Cool Roofs in Northern Climates Provide More Bang for the Buck Than We Thought

Electricity demand in Washington, D.C., plotted against daily high temperature. Source: Weather Underground, PJM Interconnection (PJME).

(Figure 1) Electricity demand in Washington, D.C., plotted against daily high temperature. Source: Weather Underground, PJM Interconnection (PJME).

The energy savings from cool, reflective, roofs have long made them the go-to roof choice in warmer and temperate climates here in the United States. Both ASHRAE and the International Energy Conservation Code have included roof surface reflectivity requirements for a number of years. About half of all new flat roofs installed in the country are highly reflective and in some product categories white options outsell dark ones by a substantial margin. It is hard to argue with the notion that, where it is warm, the roofs should be white. While the building-level impacts of cool roofs in cool climates has been covered in the past, very little has been written about the broader economic benefits of cooler buildings and cities. When we include the economic impacts of factors like improved health, air quality, and energy savings, the case for cool roofs in cool climates looks even better.

The Benefits of Cool Roofs Go Way Beyond the Building

The building-level impacts of cool roofs are a central part of the discussion about whether they should be used in cold climates. However, it is also important to recognize the substantial co-benefits that come from installing cool roofs in terms of healthier and more comfortable people, improved productivity, better air quality, and increased economic prosperity. While the economic benefits of cool roofs are substantial, they may not always be fully included in a building owner’s roof buying decision.

How much cooler could our cities become if we added more reflective roofs? In a comprehensive review on this topic, Santamouris 2012 found that when a global increase of the city’s albedo is considered, the expected mean decrease of the average ambient temperature is close to 0.5°F (0.3°C) per 0.1 increase in reflectivity, while the corresponding average decrease of the peak ambient temperature is close to 1.6°F (0.9°C). The cooling impact of reflective roofs in certain neighborhoods could be significantly better, though. A study of Chicago by Notre Dame University found that installing reflective roofs cooled city surfaces by around 3.5 to 5.5°F (2-3°C), but surfaces in the downtown core cooled by 12.5 to 14.5°F (7-8°C).

Cool Cities Are Energy Savers

We have started to better understand and quantify the impact in cities that are able to get a degree or two of cooling. The most obvious benefit is that cooler cities demand less energy on hot days. The graph in Figure 1 plots electricity demand in

Lowering the temperature of cities can bring a multitude of benefits. Source: Global Cool Cities Alliance.

(Figure 2) Lowering the temperature of cities can bring a multitude of benefits. Source: Global Cool Cities Alliance.

Washington, D.C., against the maximum temperature every day for 5 years (2010–2015). The graph’s shape looks very similar to plots from other cities with high penetrations of air conditioning units. Demand for electricity climbs rapidly above about 80°F. When the maximum temperature is 90°F, the city requires 21 percent more electricity, on average, than on 80°F days. At 95°F, demand has spiked by nearly 40 percent over the 80°F baseline. Charges for peak electricity demand are a major expense for commercial and industrial building operators and, in seventeen states, for homeowners as well. Further, peaking demand is often met by less efficient, more expensive, and dirtier power plants that worsen air quality. At worst, peak demand can cause productivity-killing service interruptions or brownouts.

Cooler Cities Are Healthier Places

Heat is a potent but silent killer. On average, heat kills more people than any other natural disaster, and heat-related deaths tend to be underreported. In 2015, Scientific American reported that 9 out of the 10 deadliest heat events in history have occurred since 2000 and have led to nearly 130,000 deaths. Cities on dangerously hot days experience 7 percent to 14 percent spikes in mortality from all causes.

Heat stress and stroke are only the tip of the pyramid of heat health impacts. Heat puts significant additional stress on people already suffering from diseases of the heart, lungs, kidneys, and/or diabetes. A recent study finds that every 1.5°F increase in temperatures will kill 5.4 more people per 100,000 people every year.

Installing cool roofs or vegetation can lead to a meaningful reduction in heat deaths by making the daytime weather conditions more tolerable. There are a number of studies estimating the impact of increasing urban reflectivity and vegetative cover on weather conditions. Kalkstein 2012 and Vanos 2013 looked at past heat waves in 4 U.S. cities and modeled the impact of increasing reflectivity by 0.1 (the estimated equivalent of switching about 25 percent of roofs from dark to light colors) and vegetative cover by 10 percent. Though the sample sizes are too small to draw sweeping conclusions, the studies found that cities making these modest changes could shift weather into less dangerous conditions and reduce mortality by 6 percent to 7 percent.

Cooler Cities Are Engines of Economic Growth

The health, air quality, and energy benefits of modest increases in urban roof reflectivity could generate billions of dollars of

An infrared scan of Sacramento, Calif., shows the range of surface temperatures in the area. Source: Lawrence Berkeley National Laboratories.

(Figure 3) An infrared scan of Sacramento, Calif., shows the range of surface temperatures in the area. Source: Lawrence Berkeley National Laboratories.

economic prosperity for our cities. A study of 1,700 cities published in the Journal Nature Climate Change found that changing only 20 percent of a city’s roofs and half of its pavement to cool options could save up to 12 times what they cost to install and maintain, and reduce air temperatures by about 1.5°F (0.8°C). For the average city, such an outcome would generate over a $1 billion in net economic benefits. Best of all, adding cool roofs to between 20 and 30 percent of urban buildings is a very realistic target if existing urban heat island mitigation policy best practices are adopted.

Cool Roof Performance in Cold Climates: In Brief

As positive as cool roofs are for cities in cool climates, they first have to be a high-performing choice for the building itself. What do we know about net energy savings in cool climates with higher heating load? This question was the subject of “There is Evidence Cool Roofs Provide Benefits to Buildings in Climate Zones 4-8” in the November/December 2016 issue of Roofing that summarized the newest science and field studies that show that reflective roofs provide net energy benefits and favorable heat flux impacts on roofs in cold climates. In short, the newest research from Columbia, Princeton and others demonstrates that the size of the “winter heating penalty” is significantly less than many had thought and shows net reductions in annual energy use when cool roofs are used, even with roof insulation levels as high as R48.

Real Cool Roofs in Cold Climates: The Target Survey

It is not just the science that supports the use of reflective roofs in cold climates. The strong and steady growth of cool roofing in northern markets over the last decade or two is also a good indication that reflective roofs are a high-performance option in those areas. For almost 20 years, Target Corporation has installed reflective PVC membranes on nearly all of its stores in the

Studies estimate that modest increases in urban roof reflectivity could generate billions of dollars of economic prosperity for cities. Pictured here is the roof on the Cricket Club in Toronto. Photo: Steve Pataki

Studies estimate that modest increases in urban roof reflectivity could generate billions of dollars of economic prosperity for cities. Pictured here is the roof on the Cricket Club in Toronto. Photo: Steve Pataki

United States and Canada. The membranes are usually installed over a steel deck with no vapor retarder. Target and manufacturer Sika Corporation undertook a field study of 26 roofs on randomly chosen stores located in ASHRAE Climate Zones 4-6 including Connecticut, Illinois, Massachusetts, Michigan, Minnesota, New York, Washington, and Wisconsin. The roofs were 10-14 years old at the time of the survey. None of the 51 total roof sample cuts were made across these roofs showed signs of condensation damage. A more detailed accounting of the study by representatives of Target Corporation and Sika Sarnafil published in Building Enclosure includes this important paragraph from authors Michael Fenner, Michael DiPietro and Stanley Graveline:

“Specific operational and other costs are confidential information and cannot be disclosed. However, it can be stated unequivocally that although the magnitude varies, Target has experienced net energy savings from the use of cool roofs in all but the most extreme climates. Although the savings in northern states are clearly less than those achieved in southern locations, experience over approximately two decades has validated the ongoing use of cool roofs across the entire real estate portfolio. Even in climates with lengthy heating seasons, overall cooling costs exceed heating costs in Target’s facilities.”

It is increasingly clear that installing cool roofs is the definition of “doing well by doing good.” Even in cold areas, a properly built roof system with a reflective surface is a high-performance option that delivers value for building owners while making hugely positive contributions to the neighborhoods and cities they occupy.

Spray Polyurethane Foam and Photovoltaic Roofing Systems

Spray polyurethane foam and photovoltaic systems are increasingly utilized together as
a joint solution for energy savings. With the continued push toward sustainability and growing
movements, like net-zero-energy construction, SPF and PV systems are a logical combined solution for the generation of renewable energy, the conservation of heating and cooling energy, and the elimination of the structure’s dependence on fossil-fuel-consuming electricity sources. Regardless of whether net-zero energy is the end goal, SPF and PV combined in roofing can be quite effective for many structures. Here are some considerations when looking to join these two powerful systems on the roof of a building.

ROOFTOP PV INSTALLATION TYPES FOR USE WITH SPF

Installation of PV systems on SPF roofing will inevitably create additional foot traffic. It is important to protect heavily trafficked areas with additional coating and granules or walk pads.

Installation of PV systems on SPF roofing will inevitably create additional foot traffic. It is important to protect heavily trafficked areas with additional coating and granules or walk pads.


Rooftop PV systems can vary significantly in size. Large-footprint buildings can employ PV systems rated from 50 kilowatts to 1,000 kW or larger while residential rooftop PV systems are commonly 3 kW to 5 kW.

Rooftop PV systems may be installed on racks or adhered directly to the roof surface. When looking to combine PV with SPF, it is generally not advised to adhere or place the PV panels directly onto the roof surface. Solar heat and water can accumulate between the PV and roof coating which could negatively impact coating performance. Moreover, panels applied directly to a low-slope roof will not be properly aligned with the sun to achieve optimal performance.

Non-penetrating rack systems may be placed directly on a rooftop and held in place with ballast. Racks may also be installed with penetrating supports that require flashings. Each type provides advantages and disadvantages. For example, ballasted racks may block water flow and affect drainage while penetrations require leak- and maintenance-prone flashings. SPF is unique in that it easily self-flashes around penetrating supports.

PV EXPLANATION

PV cells are the basic unit used to convert light to electricity. Many PV cells are bundled together to make a PV panel, or module. PV panels are grouped electrically to create a PV string. Depending on the system size, two or more strings are combined to create a PV array.

The dominant type of PV panel used with SPF roofing is cSi, or crystalline silicon. cSi is a typically rigid panel with a glass and metal frame and may be applied, unlike other dominant PV panel types, via rack installation methods.

A PV system includes many components in addition to the panels. Components include racks, rails, rooftop attachment devices, grounding systems, wiring and wiring harnesses, combiner boxes, inverter(s) and connection to the main electrical panel. Components may also include control modules and storage batteries for off-grid PV system installations.

ELECTRICAL SAFETY

Photovoltaic panels must be handled and maintained with caution. Electricity is produced when a single panel is exposed to light; however, because a panel is not part of a circuit, that electricity will not flow until the circuit is complete. A worker may complete the circuit by connecting the two wires from the backside of a PV panel.

When maintaining a PV system, it may become necessary at some point to disconnect or remove an individual panel from a string or an array. The whole system must be shutdown properly as a precautionary measure to prevent shocks from occurring to workers and arcing between electrical connections. This “shutdown” procedure must be followed with precision as part of a lock-out/tag-out program. This procedure is provided by the inverter manufacturer. Under no circumstances should SPF contractors ever disconnect or decommission a PV panel or system unless they are trained and qualified to do so.

HEAT BUILDUP

Photovoltaic panels convert approximately 15 to 20 percent of light to electricity, leaving the remaining unconverted energy to be released as heat. Additionally, PV panels are more effective when their temperature drops. It is for these reasons that the majority of rooftop PV systems are installed to encourage airflow under panels, which reduces the temperature of the panels, improves conversion efficiency and releases heat effectively. Photovoltaic panels installed 4 to 5 inches above the roof will not change the temperature of the roof and, instead, provide shade to the surface of that roof. This additional shade may extend the life of SPF roof coatings.

LOAD

PV panels add weight to a rooftop and this must be factored into the design and installation. Existing structures should be analyzed by a structural engineer to determine if the additional weight of the PV system is acceptable.

Rack-mounted arrays with penetrating attachments are fairly lightweight at 2 to 3 pounds per square foot, and ballasted arrays add 4 to 6 pounds per square foot. However, with the latter, more ballast is utilized at the perimeters and corners of a PV array. Thus, localized loading from ballast may reach as high as 12 to 17 pounds per square foot, which must be considered. Most SPF roofing systems have a compressive strength of 40 to 60 psi.

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A New Report Finds Sustainable Roofs Deliver Millions in Benefits to ‘Roof Aware’ Cities

“Roof Awareness” has come a long way during the years. It used to be that people only thought about their roofs when something went wrong. Building owners then started realizing that making smart choices about the roof could save money on energy costs. Roofs are now seen as essential platforms for cities to meet energy-efficiency and renewable-energy goals, to improve the health and quality of residents’ lives, and to achieve social equity. A new effort to better quantify those benefits and costs shows cities with good roof awareness are reaping millions in economic benefits.

TABLE 1: Summary of cost-benefit analysis results (NOTE: There is no internal rate of return, simply payback, or benefit-to-cost ratio for rooftop PV because we all rooftop PV systems are financed with a PPA [so there is no upfront cost to DGS]).

TABLE 1: Summary of cost-benefit analysis results (NOTE: There is no internal rate of return, simply payback, or benefit-to-cost ratio for rooftop PV because we all rooftop PV systems are financed with a PPA [so there is no upfront cost to DGS]).

With that change in role comes new challenges for evaluating what type of roof makes sense for building owners and cities alike. There are well-developed building models and field studies that give us great insight into how sustainable roofing—that is, reflective, vegetated or solar roofs—saves energy and energy costs. But there is not a single tool that could evaluate all the benefits that accrue from good roofing choices beyond energy savings, such as better health, enhanced air quality, greater stormwater management and improved social conditions. Until now, that is.

A recently released report—the “Affordable Housing Smart Roof Report”—from Washington, D.C.-based Capital E, a firm dedicated to accelerating the transition to a low-carbon economy, now allows city officials and owners of affordable housing developments to see and calculate the full lifetime costs and benefits of roof decisions. “This is the first model that helps the user puta dollar value on the various benefits of sustainable roofing options. We see this as a great tool for contractors looking to quantify the full benefits of sustainable roofing for their potential clients. It will also help city officials to enact policies that recognize the value of smarter roofing that may not be directly visible on the building owner’s books,” says Keith Glassbrook, a Capital E senior analyst and one of the lead developers of the new model.

TABLE 2: Present value summary of costs and benefits for the three technologies on all low-slope DGS roofs (NOTE: All PV is financed with a PPA so there is no upfront cost to DGS; results may not sum due to rounding).

TABLE 2: Present value summary of costs and benefits for the three technologies on all low-slope DGS roofs (NOTE: All PV is financed with a PPA so there is no upfront cost to DGS; results may not sum due to rounding).

Building the Tool

Rather than reinventing the wheel, Capital E identified existing tools, models and methods from the huge base of existing science for each item in its cost-benefit analysis. The model integrates these individual, detailed components into a form that is accessible and easy to use for non-scientists and that provides straightforward results in dollars per square foot.

The model is an extension of an analysis undertaken for the Washington, D.C., Department of General Services (DGS) as part of its Smart Roofs Initiative. The initiative is designed to help Washington achieve its aspirations to become the greenest, healthiest, most equitable city in the U.S. by using the roofs of city-owned buildings more thoughtfully. DGS owns and controls more than 400 buildings in Washington, including office buildings, schools and hospitals. The city is using this portfolio (28 million square feet of buildings with approximately $62 million in annual energy expenditures) to drive deep improvements in energy efficiency and achieve other objectives.

Like a growing number of cities, Washington, D.C., is committed to using its roofs to deploy photovoltaic panels to generate electricity, cool roofs to reflect sunlight and reduce unwanted heat gain in summer, and green roofs to cut stormwater runoff that results in water pollution and requires construction of expensive water-treatment plants and other grey infrastructure. Tommy Wells, a former councilmember and current director of the District Department of the Environment, summarized the reasons in the Smart Roof cost-benefit report’s press release: “Past research shows that ‘smart’ roof strategies that reduce extreme temperatures in buildings can literally save lives. This new report provides additional justification for cool, green, and solar roofing solutions by showing that they also make compelling financial sense as we work to make D.C. a healthier and more sustainable city.”

Washington has been among the most advanced cities in the nation in deploying sustainable roof technologies. But because there was no established methodology for quantifying the full cost and benefits—including health benefits—for any of these technologies, Washington to date had not been able to quantify the full costs and benefits of these roof choices or compare the merits of each to make informed decisions about which technologies to deploy and at what scale. The analysis undertaken by Capital E to remedy this issue concluded that DGS’ Smart Roofs program can deliver between $47 and $335 million in benefits to the city over 40 years, depending on the roof technology chosen.

More Analysis

A parallel analysis was funded by the New York-based JPB Foundation, which seeks to enhance the quality of life in the U.S. by creating opportunities for those in poverty, promoting pioneering medical research, and enriching and sustaining the environment. JPB Foundation launched its analysis based on the success of this initial analysis by DGS. This time, the model was adapted to evaluate actual affordable-housing buildings in Baltimore; Los Angeles; Philadelphia; and Washington, D.C. The sample buildings, which were part of the National Housing Trust, Washington, or Columbia, Md.-based Enterprise Community Partners Inc.’s portfolios, included steep- and low-slope roofs, high- and low-rise structures, as well as some attached row houses. The project team for this study included the National Housing Trust; Washington-based American Institute of Architects; Washington-based Global Cool Cities Alliance; Enterprise Community Partners; and U.S. Green Building Council, Washington. In each city and building type evaluated, the model found sustainable roofs would generate more benefits than they cost (first cost and maintenance) and would, in some cases, have an immediate payback.

The results were variable by building and city but they confirmed that sustainable roofing was the superior economic choice compared to traditional dark roofs in the cities studied.

The JPB Foundation analysis shows there is no one-size-fits-all solution to maximize value with sustainable roofing. For example, green roofs made the most sense in Washington, D.C., because of the city’s stormwater rules. On the building in Baltimore, cool roofs were the best choice. The results were variable by building and city but they confirmed that sustainable roofing was the superior economic choice compared to traditional dark roofs in the cities studied.

A second phase is currently underway by JPB Foundation to extend the model to large areas of cities to capture the impact of sustainable roofs at a community scale, as well as other technologies, such as reflective pavements, and to better quantify some of the social benefits of cooler, more enjoyable surroundings.

Research Helps Industry Organizations Conclude Ballasted Roofs Provide Energy Savings

During the last decade, the roofing industry has been increasingly impacted by two strong forces: first, rising energy prices with no real end in sight, and, second, increasingly stringent building codes and regulations, designed to limit emissions, reduce energy use and mitigate the impact of urban heat islands.

The first definitive study to measure the energy-saving potential of ballasted roofs was done at Oak Ridge National Laboratory, Oak Ridge, Tenn., in 2007.

The first definitive study to measure the energy-saving potential of ballasted roofs was done at Oak Ridge National Laboratory, Oak Ridge, Tenn., in 2007. PHOTO: EPDM Roofing Association

The industry response has also been two-fold: In some instances, new products have been created, such as lower VOC adhesives, primers and sealants, self-adhering membranes and a wider variety of reflective membranes. At the same time, roofing professionals have taken a close look at some of the products that have been in use for a generation. Using rigorous science, they have tested these tried-and-true products to see how they measure up against the new standards. And in many cases, they’ve found that products that have been in use for decades are delivering great results in this new, energy-sensitive environment. Case in point: ballasted roofing, which has been available since the early 1970s, is turning out to be a great choice to meet 21st century needs.

2007 Study

The first definitive study to measure the energy-saving potential of ballasted roofs was done at Oak Ridge National Laboratory, Oak Ridge, Tenn., in 2007. Andre Desjarlais, ORNL’s group leader of Building Envelope Research, and his colleagues had just completed work in which “we had done a fairly substantial comparison of different cool roof technologies, both membrane types, as well as coatings,” Desjarlais says. At the request of EPDM manufacturers, working together at the newly founded EPDM Roofing Association (ERA), Bethesda, Md., as well as manufacturers within Waltham, Mass.-based SPRI, Desjarlais designed and implemented a second study to assess the performance of ballasted roofing. “We undertook a study to effectively expand what we had done earlier on coatings and membranes,” he says.

Other factors also encouraged ORNL to generate data about ballasted roofing. The California Energy Commission, Sacramento, had just revised its codes, essentially defining roofs with high reflectance and high emittance as the only choice of roofing membranes that would deliver high energy savings. Desjarlais believed this definition of a “cool roof” might be inaccurately limiting roofing choice by excluding other roofing materials, such as ballasted roofs, that would deliver comparable savings.

The California Energy Commission, Sacramento, had just revised its codes, essentially defining roofs with high reflectance and high emittance as the only choice of roofing membranes that would deliver high energy savings.

The California Energy Commission, Sacramento, had just revised its codes, essentially defining roofs with high reflectance and high emittance as the only choice of roofing membranes that would deliver high energy savings. PHOTO: EPDM Roofing Association

In addition, in Chicago, a new Chicago Energy Code was adopted as early as 2001 “with high reflectivity and emissivity requirements that limited severely building owners’ and managers’ roof system choices”, according to a paper presented in 2011 by Bill McHugh of the Chicago Roofing Contractors Association. At the roofing industry’s request, a reprieve was granted, giving the industry until 2009 to come up with products with a reflectivity of 0.25.

Faced with that 2009 deadline, the Chicagoland Roofing Council, Chicago Roofing Contractors Association and Rosemont, Ill.-based National Roofing Contractors Association began in 2001 to conduct research on products that would help to meet the city’s goal of creating a workable Urban Heat Island Effect Ordinance while giving building owners a wider choice of roofing products. As part of their effort, the industry coalition turned its attention to the energy-saving qualities of ballasted roofing and coordinated its work with the research at ORNL.

Desjarlais points out the concept of thermal mass having energy benefits has been accepted for years and has been a part of the early version of ASHRAE 90.1. “Thermally massive walls have a lower insulation requirement, so there was industry acceptance of the fact that using mass is a way of saving energy,” he says. “But we had a hard time translating that understanding from a wall to a roof. Whether you do that with a concrete block or a bunch of rocks doesn’t really matter. The metric is no different. Roofs or walls.”

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EPDs Provide a New Level of Environmental Transparency to Building Products

The sustainability movement has impacted the building industry in many ways. Today’s architects, owners and occupants have much greater expectations for the environmental performance of the buildings they design, operate and dwell in. Part of this expectation is focused on the components that make up the building. For example, did the wood come from responsibly harvested forests? Is the metal made of recycled material? Do the paint and interior finishes contain volatile organic compounds (VOCs)?

An Environmental Product Declaration, or EPD, is developed by applying a Product Category Rule, or PCR. PCRs are developed, maintained and warehoused by program operators. Examples of program operators include ASTM, CSA, ICC-ES, Environdec and UL Environment. Program operators also verify that an EPD and its associated life-cycle assessment conform with ISO 14025 and the ISO 14040 series. PCR development is commonly a collaborative effort between industry associations, manufacturers, and/or others.

An EPD is developed by applying a Product Category Rule. PCRs are developed, maintained and warehoused by program operators. Examples of program operators include ASTM, CSA, ICC-ES, Environdec and UL Environment. Program operators also verify that an EPD and its associated life-cycle assessment conform with ISO 14025 and the ISO 14040 series. PCR development is commonly a collaborative effort between industry associations, manufacturers, and/or others. IMAGE: Quantis US

Information technology has encouraged and facilitated this increased demand for in-depth data about building components and systems. People have become accustomed to being able to gather exhaustive information about the products they buy through extensive labeling or online research.

In response to the growing demand for environmental product information, building component manufacturers have begun rolling out environmental product declarations, or EPDs.

It’s a term now commonly heard, but what are they? EPDs are often spoken in the same breath as things like LCA (life-cycle assessment), PCRs (product category rules) and many other TLAs (three-letter acronyms). The fact is they are all related and are part of an ongoing effort to provide as much transparency as possible about what goes into the products that go in and on a building.

“An EPD is a specific document that informs the reader about the environmental performance of a product,” explains Sarah Mandlebaum, life-cycle analyst with Quantis US, the Boston-based branch of the global sustainability consulting firm Quantis. “It balances the need for credible and thorough information with the need to make such information reasonably understandable. The information provided in the document is based on a life-cycle assessment, or LCA, of the product, which documents the environmental impacts of that product from ‘cradle to grave.’ This includes impacts from material production, manufacturing, transportation, use and disposal of the product. An EPD is simply a standardized way of communicating the outcomes of such an assessment.”

The concept of product LCAs has been around for some time and has often been looked at as a way of determining the sustainability of a particular product by establishing the full scope of its environmental footprint. The basic idea is to closely catalog everything that goes into a product throughout its entire life. That means the energy, raw materials, and emissions associated with sourcing its materials, manufacturing it, transporting it, installing it and, ultimately, removing and disposing of it. In the end, an LCA results in a dizzying amount of data that can be difficult to translate or put in any context. EPDs are one way to help provide context and help put LCA data to use.

“The summary of environmental impact data in the form of an EPD can be analogous to a nutrition label on food,” says Scott Kriner, LEED AP, technical director of the Metal Construction Association (MCA), Chicago. “There is plenty of information on the label, but the information itself is meaningless unless one is focused on one area. An LCA determines the water, energy and waste involved in the extraction of raw materials, the manufacturing process, the transportation to a job site and the reclamation of waste at the end of the useful life of a product. With that data in hand, the various environmental impact categories can be determined and an EPD can be developed to summarize the environmental impact information.”

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The Growing Solar Industry Demands Certified Solar Roofing Professionals Complete Installations

During my 35 years in the roofing industry and seven years as a solar photovoltaic (PV) professional, I have noticed several issues that often arise during rooftop PV installations.

  • It is important to spend time with customers, ensuring they are educated and informed prior to choosing a PV system for their project.
  • Installers must understand and implement proper safety practices for rooftop work. Often, roof-mounted PV installations are best completed by individuals who have experience with the hazard exposures of roofing environments.
  • Quality products that fulfill the applications’ needs and specifications must be installed.
  • Attention to installation details is often overlooked, yet is a fundamental aspect of successful solar installations.
  • Customer satisfaction is best achieved with frequent communication, like regular progress reports and follow-ups.
  • The dynamics of today’s solar market require diversification, qualification and excellent service to meet PV project demands.

The Certified Solar Roofing Professional (CSRP) credential is overseen by Rosemont, Ill.-based Roof Integrated Solar Energy, or RISE. RISE evaluates and certifies solar roofing professionals for knowledge about critical roof system construction and maintenance practices necessary to support successful rooftop solar-energy installations. Achieving the CSRP credential matched our company philosophy of ensuring a roof-mounted PV installation will not adversely affect a roof system’s performance.

As a member of the first group who earned the CSRP credential, I clearly understood the potential benefits to my company and, more importantly, what this would mean to my customers. I believe becoming a RISE CSRP, and being recognized by an independent organization, provides credibility and a competitive advantage in the growing and demanding PV marketplace. The additional training and education needed to achieve and maintain the CSRP credential is specific to the related tasks involved in rooftop solar installation.

The CSRP credential helps assure homeowners, business owners, architects and developers that their new PV project is up to the task. These owners expect and deserve to know that all aspects of the project (solar, roofing, electrical, design and several other important factors) are being addressed to achieve a successful integration of their PV and roofing systems. By choosing a CSRP, they are assured their projects will be handled by the most capable professionals.

Once earned, there are several requirements to maintain the CSRP credential. These include continuing education to keep up with the latest in PV and roofing technologies, as well as engaging in other professional activities, such as presenting at industry trade shows or other public forums.

Meeting these requirements continues to enhance my career. It also affirms to our customers that I am well-informed about the fast changing solar industry, including best business practices, application methods and technologies. Therefore, I’m very capable of meeting their expectations and demands. Maintaining my CSRP credential also helps me contribute more directly to my company’s success by keeping other employees informed.

There are a lot of so-called solar professionals out there who do not have the proper credentials, experience or knowledge to properly install a PV system. They may inadvertently negatively affect a customer’s roof performance and service life, as well as the performance of the PV system.

We recently have experienced an increase in calls for roof repair services. When we first visit these projects, it is immediately evident an installer failed to properly integrate the roof, waterproofing and electrical details when installing the solar PV system. Unfortunately, I have seen leaks, fires and inoperable systems—all of which harm the roofing and solar industry’s reputation. A CSRP could have helped address these issues for the customer upfront and thus avoided incurring additional expenses above the original installation, as well as other economic losses from an inoperable PV system.

Calling a CSRP puts you on the right path to a quality installation. Often, it is said good business practices go a long way, and I have found this to be spot on. I have always been proud of the work my company provides its customers. And earning my CSRP credential fostered a stronger desire to reach for higher standards in the roofing and solar industry. I am looking forward to providing rooftop PV services and representing the CSRP program for many years to come. I know that by being a CSRP, I am ensuring my customer’s roof installations will continue doing their primary job: protecting buildings from the elements.

Learn More

Become a Certified Solar Roofing Professional today!

Roofing Manufacturers and Contractors Embrace Recycling

In the early 2000s, as the green-building movement reached its tipping point, the roofing industry’s contributions to sustainability focused on increasing energy efficiency, improving long-term durability and addressing the heat-island effect. In the years since, significant strides have been made in all three of these areas for commercial and residential buildings.

In recent years, increasing attention has been given to the benefits and challenges of recycling roofing materials at the end of their useful life. This is no trivial task: Owens Corning estimates asphalt shingles alone comprise up to 5 percent of building-related landfill waste. This doesn’t take into account other roofing materials, including EPDM, thermoplastic PVC and metal.

Not surprisingly, rising removal costs, coupled with the growing demand in some areas of the country to legislate landfill content, are putting pressure on contractors and building owners to seek alternatives to traditional roof construction scrap and tear-off disposal methods.

In response, greater numbers of roofing manufacturers and contractors are driving strategies to avoid the landfill. A general review of emerging trends across the roofing industry suggests manufacturers and contractors increasingly are turning to recycling to steer these materials from the waste stream.

Steel is the most recycled material in building construction today. PHOTO: STEEL RECYCLING INSTITUTE

Steel is the most recycled material in building construction today. PHOTO: STEEL RECYCLING INSTITUTE

METAL

Metal roofing’s sustainable attributes are significant. Industry experts cite its ability to improve a building’s energy efficiency, and metal today contains anywhere from 25 to 95 percent recycled material.

On its website, the Chicago-based Metal Construction Association (MCA) encourages installing metal roofing directly over an existing roof, thus eliminating the need to dispose of the original materials. But when an older metal roof or new-construction debris must be removed from a site, contractors and owners in most regions of the country can quickly identify scrap yards that take metal.

“Steel is the most recycled material in building construction today,” says MCA Technical Director Scott Kriner. “There’s an infrastructure that supports it, and metal in general is virtually 100 percent recyclable.” Kriner notes MCA supports recycling as part of the metal industry’s overall commitment to environmental sustainability and transparency in business.

PVC

PVC has been used in roofing systems since the 1960s, and the post-consumer recycling of roof membranes began in North America in 1999—a nice symmetry when one considers roofs in terms of 30-year life cycles.

In general terms, the recycling of PVC roofing is a relatively straightforward process. The material is sliced into long strips, rolled up, lifted off the roof and transported to a recycling center. Recyclers run the PVC through a conveyor system, where fasteners and other metal objects are removed.

Initially, the recovered membrane was ground into powder for reuse in molded roof walkway pads. More recently, some manufacturers have been incorporating a granulated form into new PVC roofing membranes, exclusively on the backside to avoid aesthetic issues with color variations. The first installations of membrane produced with post-consumer recycled composition occurred in the mid-1990s. So far, its field performance has matched that of PVC roofing produced with virgin raw materials.

The Vinyl Institute, Alexandria, Va., says close to 1 billion pounds of vinyl are recycled at the postindustrial level yearly. “The vinyl industry has a history of supporting recycling,” the institute reports on its website, “and this effort continues as companies, alone and through their trade associations, expand existing programs and explore new opportunities to recover vinyl products at the end of their useful life.”

EPDM

Ethylene propylene diene terpolymer is used extensively on low-slope commercial buildings. Yet even this durable synthetic rubber membrane must eventually be replaced, and today recycling is a viable option.

The removal process generally involves power-vacuuming off the stone ballast, where present, to expose the EPDM membrane below. The membrane can then be cut into manageable squares, which are folded and stacked on pallets, loaded onto a truck and transported for recycling. The recycler grinds it into crumbs or powder, depending on the end use. A growing number of recycling centers nationwide now handles EPDM.

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Coating a Roof? Don’t Forget Fire Ratings

Fire tests are one of the most important system tests for roof coatings, and it is essential when specifying and applying a coating over an existing roof in a maintenance or repair setting to ensure the roof system’s fire rating is not negatively affected.

TEST METHODS FOR FIRE TESTS

The International Building Code (IBC), first published in 2000, brought together several regional codes into one central, national code and facilitated the acceleration of code adoptions across the U.S. Today, most of the U.S. follows a statewide adoption process for the IBC for Roof Assemblies and Rooftop Structures; some areas do not, which can make code enforcement tricky. Some areas still follow local adoption and may refer to older versions of the code instead of the most current 2012 IBC.

According to the most recent IBC, roof assemblies and coverings are divided into classes A, B, C or “Nonclassified” and are tested in accordance with UL 790 or ASTM E 108. These tests measure the spread of flame, recording whether the material you put on the roof will cause the flame to spread too far on the roof. The UL 790 inaugurated modern fire tests about 100 years ago and, as such, incorporates a century of data and history about roof coatings that may broaden the reach of what certifications the test provides.

“Many see UL 790 as the preferred fire test,” notes Steve Heinje, technical service manager with Quest Construction Products LLC. “It is interesting to note the ASTM E 108 test is deemed by the code requirements an equivalent test.” The ASTM E 108 is a consensus version of UL 790 and can be run by any qualified and accredited test laboratory. Many test laboratories, such as FM Approvals, conduct testing using ASTM E 108.

COMPONENTS OF FIRE TESTING

The roof coating is just one component in the fire rating of a roof assembly; other components include slope, the coating substrate, whether the roof deck is combustible and whether the roof is insulated. These factors, taken together, will determine the roof system’s fire rating.

SLOPE
Although there are exceptions, most fire ratings are done for slopes of under 3/4 inch for commercial roofs, and coatings tend to be recommended for application to a roof with 2 inches or less slope. Slope is an important factor to consider because special coatings may be needed for high slope transitions.

SUBSTRATE
The substrate or membrane type is another vital component of fire testing because the substrate to which the coating is applied could affect the flammability of the roof system. When coating over an existing roof, one should note what existing roofing substrate is being coated over—whether it’s BUR, mod bit, concrete, metal, asphalt or another type of substrate.

COMBUSTIBLE VS. NON-COMBUSTIBLE ROOF DECK
Most coatings are tested over noncombustible decks, but additional and challenging tests are required for the use of combustible decks. It is much more difficult to achieve a Class A rating when covering a wood deck.

INSULATION
Again, it is important to note the materials of the existing roof being coated because these components can affect the flammability of the roof system. Polymeric insulations often reduce the allowable slope for a given system.

PROPER APPLICATION OF THE ROOF COATING

Another significant consideration is that the coating is applied at the appropriate thickness and rate.

“One big thing out of the coating manufacturer’s control is that the applicator uses the recommended or test-required thickness and/or rate at the point of application,” points out Skip Leonard, technical services director with Henry Co. Proper application encompasses parameters, such as the final dry-film thickness, the use of granules or gravel, use of reinforcements and even the number of coats. Accounting for these details is an integral part of installing a rated system.

Once assembled, the roof covering will be granted a Class A, B or C rating by approved testing agencies, typically through UL 790 or ASTM E 108, depending on how effective the roof proves to be in terms of fire resistance. Rated coating solutions exist for just about any existing roof system recover or coating application and often can achieve a Class A rating.

Learn More
Visit the Roof Coatings Manufacturers Association website to locate a roof-coating manufacturer who can help you choose a roof coating most appropriate for your roof system. For more information about roof-coating fire ratings, check out FM Approval’s RoofNav online database for up-to-date roofing-related information or the UL Online Certifications Directory.

Energy-efficient Cool-roof Legislation: Creating Jobs and Reducing Energy Costs

Building on two roofing trends—higher thermal performance and cooler roofs in hotter climates—that have policymakers and architects seeing eye to eye, energy-efficient cool-roof legislation offers a significant opportunity to increase building energy efficiency and create jobs. Known in the last Congress in the Senate as S. 1575, the Energy-Efficient Cool Roof Jobs Act, and in the House of Representatives as H.R. 2962, the Roofing Efficiency Jobs Act, the legislation is scheduled to be reintroduced this spring.

The intent of the legislation is to encourage improvement in the thermal performance of existing roofs and, where appropriate in the designer’s judgment, encourage the use of a white or reflective roof surface in hotter climates. This is a clear win-win for the environment and building owners in terms of reduced energy costs and reduced pollution associated with energy consumption.

energy efficiency

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SIGNIFICANT SAVINGS lie within the commercial roofing sector, where more than 50 billion square feet of flat roofs are currently available for retrofit, 4 billion of which are typically retrofitted each year. The legislation would provide a 20-year depreciation period (instead of the current 39 years) for commercial roofs that meet minimum R-values that are significantly higher (requiring more insulation) than those required under state and local building codes and that have a white or other highly reflective surface. This change would correct an inequity in the current depreciation system (the average life span of a low-slope roof is only 17 years). By providing this incentive, the federal government would allow building owners and architects to decide whether the combination of thermal insulation and reflective roofs are appropriate for a given climate.

The required R-values under the proposed legislation are identical to the prescriptive requirements found under ASHRAE 189.1-2011, “Standard for the Design of High-Performance, Green Buildings Except Low-Rise Residential Buildings”. This legislation would be limited to retrofits of existing low-slope roofs and would not be available to new buildings. The cool roof requirement would only apply to buildings in ASHRAE Climate Zones 1 through 5, which covers approximately the area of the country from Chicago and Boston south. Roofs may qualify for the depreciation in zones 6, 7 and 8 but would not need a cool surface. View a map of the ASHRAE Climate Zones.

According to the U.S. Department of Energy’s Annual Energy Review, 2011, buildings account for 19 percent of the nation’s total energy usage and 34 percent of its electricity usage. Policies directed at commercial buildings are important to improving the economy, reducing pollution and strengthening energy efficiency. Although the country has over time maintained a steady pace in improving energy efficiency, a huge potential still exists, especially for commercial buildings. A wide range of credible estimates are available that point to this potential for cost-effective energy-efficiency improvements (see the graph).

THIS PROPOSED legislation complements the approaches taken in more comprehensive energy-efficiency proposals by focusing on the roof, which is the only building-envelope component that is regularly replaced but rarely upgraded to address energy and other environmental impacts.

Most buildings were constructed before building energy codes were first developed in the mid-1970s, or buildings were constructed under relatively weak codes, so these older, under-insulated roofs offer an important opportunity for increased energy savings. During the next 17 to 20 years, most of the weatherproof membranes on all commercial roofs will be replaced or recovered, which is the most cost-effective time to add needed insulation.

By accelerating demand for energy-efficient commercial roofs, the proposed legislation would:

    ▪▪ Create nearly 40,000 new jobs among roofing contractors and manufacturers.
    ▪▪ Add $1 billion in taxable annual revenue to the construction sector.
    ▪▪ Save $86 million in energy costs in the first year.
    ▪▪ Eliminate and offset carbon emissions by 1.2 million metric tons (equal to emissions of 229,000 cars).

THE LEGISLATION has the support of the Polyisocyanurate Insulation Manufacturers Association; National Roofing Contractors Association; Alliance to Save Energy; American Council for an Energy-Efficient Economy; Associated Buildings & Contractors Inc.; Building Owners and Managers Association International; United Union of Roofers, Waterproofers and Allied Workers; and several more construction industry associations.

When Sens. Cardin and Crapo reintroduce the Energy-Efficient Cool Roof Jobs Act, they hope it will influence the future debate about tax and energy policy. Although consideration of tax reform has stalled for the moment, when Congress returns to this issue it will be a golden opportunity to consider ideas for reforming cost-recovery periods and removing the disincentives that overly long depreciation schedules currently place on building energy-efficiency improvements.

From Green to Blue: Making Roof Systems Sustainable in Urban Environments

Municipal storm-water managers historically have focused on controlling runoff from ground-level impervious surfaces, such as roadways, sidewalks and parking areas. However, the next frontier in storm-water management is rooftops. In urban storm-water management, roofs are part of the problem and potential solution. An exciting new technology to control rooftop runoff is known as blue roofs. Over the next several years, New York City alone will spend several billion dollars on green infrastructure solutions to address its storm-water-control problem, and blue roofs will be a key part of these efforts.

Blue-roof trays are held in place with stone ballast and hold up to 2 inches of water. The tray systems resulted in a 45 percent reduction in roof runoff during rainfall events in a New York pilot project.

Blue-roof trays are held in place with stone ballast and hold up to 2 inches of water. The tray systems resulted in a 45 percent reduction in roof runoff during rainfall events in a New York pilot project.

Blue Roofs

The roofing industry has become very familiar with the use of vegetated, or green, roofs. The vegetative layer grown on a rooftop provides shade and removes heat from the air through evapotranspiration, ultimately reducing temperatures of the roof surface and the surrounding air. By reducing the heat-island effect, these buildings require less energy to cool in the summer and use fewer natural resources (oil or other fuel) in the process.

However, an even newer and less-well-known sustainable technology applicable to roofs is the blue roof. A blue roof temporarily stores rainwater in any of a number of types of detention systems on the roof. They are most applicable and provide the most benefit in highly urbanized cities that are serviced by combined sewers. Combined sewers handle sewage and rainwater runoff from roofs, streets and other impervious surfaces. On dry days, these combined sewers can easily handle the amount of sewage flowing through them to the local treatment plant. However, on days with heavy rain, these combined systems can easily overflow with rainwater and raw, untreated sewage. This combined sewer overflow, or CSO, can flow into local sensitive receptors, like streams, ponds and oceans, contaminating the natural resources and killing fish and other wildlife dependent on them.

The beauty of blue roofs is they can store much of this rainwater during and immediately after a rainstorm, temporarily preventing it from reaching the sewer system. In this way, CSOs are minimized and local natural resources are protected. When the storm is over and the sewer system has the capacity to handle it, the blue-roof retention materials are designed to slowly release the stored rainwater back into the storm-drain system.

This blue roof in New York uses a check dam to retain storm water.

This blue roof in New York uses a check dam to retain storm water.

NYC Pilot Program

Our firm, Geosyntec Consultants, along with environmental engineers Hazen and Sawyer and HydroQual and water-management firm Biohabitats, designed and implemented a groundbreaking blue-roof system in New York. The New York City Department of Environmental Protection (NYCDEP) retained the team to implement a sustainable green infrastructure retrofit pilot program to demonstrate how rooftops can reduce the frequency and volume of CSOs in the city. The objective was to design and install storm-water controls to quantify the benefits of sustainable approaches as a viable solution to reduce storm-water flows to the city’s CSO system. Rainfall of less than 1/2 inch can overload the system and result in untreated discharges. The use of sustainable green infrastructure, like blue roofs, to reduce storm-water inputs to the combined system is one of many approaches New York City is considering to help solve this problem.

Geosyntec’s role on the team was to design several storm-water pilot studies, including blue roofs. Our blue-roof designs included installing risers on rooftop outlets that would result in ponding of water around the outlets, small dams on the roof surface using check dams of angle-iron to create ponding and the most successful technique—blue-roof trays. We developed specially designed trays, held in-place with stone ballast, to hold up to 2 inches of water. The tray systems resulted in a 45 percent reduction in roof runoff during rainfall events. If blue-roof trays were installed on all roofs in an entire drainage area to a CSO, the results would be significant in solving the CSO problem. In addition, trays are more practical because they can be spaced around existing equipment on roofs and moved during repairs and maintenance of other rooftop systems.

Geosyntec Consultants designed a blue roof that included installing risers on rooftop outlets that would result in ponding of water around the outlets.

Geosyntec Consultants designed a blue roof
that included installing risers on rooftop outlets that would result in ponding of water around the outlets.

Roof-system Protection

Protecting the integrity of a roof membrane is an important consideration for roofing and building contractors that are considering installing a blue roof. Blue-roof-tray systems offer the best protection because they rest on top of existing membranes and ballast systems and do not result in any membrane perforations that require additional waterproofing. Other blue-roof systems, like check dams or new drain inserts, may require additional waterproofing. The bottom line is if the roof membrane is old, compromised or currently leaking, any type of blue roof would be problematic until a new membrane is installed.

In addition, during the pilot projects, we took great care to inspect and test the roofs for load-bearing support—a step that should be conducted for all blue and green roof systems.

As we look to the future, roofs in urban areas will most definitely become a major part of the storm-water solution, and blue-roof technologies will evolve to become a common practice.

Learn More

NYCDEP has posted information about blue roofs and other urban green infrastructure for CSO control on its website.
The U.S. Green Building Council offers an online course about blue roofs for storm-water management.

PHOTOS: Geosyntec Consultants