Building Operating Management September 2011 - FacilitiesNet

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buildingoperatingmanagement
SEPTEMBER 2011
ics, reductions in the workforce and
environmental considerations. All of
these issues continue to be vital concerns
in the market. In fact, a recent
poll about roof purchasing habits
indicates that environmental issues
are now the No. 1 factor in the selection
of roof materials for consumers,
while the material’s ease of application
is the first priority in the contractor’s
selection process.
New Codes and Regulations
Before taking a look at the specific
requirements of the various codes and
voluntary rating systems, it’s important
to understand the metrics they use.
Reflectivity ratings are based on
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the roof surface’s ability to reflect ultraviolet
rays from the sun. Studies
have indicated that reflective surfaces
will cool the building in the summer,
decreasing the use of air conditioning,
which decreases cooling costs and energy
capacity. The Energy Star program
establishes the reflectivity rate of a roof
surface for low-slope (less than 2:12)
roof systems at .65 the first three years
and .50 after three years. LEED provides
points based on this program.
Emissivity measures the ability of
a roof to emit back to the atmosphere
the solar energy that it has absorbed,
rather than transferring that absorbed
energy to the interior of the building.
Finally, the Solar Reflective Index (SRI)
is a relatively new measure that combines
solar reflectivity and emissivity. It
is calculated via ASTM standard E 1980.
LEED for New
Construction’s
“heat island reduction”
credit gives one point
for a reflective roof with
an SRI of at least 78
The past decade has seen a concentrated
effort to develop standards
for environmental and sustainable
materials. So far, these standards have
not been added to the International
Building Code (IBC). However, some of
these regulations have become codes
in select municipalities and states. For
instance, in California, Title 24, the
state’s energy code, has been part of
the state building code for a number of
years. Several municipalities throughout
the country have incorporated
Energy Star roof reflectivity ratings into
their codes. And most industry experts
agree that it is just a matter of time before
LEED becomes part of the IBC.
In fact, the new International Green
Construction Code, due out in 2012,
will include standards for cool roofing.
LEED is a green building rating system
based on points through energy
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