|
Meeting Energy Star® Solar-Reflective
Roofing Requirements
These days we are trying to be
more energy conscious. One of the best changes we can make
to lower energy consumption is to change our roofing
material to a coated metal roof that will reflect the sun’s
rays, lowering the amount of energy that you use to cool
your home.
As you know, Colourcoil
Industries is now a U.S
Energy Star Partner (see previous
newsletter). In order to qualify, our high performance
pre-painted steel used for the downstream manufacturing of
"Cool Metal Roofs" must conform to the required
specifications as laid out by U.S EPA (Environmental
Protection Agency) and DOE (Department of Energy).
Key Product Criteria
|
Equipment |
Specification |
|
Roofing |
- Low Slope roofs must have an
initial solar reflectance of >= 0.65. After 3
years, the solar reflectance must be >= 0.50.
- Steep Slope roofs must have
an initial solar reflectance of >= 0.25. After 3
years, the solar reflectance must be >= 0.15.
|
Roof Surface:
The uppermost part of the roof system that is in direct
contact with solar radiation.
Low-Slope Roofs:
Surfaces with a slope of 2:12 inches or less. (As defined in
ASTM Standard E 1918-97).
Steep-Slope Roofs:
Surfaces with a slope greater than 2:12 inches.
Solar Reflectance:
Solar reflectance (SR) is the ability of a material to
reflect solar energy from its surface back into the
atmosphere. The SR value is a number from 0 to 1.0. A value
of 0 indicates that the material absorbs all solar energy
and a value of 1.0 indicates total reflectance.
Some Comments:
(1) Take note that in order to qualify for Energy Star, there are two Solar Reflectance
(SR) values;
one at the time of installation and one 3 years after
installation. This means that home owners
will get the most benefit from a metal roof whose
solar-reflective colours last the longest. Once
the colour on the roof has faded, the
solar-reflective properties are lost.
(2) The solar reflectance
(SR) values mentioned above differ from the requirements of
Malaysia's
Green Building Index (GBI) or LEEDS (Leadership
in Energy and Environmental Design). GBI
or LEEDS require a value call SRI (Solar
reflective index). SRI allows actual measured solar
reflectance and thermal emittance values to be
combined into a single value by determining
how hot a surface would get relative to standard
black and standard white surfaces. Only SRI
value at the time of installation is required.
There are no requirements for SRI values after
installation. (see previous article on radiative
properties of cool metal roofs)
(3) Products meeting
Energy Star® requirements will easily meet
GBI or LEEDS solar reflective
requirements.
(4) Where are this SR or
SRI values
published? Pre-painted or colour coated steel manufacturers
will have both values of SR & SRI published in their colour
charts.
Whether you are environmental or just like to save money, a
metal roof manufactured using COLOURCOIL®
Kool, Energy Star compliant pre-painted steel
can help you achieve both these tasks, and will help your
home stay cooler in the summer months. At the same time you
are reducing your fossil fuel consumption by using less
energy to cool your home.
[
Back to Top
]
KYNAR 500®
Resin Coatings are the Best Choice for "cool metal roofs"
COLOURCOIL PVF2 and METALLIC PVF2 Series
pre-painted steel solar reflective colour coatings are
manufactured using Kynar 500® resin. In this article we will
explain why Kynar 500® resin based coating is really the best
choice for the downstream manufacturing of "cool metal
roofs".
The proven durability of full strength 70%
Kynar 500® resin type paint systems allows for stable color
and film integrity over decades of exposure. This durability
is also seen in the retained amount of initial solar
reflectance. Thus, paint systems based on the Kynar 500®
resin have a surface that does not retain dirt, remains
cool, and retains its original color better than any other
resin type.
In the design and performance of a building, the owner wants
to know that the initial energy cost savings projections are
maintained over the life of the roof. Most other roof types
have been documented to lose some percentage of their
initial solar reflectance due to dirt pick up and overall
degradation from the weather. In those cases, the aged
performance of these cool roofs is far from what the
building experiences in the early years. The strong
performance of Kynar 500® based paint system which is
maintained over time is especially apparent in the retention
of the initial solar reflectance of cool Kynar 500 based
pre-painted paint systems. In research conducted by Oak
Ridge National Laboratory on behalf of the Cool Metal
Roofing Coalition Kynar 500® based pre-painted metal test
panels exposed in South Florida were found to retain 95% of
their original solar reflectance over more than 30 years.
Typically, dirt pick-up and retention is responsible for
many roof products' solar reflectance dropping over time.
This is also true for some conventional resins used for
pre-painted metal roofing. However, Kynar 500 based
pre-painted metal roofing readily sheds dirt and does not
promote the formation of algae or other microbial growth on
the surface which could lower the solar reflectance.
A cool Kynar 500® based pre-painted metal roof
product has the best protection against color fade, chalk
and erosion of gloss AS WELL AS having the highest solar
reflectance of a color formulated in any other paint resin
type. When selecting a durable solar-reflective pre-painted
steel material for your next roofing project, there really
are no better choices than Colourcoil Industries' flagship
products, COLOURCOIL PVF2 Series and METALLIC PVF2 Series.
Find out more about Colourcoil high
performance pre-painted steel products......
[
Back to Top
]
What is a Cool Metal Roof?
For the benefit of our new readers or those who missed
our previous articles, here is a short article on what cool metal roofs are
about.
Cool roofing is defined differently by
various performance criteria in codes, standards, and
incentive programs. In general, a cool roof is one that has
relatively high solar reflectance and high thermal emittance.
During the daylight hours, a
roof is constantly subjected to solar energy striking its
surface. The term “Solar Reflectance” is a measure of the
amount of that solar energy that is immediately reflected
from the surface. It is not reflected heat, but reflected
electromagnetic energy from the sun. Solar reflectance is
reported as a decimal (0 – 1.00) or as a percentage
(0-100%). The solar energy that is not reflected away from
the surface is absorbed into the outer surface of the roof
product and is converted into heat. The heat can be removed
by convection as air flows over the surface, or by
conduction through the roof material into the sheathing
below. The energy that is left can also be re-emitted to the
night sky in the form of infrared energy. That re-emitted
energy is referred to as thermal emittance, which is also
expressed as a decimal (0 – 1.00) or as a percentage
(0-100%).
A cool metal roof with high solar reflectance and high
thermal emittance would have a lower surface temperature as
compared to a roof with low reflectance and low emittance.
In the case of a cool metal roof, a lower surface
temperature translates into less heat gain into the attic
space or living space below the roof. The result is a cooler
living space and lower cooling/heating energy consumption.
[
Back to Top
]
COLOURCOIL WEBSITE
UPGRADED
 Colourcoil
website has just been upgraded to improve site visitor's
viewing experience with Windows Explorer 8 where visitors
can use the zoom tool located at the bottom of the webpage.
A new video clip has been added
to the website. To find out why architects
prefer Kynar 500 metal coatings,
click here to view the
video.
[
Back to Top
]
Exhibition - ARCHIDEX
2010
 Colourcoil
Industries will be participating in the upcoming
Archidex2010 which will be held at the Kuala Lumpur
Convention Center in Malaysia. We hope to see you at our
booth as you will be able to see our high performance
pre-painted steel that comes in a wide range of new and
exciting solar-reflective colours. Our dedicated team of
marketing staff will be there to answer any questions you
may have. We are located at
Booth number:
#6792 - 6794
See you there!
[
Back to Top
]
Need more info?
Whether you are an
architect, engineer, developer, house owner or a metal
roofing or wall cladding manufacturer, our marketing team
will be most delighted to discuss with you on your specific
product requirements.
If you wish to make a factory visit, obtain a free brochure
or complete specifications and colour charts, please contact
our courteous and friendly marketing staff by calling the
nearest office or just drop us an email at
info@colourcoil.com.
[
Back to Top
] |
