Cool Roofing and Codes

When cool roofing first came on the scene several years ago, a lot happened in a short amount of time. Since then, things have calmed down a bit in terms of new products and developments, but what has changed is the way in which building codes and green building programs are addressing the topic of cool roofs.

As Rodger Russ, North American sales manager of roofing for Butler Manufacturing, Kansas City, Mo., notes cool metal roofing has become the industry standard. “At one time, several years back, not every major paint supplier or every metal manufacturer used cool roofing-type paint, and now, all the major manufacturers and their paint suppliers provide all their standard colors in cool roofing,” he says. “It’s not as trendy as it used to be because it’s become more of the norm in the industry.”

Robert A. Zabcik, PE, LEED AP BD+C, director, research and development at Houston-based NCI Group Inc., agrees, saying, that cool roofing hasn’t changed much in terms of how things are quantified on a given project, but what has changed is the different energy code adoptions. “The subject of cool roofing in general has actually changed quite a bit in terms of the amount of importance it seems to be carrying, and where geographically, and to a large extent, politically, those things matter,” he says.

Energy Codes

Changes within recent energy codes are where most of the current changes in the cool roofing industry have occurred. “Nowadays, the energy code is changing our business,” Russ explains. “As more and more states and local municipalities adopt energy codes, the need for more insulation and things of that nature are driving projects more so now than cool roofing.”

In recent years, Brian Partyka, executive vice president of business development at Drexel Metals Inc., Louisville, Ky., notes, “There’s been a move away from solar reflectance and toward the performance of the assembly and the system along with product declarations and life cycle costing.”

“The energy code is driving the metal roofing industry a little bit more, as adoptions in the energy code change from 2012 to 2014,” adds Russ. “Metal roofing and the insulation requirements, not only for new construction, but also for re-roofs and retrofits are being more scrutinized, and thus, the requirements for more insulation are increasing.”

Contractors need to be aware of the changes in the energy codes. “If they don’t educate themselves about the energy code requirements and their local municipality has adopted an energy code, they could find themselves with a non-code-compliant roof, which could be very costly in the end for them,” Russ explains.

California’s Title 24

California’s Building Energy Efficiency Standards, Title 24, which defines minimum prescriptive values for thermal emittance, three-year aged reflectance and solar reflective index
(SRI), are updated approximately every three years. The 2013 standards went into effect July 1, 2014. According to the CRRC, the major changes to California’s cool roof requirements include increases in minimum aged solar reflectance for nonresidential and residential low-slope (from 0.55 to 0.63) and steep-slope roofs across California’s 16 climate zones; removal of roof weight designations; updated equation to calculate the aged solar reflectance for field-applied coatings; roof/ceiling insulation tradeoff for aged solar reflectance; and requirements for additions, alterations and repairs that apply to the roof/ceiling insulation tradeoff for aged solar reflectance of roofing being replaced, recovered or recoated. Additionally, the updated standards retained an allowance for using the SRI as an alternative to thermal emittance and aged solar reflectance when complying with the cool roofing requirements.

Mike Petersen, president of Elk Grove Village, Ill.-based Petesen Aluminum Corp., explains that the three-year aging requirement for solar reflectivity for a low-slope roof starts at 0.65 reflectivity or above and is allowed to deteriorate down to a 0.50 reflectivity over three years. For steep-slope roofs, the starting reflectivity needs to be 0.25 or better, and is allowed to go down to 0.15 after three years.

“Almost every color we’ve tested, after three years, is at the same level or within 1 percent of its initial reflectivity,” he says. “Basically Kynar and Hylar do not lose its reflectivity over time, and if you want long-term performance on a building, that’s the way to go.”

LEED v4

As the U.S. Green Building Council moved toward LEED v4, there have been some changes in how projects receive credits. As Partyka explains, LEED is focusing on more Materials and Resources credits for solar reflectance, which was always a big component of getting the solar reflectance index up to 29 percent or greater. “What’s changed with LEED is that there’s much more transparency on performance,” he says. “They re-wrote the Materials and Resources section to focus more on life cycle and product declaration, mechanicals, extraction of all materials, and then there is a new credit category that addresses the project location and transportation of materials.”

Thomas Taylor, general manager of St. Louis-based Vertegy LLC, notes that the places in LEED v4 where roofing contributes is the heat island effect, energy to a certain extent, the way that it models and affects the building, and in the materials choice. “Cool roof products, along as they abide by the SRI calculations, and the SRI calculations are available to the project team through the manufacturers, [the points] are pretty easily solved,” he says.

Previously in the Material and Resources section, Taylor explains that cool roof products easily received points for having a high amount of recycled content, and in a lot of cases were being manufactured locally. “In the new LEED system, the way the materials are now scored or weighed has changed, so now instead of just recycled content, they’re looking for products that manufacturers have gone one step further in the ISO process and have done Environmental Product Declarations,” Taylor says. “While a product’s recycled amount and the region of where it’s made is still important, it’s taken somewhat of a backseat to try and spur market transformation in becoming more transparent by having manufacturers openly, and in some cases for extra credit, have products third-party verified, which shows how they make their products, who they source their products from, how the materials get to the manufacturers, while tracking all the environmental impacts.”

Jacob Kriss, media specialist for the U.S. Green Building Council, describes how cool metal roofing systems specifically fit into LEED v4. From a Materials and Resources perspective, Kriss explains that roofing assemblies are a major system for a building project, and are therefore included in the Whole Building Life Cycle Assessment option (option 4) within the LEED v4 MR credit Building Life Cycle Impact Reduction. “In the credit, the beneficial attributes of metal roofing as a material can contribute toward credit achievement,” he says.

Kriss adds that all materials used in a building project are eligible to contribute toward the three Building Product Disclosure and Optimization credits in LEED v4: Environmental Product Declarations, Sourcing of Raw Materials and Material Ingredients.

From a Sustainable Sites perspective, cool metal roofing can contribute toward the Heat Island Reduction credit, which updated the roof SRI requirements, included three-year aged SRI and SR values and increased weighted SRI average calculation methodology.

Energy Star

While the U.S. Environmental Protection Agency‘s (EPA) Energy Star program is a performance-based program that doesn’t look at specific technologies building use to achieve energy savings, Lauren Hodges, director of communications for Energy Star for commercial buildings and industrial plants, notes that cool roofs are a proper strategy for many of its partners. “We provide tools and resources to our partners who want to strategically manage energy use across their organization, and then we help them measure and assess their performance,” she says. “If their buildings are performing at the top of the market, they can earn EPA’s Energy Star certification.”

However, there have been recent changes to Energy Star Version 3.0 Roof Products Specification and Test Methods, which will take effect on July 1, 2017. These changes require all products to use weathered ratings from three different climate zones, or aged testing. Values from all three zones will represent the averaged values within each individual climate zone, consistent with the CRRC Product Rating Program procedures.

Petersen notes that Energy Star 3.0 requires manufacturers to have a third test fence farm in urban areas for a color to be qualified. “What that effectively means, in our case, for some of our colors, we have to back off to whatever the color family number is instead of using the specific reflectance number that we have for each color that we’ve tested,” he explains.