Flashings

Controversial cool roof study is released

Researchers at Stanford University, Stanford, Calif., have authored a new study, "Effects of Urban Surfaces and White Roofs on Global and Regional Climate," which models climate response from 2005-25. The researchers say the urban heat-island effect is relatively minor in terms of any effect on global warming as a whole and light-colored, solar-reflective cool roofs may not help rein in climate change.

Mark Z. Jacobson, a professor of civil and environmental engineering at Stanford University, led the study and was assisted by Stanford University graduate student John Ten Hoeve. Jacobson says greenhouse gases and black carbon are the biggest contributors to climate change and, together, account for more than 95 percent of gross global warming since the Industrial Revolution. Jacobson also says that white solar-reflective roofs might add to, rather than lessen, global warming.

Stanford University News' announcement of the study says Jacobson's computer modeling concluded white roofs do cool urban surfaces. However, they cause a net global warming largely because they reduce cloudiness by increasing the stability of the air, thereby reducing the vertical transport of moisture and energy to clouds.

In Jacobson's modeling, the reduction in cloudiness allowed more sunlight to reach the surface. The increased sunlight reflected back into the atmosphere by white roofs increased absorption of light by dark pollutants, such as black carbon, which further increased heating of the atmosphere.

Jacobson's study is the first to focus on the effects urban heat islands have on global sea-surface temperature, sea ice, atmospheric stability, aerosol and gas concentrations, clouds and precipitation. He characterizes urban surfaces around the world at a resolution of 1 km.

Jacobson's assertion about white roofs' lack of effect on climate change has been questioned by Hashem Akbari, a former member of the Heat Island Group at Lawrence Berkeley National Laboratory, Berkeley, Calif., and current faculty member at Concordia University, Montreal.

Akbari says Concordia University's recent global simulation models estimate a global cooling effect twice its previous estimates as a result of cool roofs and cool pavements. Akbari also says other benefits of cool roofs are well-documented and beyond dispute and include a reduced energy demand for air conditioning and a reduced urban heat-island effect.

Ronnen Levinson, the Heat Island Group at Lawrence Berkeley National Laboratory's deputy leader, says the group is in the process of formulating a response to Jacobson's study.

Stanford University says the study does not suggest white solar-reflective roofs are counterproductive or misguided. Rather, it offers a rebuttal to those who doubt global warming.

The study is available online at www.stanford.edu/group/efmh/jacobson/Articles/Others/HeatIsland+WhiteRfs0911.pdf.

Asphalt demand expected to increase

The Freedonia Group Inc., a Cleveland-based industry market research firm, published Asphalt to 2015, which contains results from its November 2011 study. The study reports U.S. demand for asphalt is forecast to increase 7.4 percent annually to nearly 35 million tons—the equivalent to 191 million barrels of primary asphalt—in 2015. The expected growth represents a rebound from 2005-10 when consumption declined because of the recession and a collapse in building construction. Gains will be moderated by slower than average growth in residential and nonresidential improvement and repair applications.

Demand for asphalt in roofing and other applications is forecast to increase 5.6 percent annually to 6.3 million tons in 2015. Growth will reflect a recovery in construction of single-family housing, which will benefit asphalt roofing used in steep-slope applications, primarily asphalt shingles. Demand also will benefit from the growing consumption of modified asphaltic membranes in low-slope roofing applications. Gains also reflect a recovery in nonresidential building activity.

Asphalt to 2015 is $5,100 and available for purchase from The Freedonia Group's website, www.freedoniagroup.com.

Capital Safety issues recall

Capital Safety Inc., Red Wing, Minn., has recalled its Y-shaped Protecta® brand shock-absorbing lanyards. Capital Safety is aware of a reported, inadvertent disconnection during use of the product's locking snaphook. The affected products are Pro™ Stretch 100% Tie-off Shock Absorbing Lanyards, Nos. 1340141 and 1340161, and Pro-Stop 100% Tie-off Shock Absorbing Lanyards, Nos. 1340240 and 1340250.

The recall includes all affected lanyards manufactured between July 2010 and Oct. 31, 2011. Manufacture date is marked on each lanyard's product label.

For more information, contact Donna Sahlberg, Capital Safety's quality manager, at (800) 387-7484, ext. 5264 or Frank Courtemanche, Capital Safety's vice president of quality, at (800) 387-7484, ext. 5224.

OSHA provides Cold Stress Card

With the onset of cold weather, the Occupational Safety and Health Administration (OSHA) is reminding employers and employees to take necessary precautions to prevent and treat cold-related health problems. Workers in construction, commercial fishing, maritime and agriculture are among those who need to take precautions.

Prolonged exposure to freezing or cold temperatures may cause frostbite and hypothermia. In extreme cases, including cold water immersion, exposure can lead to death. Danger signs include uncontrolled shivering, slurred speech, clumsy movements, fatigue and confused behavior.

OSHA's Cold Stress Card provides a reference guide and recommendations to prevent hypothermia and frostbite. Tips include:

• Recognize the environmental and workplace conditions that may be dangerous.
• Train workers about cold-induced illnesses and injuries.
• Be sure workers in extreme conditions take frequent, short breaks in warm, dry shelters to allow their bodies to warm up.
• Encourage workers to wear proper clothing for cold, wet and windy conditions, including layers that can be adjusted to changing conditions.
• Try to schedule work for the warmest part of the day.
• Eat warm, high-calorie foods, such as hot pasta dishes.
• Drink warm, sweet beverages, such as sugar water and sports drinks, and avoid alcohol and drinks with caffeine, such as coffee, tea, soda or hot chocolate.

OSHA releases educational videos

The Occupational Safety and Health Administration (OSHA) has released 12 educational videos about potential hazards in the construction industry.

The videos are based on real-life incidents and include detailed depictions of injuries and fatalities and the safety measures that would have prevented them.

Written for workers and employers, including workers with limited English-language proficiency, the videos discuss falls in construction, workers who are struck by vehicles and heavy equipment, sprain and strain injuries, trenching and excavation hazards, and carbon monoxide poisoning.

Most of the videos are two to four minutes, and each one is available in English and Spanish. The English videos are available at www.osha.gov/dts/vtools/construction.html, and the Spanish videos are available at www.osha.gov/dts/vtools/construction_sp.html.