is now available.

The Primary Energy Concern is the Heat in the Building Dark materials ABSORB MORE HEAT from the sun. When those dark surfaces are roofs, some of the heat is TRANSFERRED INSIDE When that happens, the Urban Heat Island Effect becomes a factor.

The Problem – Metal Stability Metal Expansion and Contraction: Standing seam applications are subject to DISTORTION by heat The temperature variations create MOVEMENT within the standing seam leg, WEAR, and OIL CANNING Oil Canning: The STRESS in the platform angles of the LEG causes distortion, exasperated by heat absorption

Cool Coating Benefits Heat is REFLECTED away from buildings All the advantages of greater reflectivity can be had WITHOUT SACRIFICING COLOR CHOICE Dramatically increases the reflectivity of medium to dark colors to such a degree that the product will meet the ENERGY STAR specifications for STEEP SLOPE Cool Roofs Smog is REDUCED when environmental temperatures are reduced

Impact on Temperature and Energy Consumption Rule of Thumb: FOR EVERY 1% INCREASE IN ROOF REFLECTANCE, TEMPERATURE DECREASES 1°F example: Improving reflectance from 10% to 50% lowers surface temperature 40°F FOR EVERY 10% INCREASE IN ROOF REFLECTANCE, COOLING/HEATING ENERGY COSTS DROP 2¢/ft2 (warm climates) Per LBNL: based on DOE 2 model, LBNL models, ORNL calculator, EnergyPlus model

Roofing Material Thermal Properties Initial Solar Reflectance Infrared Emittance Metal (unpainted) 0.60-0.80 0.04-0.10 Metal (painted and granular coated) 0.10-0.75 * 0.75 + Comp Asphalt Shingles 0.05-0.25 0.90 Modified Bitumen 0.05-0.25 0.90 Built Up Roofing 0.05-0.80 0.90 Concrete/Clay Tile 0.20-0.70 0.90 White Single Ply Membrane 0.70-0.80 0.85 + Source: ORNL and LBNL Taking a look at the Thermal Properties of various roofing materials, we can see how they perform with initial Solar Reflectance and Infrared Emittance. Unpainted metal can have very high reflectance but very low emittance. On the other hand, painted and granular coated metal can have quite a range of initial reflectance values, and emittance as high as 0.75. Many competing roofing materials can have very high emittance but very low or up to very high reflectance, depending upon many specific properties afforded by color, texture, and other factors. Either high reflectance or high emittance or both of these properties may be needed for a given application. It is important for architects, building owners, specifiers, codes & standards officials and other stakeholders to have the facts on Cool Metal Roofing so that knowledgeable selections can be made. Metal roofing should not be rejected out of hand due to a misunderstanding about a particular property or its significance in a given instance. * depending on color Emissivity is generally high in coatings and paint films, but very low in unpainted metallic surfaces

Roof Surface Temperature Infrared Emittance Has Less Impact Than Solar Reflectance (Example for Air Temperature of 98° F) Source: LBNL, ASTM D1980 solar reflectance emittance temperature (F) 0.70 0.75 124 0.70 0.90 122 0.55 0.75 139 0.70 0.75 125 0.80 0.75 115 T = 2° F As an example, reflectance may be much more important than emittance in some situations. Here, at 98 degrees Fahrenheit, we can see that if reflectance is held constant at 0.70, while the emittance is varied from 0.75 to 0.90 then the reduction in the roof surface temperature is only 2 degrees, which is insignificant. If the emittance is held constant at 0.85, while the reflectance is varied from 0.15 to 0.40, it can be seen that the difference in temperature can be 9 to 13 degrees hotter as the reflectivity goes down, thus showing the stronger effect of reflectance for this situation. This is recognized by the US Environmental Protection Agency Energy Star Roofs Program, which uses reflectance but not emittance for their roofing material ratings. T = 10 - 14° F

Urban Heat Island Effect Urban Heat Island - a built environment wherein the large proportion of dark surfaces such as asphalt paving and dark roofs absorb solar radiation and radiate the heat back into the atmosphere causing higher ambient temperatures and higher pollution levels Urban areas are 6-8 °F warmer than suburbs (Dark pavements, dark roofing and less vegetation) Roof surface temperature has an effect on the following items: (lower temperature = less smog, less pollution, lower peak energy demand) High reflectance/emittance = low surface temperatures Emittance is recognized, however, in helping to mitigate the Urban Heat Island effect. As we have experienced ourselves, dark pavements, dark roofing, and less vegetation can make it seem hotter. In built-up urban areas, it is hotter, as much as 6 to 8 degrees hotter. For this reason, the roof surface temperatures become important and thus, both reflectance and emittance can help create lower temperatures. Let’s see what this looks like from a satellite.

Thermal Image of Washington, DC This image shows, in red, the higher temperatures in Washington, D.C., during the summer period. The build-up areas in red are literally hotter than the adjacent areas, thus creating more of a cooling load and more peak demand for energy use. That’s not the only problem caused by urban heat islands, as we can see in the next slide. Hottest Surface Colored in Red

Heat is a catalyst for smog Smog Formation Los Angeles, California, is infamous for its smog. Part of the reason for smog is the urban heat island, since heat serves as a catalyst for its formation. The number of cars on the road is about the same between summer and winter yet it’s the summer that suffers the most from smog. Thus, metropolitan areas have several reasons to consider the urban heat island in their planning. The more we know about the various phenomenon, the better we can inform others. Let’s look at some of the independent laboratories that have the expertise and testing supporting Cool Metal Roofing’s initiatives. Heat is a catalyst for smog The air in Los Angeles is noticeably cleaner during winter, yet the number of cars on the road is approximately the same as in summer.

Roof Energy Savings R-5 R-15 Savings, $/ft² per year City White Membrane Unpainted Galvalume Aluminum Coating $0.25 R-5 R-15 $0.20 White Membrane or White Painted Metal $0.15 Unpainted Galvalume Savings, $/ft² per year $0.10 Aluminum Coating By using the U.S. Department of Energy/ORNL Cool Roof Calculator, it can be seen how different types of roofing compare in various cities with R-5 and R-15 insulation. The “red bar” shows how the savings per year are dramatically greater for white membrane or painted metal in Phoenix, while the savings are somewhat lower in Knoxville. The “green bar” shows, however, how greater energy savings in Chicago come from an unpainted metal roof. The “yellow bar” shows the performance of aluminum coating. However, dark colors can sometimes perform well, as shown in the next few slides. $0.05 $0.00 Knoxville Phoenix Chicago Knoxville Phoenix Chicago City

Heating Degree Day The sum of the degree days for heating, using a common base of 65°F, used with other factors to evaluate the energy requirements of a heating season. Example for HDD Base 65º F For any one day, when the mean temperature is less than 65 °F, there are as many degree- days as degrees F temperature difference between the mean temperature for the day and 65°F. Annual heating degree-days are the sum of the degree-days over a calendar year.

3600 HDD Isothermal Line

Building Envelope One of most important factors in designing energy-efficient buildings Strongly affects heating and cooling loads (HVAC Energy) Investment in insulation or energy-efficient windows can result in smaller HVAC systems to help pay for the better envelope

Envelope Compliance Methods Prescriptive Trade-off Energy Cost Budget (Whole Building)

Prescriptive Method Specified for Location Roof Umax 0.065 Specified for Location ASHRAE 90.1 – 16 Climate Zones Insulation for Opaque Components Maximum U-Factor or Minimum R Roofs, Walls, Floors Fenestration Maximum SHGC and U-Factor Windows, Skylights

Trade-Off Offers flexibility Thermal performance of one envelope component can fail to meet prescriptive requirement as long as other components perform better than what is required Proof of compliance is more involved Overall Heat Loss Overall Heat Gain

NAIMA Prescriptive Solutions Screw Down w/R-19 U=0.098 SSR w/R-19 U=0.065 ASHRAE = 0.065 SSR 2 Layers R-19 U=0.046