The US Is 'Painting' Its Streets White
14 June 2018
In a bid to fight climate change, the US is covering its streets in a grayish-white coating known as CoolSeal.
CoolSeal, made by a company called GuardTop, is a high-performance, water-based, asphalt emulsion sealcoat designed to achieve lower surface temperatures through its lighter color and reflectivity. It's sprayed onto the roadway with trucks, then spread across the surface with squeegees.
Part of the plan, is to paint over many of the city’s black roads with a reflective white coating called CoolSeal originally designed by the military to keep spy planes cool and hide them from satellite infrared cameras.
It works just like any other conventional sealcoat, it protects and maintains the quality and longevity of the surface but while most cool pavements on the market are polymer based, CoolSeal is a water-based, asphalt emulsion.
Conventional sealcoats and dark asphalt surfaces absorb heat and energy produced by the sun, which results in higher surface temperatures that can reach in excess of 160 degrees Fahrenheit. Dark-colored asphalt absorbs between 80 and 95 percent of the sun's rays, heating up not just the streets themselves but the entire surrounding area. When temperatures in cities rise above 100 degrees Fahrenheit, surface temperatures on asphalted streets can climb to 150.
The sire of temperatures on streets and areas are called by a phenomenon known as the "urban heat island effect," which can add up to 22 degrees Fahrenheit to the average air temperature in a city, compared to the surrounding area.
CoolSeal helps to reflect solar rays off asphalt so that less heat is actually absorbed, giving a 10 to 15 degrees cooler enviroment on average than the streets and areas that have not.
Additional Benefits of CoolSeal
- Energy savings and emission reductions
- Improved water 1 and air quality
- Meets LEED and EPA requirements of 33% reflectivity
- Improved comfort and safety for people and animals on playgrounds, walking paths, parking lots, neighborhoods, bike trails and other community areas
- Environmentally friendly and contains recycled materials
- Has been shown to meet skid safety requirements
- Used on public roads
- Asphalt based
- Dries to a light grey matte finish and does not cause glare
- Increased nighttime visibility for drivers, pedestrians and bikers
- Reduced street lighting costs
- Normal street cleaning is recommended to best maintain reflectance
"Heat islands occur on the surface and in the atmosphere," according to the Environmental Protection Agency. "On a hot, sunny summer day, the sun can heat dry, exposed urban surfaces, such as roofs and pavement, to temperatures 50–90°F hotter than the air1, while shaded or moist surfaces—often in more rural surroundings—remain close to air temperatures."
Los Angeles Mayor Eric Garcetti, who may make a run for president in 2020, has used the project as part of an overall plan to reduce greenhouse gas emissions in the city by 45 percent below 1990 levels by 2025.
"Climate change is a fact of life that people in Los Angeles and cities around the world live with every day. It is a grave threat to our health, our environment, and our economy — and it is not debatable or negotiable," he said in a statement last year after President Trump said he would walk away from the Paris Climate Agreement.
The innovative sealcoat is admittedly very pricey, with L.A. reportedly footing a $40,000 bill for every mile it "paints." But advocates say its benefits may just be priceless.
|Written by: Charlie Fischer|