By Anthony R. Wood
Inquirer Staff Writer
Right after last month's premature heat wave, three men in polyethylene jumpsuits were atop Mary Owens' Southwest Philadelphia rowhouse, slathering her roof with a thick, white acrylic coating.
The gunk - part water, part polymer, part calcium carbonate (essence of Tums) - should lower the temperature indoors, greatly improving the odds that the 74-year-old woman will survive even the most searing days of this summer.
In the 1990s, more than 250 Philadelphians, most elderly, died of heat-related causes. The majority of victims were found in top-floor bedrooms, leading experts to suspect that a cityhallmark - the flat blacktop roof - had played a lethal role.
Black soaks up the sun's energy; white repels it. Proceeding on that simple principle, a Center City nonprofit, Energy Coordinating Agency Inc., began two years ago coating roofs of older residents in low-income neighborhoods in South and Southwest Philadelphia.
With 200 finished, the first analysis is in: The coatings are doing their job.
On the hottest days - mid- and upper 90s in August last year - rooms directly under the white roofs were about 3 degrees cooler than those beneath black roofs, according to a study by the Boston energy-consulting firm Martin Blasnik Associates. Given a body temperature of 98.6, a drop in room temperature from 95.6 to 92.6 actually doubles the degree difference between the room and the body.
That, health officials say, can be the difference between life and death.
A blacktop roof might rocket to 170 degrees on a 95-degree afternoon, and still be at 150 after dark. On the same day, a roof covered with the hard, white membrane would not exceed 120 degrees, and would cool to near air temperature with sundown. That has an impact not only inside the house - but, as researchers found, throughout the entire neighborhood.
On the 6200 block of Catharine Street, where all 30 roofs were coated late last summer, the average air temperature fell about one degree compared with nearby black-roofed blocks.
"Even when it got moderately hot, people were telling us that they noticed a difference at ground level," program manager Neal Resnick said.
Lorraine Lumpkin, the block captain who rallied her neighbors to participate, said the change, even on the first floor of her home, had been "huge.
About 80 percent of Philadelphia's rowhouses have flat or slightly pitched black roofs. They are ubiquitous, as well, in the region's smaller cities, including Camden, Chester and Norristown. But it is in these "urban heat islands" that they are also the most dangerous.
With buildings blocking breezes and endless pavements absorbing heat, these cities can be 2 to 10 degrees warmer in summer than surrounding towns.
Paradoxically, in leafy suburban neighborhoods where heat rarely is a hazard, many houses have lighter-colored, angled roofs.
"The housing stock in Philadelphia was made for cold weather, not hot," said Lawrence Robinson, deputy Philadelphia medical examiner.
A study has shown that heating costs in white-roofed houses are about 3 percent higher, but that cooling costs are 22 percent lower - making them particularly attractive for commercial buildings, especially in energy-conscious California.
Only in Philadelphia, though, is there a residential program whose main mission is to save lives, according to the U.S. Environmental Protection Agency.
The location is no coincidence.
Before 1993, heat-wave death tolls were limited to victims who died of hyperthermia, with core body temperatures of at least 105. But that summer, the Philadelphia Medical Examiner's Office made a controversial decision to include all fatalities in which heat appeared to play a role. The resulting tally was 118 victims, a city record.
After an investigation, the Centers for Disease Control and Prevention determined that the Philadelphia accounting method was valid, in effect making extreme heat the nation's No. 1 weather killer.
In 1995, Chicago used the same reporting methods and counted more than 700 heat-related deaths.
Roofing has become a major issue in Chicago, which next month will amend its building code to require lighter-colored roofs on new construction.
Washington and Boston are looking at Philadelphia's pilot program, Resnick said.
Unlike black asphalt, the white coatings are not cheap - about $1,200 per roof - but they can extend roof life by 10 years. The Philadelphia program has used foundation grants and U.S. Department of Health and Human Services funds to work on the 200 houses, with enough money left to do about 300 more.
In 1993, Mary Owens lost a neighbor to the brutal heat beating on the rowhouses of South 51st Street. The only good thing she has to say about that summer is that it didn't kill her, too.
Her downstairs windows were sealed shut, and still are.
So last month, when temperatures soared into the 90s, she was "a wreck," she said. "I mean, hey, this is just April. How we going to make it if this keeps up?"
The answer could be just above her head.
Posted on Sun, May. 05, 2002, in Philadelphia Inquirer
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