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Northwest Foam Products, Inc. EPS Specs

Physical Properties of Expanded Polystyrene (EPS)

Federal Specifications: ASTM C 578-92

Minimum and maximum allowable values.

Property Units ASTM Test Type I Type VIII Type II Type IX
Density, Nominal pcf C303 or D1622 1.00# 1.25# 1.50# 2.00#
Density, Minimum pcf C303 or D1622 0.90 1.15 1.35 1.80
Density, Range pcf C303 or D1622 0.90-1.14 1.15-1.34 1.35-1.79 1.80-2.20
Thermal Conductivity K Factor @ 25° F BTU/(hr) (sq.ft.)(F/in) C177 or C518 0.23 0.22 0.21 0.20
Thermal Conductivity K Factor @ 40° F BTU/(hr) (sq.ft.)(F/in) C177 or C518 0.24 0.235 0.22 0.21
Thermal Conductivity K Factor @ 75° F BTU/(hr) (sq.ft.)(F/in) C177 or C518 0.26 0.255 0.24 0.23
Thermal Resistance R-value* @ 25° F at 1 inch thickness - 4.35 4.54 4.76 5.00
Thermal Resistance R-value* @ 40° F at 1 inch thickness - 4.17 4.25 4.55 4.76
Thermal Resistance R-value* @ 75° F at 1 inch thickness - 3.85 3.92 4.17 4.35
Compressive 10% Deformation psi D1621 10-14 13-18 15-21 25-33
Flexural Strength psi C203 25-30 30-38 40-50 50-75
Tensile Strength psi D1623 16-20 17-21 18-22 23-27
Shear Strength psi - 18-22 23-25 26-32 33-37
Shear Modulus psi - 280-320 370-410 460-500 600-640
Modulus of Elasticity psi - 180-220 250-310 320-360 460-500
Water Absorption % C272 < 4.0% < 3.0% < 3.0% < 2.0%
Water Vapor Transmission Perm. In E96 2.0-5.0 1.5-3.5 1.0-3.5 0.6-2.0

*R-value means the resistance to heat flow. The higher the R-value, the greater the resistance to heat flow. Typical tested R-values are based on the data provided by Nova Chemical Co., BASF Corp., and Huntsman Chemical Company.

Additional Information on All Types

  • Maximum Service Temperature: Long Term Exposure 167 degrees Fahrenheit, Intermittent Exposure 180 degrees Fahrenheit
  • Oxygen Index: ASTM test D2863 = 24.0%
  • Coefficient of Thermal Expansion: ASTM Test D 696 = 0.000035in./(in.)(F)
  • Buoyancy-Flotation: Minimum 50lbs / Cubic Foot
  • Capillarity – None
  • Long Term Exposure 167° F, Intermittent Exposure 180° F
  • ASTM Test D 2863 = 24.0%
  • ASTM Test D 696 = 0.000035in./(in.)(F)
  • Minimum 50lbs / Cubic Foot

Building Code Classification

ICC ESR-1349

U.L. File #R12290 Control #85TO Classification BRYX

Building Code Classification

Flammability Warning

Expanded Polystyrene (EPS) materials sold for construction use have a fire retardant modifier, but are considered combustible, as are all organic materials. They must not be stored or installed near open flame or any other source of ignition. In addition, when EPS insulation board is installed in the interior of a structure, it must be protected by a proper thermal barrier, and the installer must review applicable local, state, and federal building codes to determine the correct thermal barrier for the particular application.

Adjoining Materials Warning

Expanded Polystyrene (EPS) is subject to attack by liquid solvent or some solvent base adhesives and other liquid products such as gas, diesel, etc. Care should also be taken to separate any coal tar pitch products or coal tar pitch vapors from any direct contact with EPS foam.

We Cover the Following States:

  • Utah
  • Oregon
  • Washington
  • Idaho
  • Montana
  • Wyoming
  • Colorado
  • Nevada
Northwest Foam Products, Inc. |
2390 Rostron Circle | Twin Falls, ID 83301
| 208-734-7426 | info@northwestfoam.com