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[STK]
[IN] CST HMI HHP ENV
[SU] SVY
TO ARCHITECTURE, ENVIRONMENTAL, AND NATIONAL EDITORS:
XPS Insulation Tests Confirm Diminished R-value When Exposed to Water
Absorption
CROFTON, Md., April 3, 2014 /PRNewswire-USNewswire/ -- The EPS
Industry Alliance (EPS-IA) recently completed a series of tests on
extruded polystyrene (XPS) to examine the effects of moisture
absorption and R-value in different field applications. Two new
technical resources look at the behavior of rigid foam insulation
exposed to water, specifically related to the material's drying
potential and R-value retention. When evaluating XPS material samples
extracted from roofing and below grade applications, in these
long-term installations, XPS did not maintain its initial R-value.
Buildings have been and always will be exposed to moisture. It is not
a good thing or a bad thing; it is merely another component of the
building design process. When materials are exposed to moisture, the
ability to dry is key to maintaining thermal resistance. This issue is
addressed in "Drying Potential of Polystyrene Insulations Under
Extreme Environmental Cycling Conditions", which evaluates the
free-thaw cycling effects on rigid foam plastics as prescribed by ASTM
C1512. The test results indicate XPS exceeds the recommended water
absorption threshold dictated by ASTM C578 by a factor of 2.4, and,
test data rendered by Intertek Testing Services show that in-situ
water absorption from XPS samples taken from four different locations
is widely variable from 5 - 60% by volume.
Standardized laboratory testing, while not intended to replicate
in-situ, real-world conditions, substantiate expanded polystyrene
(EPS) performance claims to deliver consistent R-value in building
environments that may be exposed to moisture. XPS producers claim its
lower moisture absorption rate is a benefit; however, this is based on
flawed logic. XPS R-values begin to deteriorate at only 0.03 percent,
meaning its tolerance for water absorption is extremely low. This
phenomenon is demonstrated in the test results published in "XPS
Insulation Extracted After Field Exposure Confirms High Water
Absorption & Diminished R-value". On the other hand, EPS demonstrates
excellent drying abilities and has a much higher tolerance for
moisture exposure while still delivering the same R-value throughout
the life of the building.
Expanded polystyrene exhibits superior moisture-related performance
properties over XPS. It has higher vapor permeability, meaning it
helps promote drying in a wall system. As shown in the EPS-IA
technical bulletins, EPS is inherently more capable of tolerating
moisture absorption than XPS. Even at 3.0 - 4.0% moisture absorption,
expanded polystyrene insulation delivers consistent R-value of 3.1 -
4.3 per inch.
When evaluating rigid foam insulation performance properties,
non-standardized testing, modified test methods or testing not
intended for the materials being evaluated should be viewed with
skepticism. EPS-IA's new information comparing EPS and XPS moisture
absorption and R-value retention is based on testing conducted by a
third-party, certified testing laboratory and relies on industry
recognized standards ASTM C1512, ASTM C518 and others.
EPS-IA is confident these new documents will be a valuable resource
for architects, contractors and consumers that are seeking the best
possible insulation for their construction projects. For more
information on expanded polystyrene and the results of EPS-IA's new
test results please contact Betsy Steiner, EPS-IA Executive Director,
at emsteiner@epsindustry.org or 800-607-3772.
SOURCE EPS Industry Alliance
-0- 04/03/2014
/Web Site: http://www.epsindustry.org
CO: EPS Industry Alliance
ST: Maryland
IN: CST HMI HHP ENV
SU: SVY
PRN
-- DC97196 --
0000 04/03/2014 13:15:00 EDT http://www.prnewswire.com
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