Insulation Technology, Inc.
35 First Street
P.O. Box 578
Bridgewater, MA 02324
Tel: (508) 697-6926
Fax: (508) 697-6934
Physical Properties of EPS Insulation
Long Term Insulation
R-value means the resistance to heat flow. The higher the R-value,
the greater the resistance to heat flow. EPS insulation (0.90 pcf) provides a
typical R-value of 3.60 per inch at a mean temperature of 75 degrees F and a
typical R-value of 4.00 per inch at a mean temperature of 40° degrees F.
When properly installed and protected from moisture, the R-value of EPS
insulation remains constant. This is because the closed cell structure of EPS
contains only air. The R-value of EPS will not decrease with age. As a result,
the thermal resistance or R-value, of EPS may be used without any adjustment
Water vapor transmission through insulation materials is the
passage of water through the material in the vapor phase. In comparison to
other common building materials, EPS insulation has moderate water vapor
permeability per unit of thickness. Recommended design practices for walls and
foundations should be followed in the selection of vapor and moisture barriers
for severe exposures.
A study by the Energy Materials Testing Lab (EMTL)
has shown that EPS insu-lation installed in well-constructed roofs does not
absorb appreciable moisture, even under conditions characteristic of prolonged,
cold, damp winters. The small amount of moisture has little or no effect on the
compressive or flexural strength, and the EPS insulation retains between 95%
and 97% of its thermal efficiency.
Each roof application should be
studied to determine the need for a vapor retarder to control internal
condensation. Based on NRCA/MRCA-sponsored studies, vapor retarder placement
for EPS insulated roof systems is less critical than for other types of roof
EPS is able to withstand the rigors of temperature cycling,
assuring long-term performance. In a series of tests conducted by the Dynatech
Research and Development Co., Cambridge, MA, core specimens removed from
existing freezer walls, some as old as 16 years, demonstrate EPS withstands
freeze-thaw cycling without loss of structural integrity or other physical
For foundation and wall applications in which EPS bears
a minimal load, ASTM C578 Type I EPS material is adequate. The resilience of
EPS insulation board provides reasonable absorption of building movement
without transferring stress to the outer skins at the joints. In most roofing
applications, Type 1 EPS insulation material provides the dimensional stability
and compressive strength necessary to withstand normal roof traffic and
equipment weight. If greater rigidity and strength are needed, as a result of
design loads, higher density EPS insulation products are available. Please
contact Insulation Technology for recommendations regarding your
many construction materials, EPS is combustible. EPS products are manufactured
with a flame retardant; however, EPS insulation will burn upon exposure to
flame or heat sources, including, but not limited to, open flames, welder's
torches, or other sources of heat. EPS insulation should be covered with a
thermal barrier or otherwise installed in accordance with applicable building
code requirements. It is the responsibility of the purchaser to ensure that EPS
insulation is properly handled and stored on the jobsite.
subject to attack by some petroleum-based solvents. Care should be taken to
prevent contact between EPS and these solvents and their
In roof construction requiring hot asphalt, temperatures
should not exceed 250 degrees F at the time of direct contact with EPS
insulation. Avoid contact between EPS and high-temperature equipment, such as
asphalt kettles and flame sealers.
Prolonged exposure to sunlight will cause slight discoloration
and surface dusting of EPS insulation. The insulating properties will not be
significantly affected under normal usage. EPS stored outside should be
protected with a light-colored opaque material.
EPS insulation may be manufactured to meet or exceed the
requirements of ASTM C578 and applicable building codes.
For more information about
Insulation Technology Inc.'s products, please contact us online or give us a call at 508
We look forward to hearing from you soon and welcome the
opportunity to quote your next project.