green builders are ASTM standards
such as E2766 on the installation of
roof-mounted photovoltaic arrays.
E2766 details the requirements for the
installation of solar arrays on steep-
sloped roofs, including proper water-
shedding integration with the roof
system and flashing of roof penetra-
tions.
To help measure the solar reflectance
of their products, manufacturers of
glass, coatings, films and optical
Another important green construction
their specific building requirements.
components of solar energy systems
area that D08 is addressing is "cool"
Solar Energy: Powering Green
rely on ASTM standard E903 on solar
roofs, a green roofing approach that
absorptance, reflectance and trans-
Building
responds to the sun's solar energy by
mittance of materials. This test
In the last several years, buildings with
reflecting its heat and emitting its radi-
method helps manufacturers assess
rooftop solar arrays have become
ation back into the atmosphere. A vari-
the reliability, durability and perfor-
increasingly
commonplace.
ety of cool roof materials, including
mance of these components in order
According to the global consultancy
asphalt shingles, metal, reflective coat-
to optimize the entire materials system
McKinsey & Company, technological
ings, roofing membranes and roofing
performance.
leaps and the scaled-up production of
tiles, helps mitigate the sun's effect.
solar panels have made solar power
Impacting Green Building Materials
When less heat is absorbed into a
dramatically less expensive. What
A green home is much more than the
building's interior, occupants benefit
started as a technology used to power
sum of its parts -- it also reflects its
from lower air-conditioning energy use
satellites, telescopes and other vehi-
impact on the environment for as long
and a more controllable and constant
cles in outer space is now used in
as it stands. Green builders are
indoor environment.
homes, office buildings and ware-
compelled to pay closer attention to all
Cool roof techniques can be used in
houses, and even in the form of solar
the details that come into play during a
low-slope roofs, which have relatively
farms covering acres of land.
building's entire life cycle -- including
flat rooflines and are installed atop
For home and commercial facility
where it is built, how many resources it
institutional, commercial, industrial,
owners, solar offers a clean energy
consumes, how it affects the environ-
office, retail and multifamily buildings;
source that leads to lower utility bills,
ment and what materials go into its
and steep-slope roofs, which have an
independence from the traditional
construction. Negative environmental
inclined roofline and are generally
power grid and a reduced carbon foot-
impacts can be minimized through
used on single family homes. Two
print. The growing demand is driving
responsible and intentional use and
standards
developed
by
green builders to incorporate the
application of green materials.
Subcommittee
D08.18
on
installation of solar arrays in their
Products that contain a high percent-
Nonbituminous
Organic
Roof
design and construction projects.
age of rapidly renewable resources
Coverings play a valuable role in
Supporting their efforts are numerous
have a lighter environmental footprint
assisting stakeholders in the imple-
test methods, practices and guides
and are strongly encouraged in the
mentation of cool roof systems. ASTM
developed by ASTM International
LEED rating system. Material durabil-
standards E1918 on solar reflectance
Committee E44 on Solar, Geothermal
ity is also an important consideration
and E1980 for calculating solar
and Other Alternative Energy
in green buildings as using durable
reflectance index help building
Sources. E44 has a growing set of
materials reduces life cycle costs and
designers and consumers in choosing
standards touching on a wide range of
limits environmental impacts.
the cool roof materials most suitable to
clean energy applications. Assisting
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Issue 72 March 2014
2014
72

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