[Ccpg] Green Rooftop Technology
ccpg-admin at arashi.com
ccpg-admin at arashi.com
Mon May 28 09:14:00 PDT 2001
Hi everyone
Margie Bushman found this article and more links to Green Rooftops, check
it out
wes
>http://www.cnn.com/2001/NATURE/01/01/rooftop.gardens.enn/index.html
January 1, 2001
Web posted at: 12:01 p.m. EST (1701
GMT)
By Environmental News Network staff
During the summer months, the
temperature of a conventional flat
rooftop can soar up to 140 degrees
Fahrenheit - hot enough to fry an egg.
This heat creates tremendous updrafts, circulating tiny
particles that can clog
lungs. The additional heat increases the need for
electricity production, which
further adds to air pollution.
By contrast, a grass rooftop can't get any hotter than
about 77 degrees. This
innovative technology can help relieve city smog and cut
energy consumption.
With enough green roofs, the temperature of a entire
city can decrease.
A 3- to 7-degree temperature drop translates to a 10
percent reduction in air
conditioning requirements. For a one-story structure
with a green rooftop,
cooling costs can be cut by 20 percent to 30 percent.
A recent study done by Weston Design Consultants for the
city of Chicago
estimates that the greening of all of the city's
rooftops would produce
$100,000,000 in saved energy annually. Peak demand would
be cut by 720
megawatts - the equivalent energy consumption of several
coal-fired generating
stations or one small nuclear power plant.
Green rooftops offer other environmental benefits. They
capture and filter air
pollutants and retain as much as 50 percent to 70
percent of the storm water that
they capture. This reduces storm water contamination and
the risk of flooding.
Green rooftop technology replaces traditional flat
rooftops with a series of
carefully engineered layers. A water- and root-repellent
membrane is installed on
top of a reinforced roof structure. A drainage layer
separates growing material
from the underlying membrane.
A filter cloth keeps the drainage layer from getting
plugged by the growing
medium, which constitutes the top layer. This growing
medium is designed to be
as light as possible and still support plant growth.
Significant long-term savings can offset the cost of
installing a green rooftop.
Green rooftops last twice as long as standard roofs,
reducing maintenance and
replacement costs. They also muffle sound, creating a
more efficient work
environment.
Green rooftop technology is just being introduced in the
United States and
Canada, but it is a common feature of construction in
Germany, France, Austria,
Norway, Switzerland and other European countries.
In North America, cities such as Chicago and Toronto
have established green
rooftop demonstration projects on city-owned buildings.
Washington, D.C., and
Portland have begun to conduct research on the benefits
of public green
rooftops.
Copyright 2000, Environmental News Network, All
Rights Reserved
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RELATED SITES:
City of Chicago
Heat Island Group
Green Roofs for Healthy Cities
Greenroofs.com
Urban Agrigulture Notes
Rooftop Gardens Resource Group
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