White Roofs

Cutting Costs at the Top

By: Tom Gallivan

  Factory executives and plant managers have always looked for ways to contain expenses and make their operations run more profitably — it’s part of the job, and a significant one at that.  But now, with energy costs at an all-time high, reducing expenditures associated with power consumption has become a matter of survival for some maquilas.

  Whether natural energy resources have dwindled or are merely being held back is a matter of debate.  Regardless, the effort to increase the supply rests in the hands of geologists and politicians and is a process energy users may be relatively powerless to influence.  What business owners and operators can do to alleviate their energy demands is use less of it. 

  Industrial companies, particularly those in hot climates where air conditioning costs are primed to explode in the years ahead, must employ creative means of conserving power in order to keep expenses in check.  Installation of a white or light-colored roof is a strategy that is long on upside and has gained considerable momentum among owners and operators of commercial structures — particularly maquilas.

Why white?

  Keeping the heat that is generated by the sun’s rays outside a building is one way to maintain lower temperatures in the structure’s interior, and that’s exactly the theory behind, and function of, a white roof. 

  It’s well known that white objects do a good job of reflecting light, while darker objects are light — and heat — absorbing.  This phenomenon is as true of roof surfaces as it is of shirts and car interiors.  Traditional black roofs fashioned of black rubber, asphalt or other dark materials are light absorbers, transmitting the sun’s heat through their surface and into the building below.  Conversely, a white or light-colored roof such as Stevens EP, will reflect a far greater percentage — up to 80 percent — of the sun’s rays, thereby absorbing and transmitting less heat and keeping the building significantly cooler. 

  Of course in any climate, but particularly warmer ones like Mexico’s, a building with a cooler interior will require less energy and expense to maintain at a comfortable temperature than one in which heat is leaking in through the ceiling.  That’s why, with a white roof, companies are being both truthful and literal when they say they’re cutting costs from the top down.

  Many American state and federal agencies and institutions have focused their efforts on energy usage and conservation in recent years.  In particular, they have evaluated the impact of white roofing systems and found that their ability to reflect light and heat can have a dramatic effect on the reduction of power consumption in warmer weather, specifically the power used for generating air conditioning.

  For instance, the U.S. Environmental Protection Agency has determined that black roofs can be up to 100 degrees (F) hotter than reflective white surfaces.  The EPA found that, by reflecting up to 80 percent of the sun’s rays (and the heat they generate), a light-colored roof system can reduce a building’s peak cooling demand by as much as 15 percent.  (According to the EPA estimates, nearly $40 billion — about one-sixth of U.S. electricity expenditures — is spent each year on air conditioning.)

  The EPA, U.S. Department of Energy and the states of Georgia and California are just a few of the agencies that have created programs and/or legislation designed to encourage or mandate the use of energy-efficient white roofs.  Their actions have included:

  •The EPA’s Energy Star Roof Products program, through which roofing materials meeting the agency’s rigorous specifications for solar reflectivity and reliability carry an Energy Star label.

  •Increased funding of projects calling for white roof installations by the U.S. Department of Energy, which is taking an increasingly assertive posture in rewarding conservation-minded organizations.

  •The California Cool Roofs Retrofit Program, which offers incentives ranging from $.05 to $.15 per square foot (depending on R-value) to California companies and schools that install reflective roofs by the end of the year 2001.

  •The Georgia White Roofing Amendment, which requires building roofs to meet threshold levels of reflectivity and emissivity (which measures a material’s ability to radiate heat from its surface), thereby encouraging the installation of reflective roofing membranes.

  In addition, several trade associations, including the American Society of Heating, Refrigeration and Air Conditioning Engineers (ASHRAE) and the American Society of Testing and Materials (ASTM), have formally recognized the energy- and cost-saving benefits of white roofing materials by establishing standards and measurements for heat absorption and/or sun reflectivity. 

Urban heat islands

  In recent decades, the use of dark construction materials and the lack of shade trees in cities and other population centers have contributed to the formation of areas known as urban heat islands.  This phenomenon, which accounts for cities being up to 12 degrees hotter and generating far more ozone pollution than the surrounding countryside, is an enormous factor in warmer countries like Mexico, where high temperatures and smog levels already pose serious health and safety risks.

  Not surprisingly, urban heat islands continue to be the subject of a growing body of research.  Dr. Ernesto Jáuregui of the Center for Atmospheric Sciences at the National University of Mexico (UNAM) has studied the phenomenon in his country’s largest urban areas throughout the 1990s, concluding that Mexico City and Guadalajara are among the municipalities experiencing a pronounced Urban Heat Island effect.  In the U.S., Lawrence Berkeley National Laboratory (LBNL), a government facility operated by the University of California at Berkeley for the U.S. Department of Energy, estimates that, because of urban heat islands, the city of Los Angeles uses up to an additional 1.5 gigawatts of power annually, costing the city’s ratepayers about $100 million per year.

  Researchers believe that the use of white roofing membranes, which many municipalities now encourage or require owners of new construction to use, would play a significant role in reducing the effects of the urban heat island.  LBNL studies approximate that, if all the buildings in Los Angeles had cool roof systems, the city would realize about $500 million annually in energy and smog savings.

  In addition to their ability to reflect the sun and its heat, white roof systems boast many other advantages over traditional black roofing materials, while suffering no disadvantages by comparison.  Many white single-ply roofing membranes, like Stevens EP, are as easy to install and maintain as they are attractive and energy-efficient.

  Today’s leading white roof systems feature hot-air-welded seams, which can be made stronger than the membrane itself and provide exceptional durability and weather-resistance.  White single-ply membranes are also up to 50 times lighter than ballasted roofing alternatives, which means they can often be applied directly over existing roof surfaces, significantly lowering re-roofing costs.  The light weight of single-ply membranes can also translate into substantial savings on structural steel in new construction.  

  Another reason architects and specifiers so frequently specify single-ply roofing materials is that these membranes can be attached to virtually any type of building design, from those with relatively flat or low sloped roofs to those with higher slopes, including domes, saw tooths, and barrel roofs. 

  Finally, white single-ply membranes, unlike white roofing coatings, stay white for the life of the roofing system, and usually come with long-term (15 or more years) warranties.

  Around the world, white roofing solutions have enjoyed a long and proven history in industrial and commercial applications.  Many types of structures — from manufacturing facilities and school buildings to retail complexes and sports stadiums — have gone white on top, opting for energy-efficient roofing that offers myriad additional benefits.

  In the United States, numerous business concerns have turned to white roofing in the past decade.  These include:

  •Mercedes-Benz, whose Alabama-based M-Class assembly plant deployed more than one million square feet of Stevens EP white roof membrane to help reduce the energy load on rooftop chiller units.

  •Helen of Troy, an El Paso, Texas, maker of hair care products and equipment, also installed a white roof at its 408,000-square-foot distribution center, and was so pleased with the results that, a few years later, it went white again to top off its elegant 135,000-square-foot corporate headquarters.

  •AT&T’s El Paso facility has successfully deployed cool roofing as a means to curb air conditioning costs in the intemperate Texas heat.

  •A Florida strip mall, after measuring the energy usage of eight shops with metal-covered roofs, applied a white Stevens EP membrane to the roofs of two shops, whose energy loads declined by 25 percent the following summer.

  In recent decades, many maquilas across Mexico have come to understand the benefits of cool roof solutions as well, installing white roofing membranes to reflect Mexico’s notoriously strong sun and mitigate its intolerable year-round heat.  Tyco International in Matamoros, 3M in Juárez, Kodak in Guadalajara, and Johnson Controls and Inversys, both in Reynosa, are a few of the highly regarded global corporations that have turned to Stevens Roofing for assistance in their ongoing efforts to conserve energy and contain costs in their Mexican operations.

  Increasingly, the white roof is becoming an accepted choice in markets outside the Americas, too.  Light-colored EP membranes are being installed in new construction, renovations and re-roofings, imparting energy savings and other benefits to applications across Europe and Asia.  Most recently, 250,000 square feet of light-colored Stevens EP membrane was applied at Suwon Stadium, Suwon City, Korea, a facility built expressly for the 2002 World Cup soccer tournament that will be staged jointly by Korea and Japan.  Suwon cited the recyclability and energy-efficiency of Stevens EP as the primary reasons for its choice. 

  Given their enthusiastic reception and rate of adoption overseas, white roofing alternatives seem likely in the years ahead to enjoy a boom in Central and South America.  As Stevens’ growing base of Mexican customers will attest, maquilas are among the operations that could gain the most from the energy- and environment-saving advantages they would derive from a cool roof system. 

  Because of their ability to curb power usage and the costs related to cooling a building, white roof systems are among the rare structural improvements that pay dividends.  And with energy rates escalating at an alarming pace, a white roof could deliver significant payback in a very short period of time, making it an increasingly very attractive investment.  For maquilas and Mexican industrial businesses of every description, there has never been a better time to explore the advantages of white, environmentally sound roofing options.

  Tom Gallivan is marketing manager for Stevens Roofing Systems, a company long devoted to environmentally sound roofing solutions.  The company is headquartered at Nine Sullivan Road, Holyoke, Massachusetts 01040, and is located on the World Wide Web at   www.st evensroofing.com.