Expanded Polystyrene General Information

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Types of Expanded Polystyrene

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Expanded Polystyrene R-VALUE

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General Information about Expanded Polystyrene

EPS (Expanded Polystyrene) is a CLOSED cell material.

EPS is made up of Hydrogen and Carbon atoms with the addition of a blowing agent (Pentane) used only in the manufacturing process. The blowing agent dissipates as the material cures.

R-Values and Compressive strengths increase with density.

Tests have shown that when burned, EPS is no more toxic than wood or paper burning. The by-product of burning EPS is Carbon Monoxide.

Maximum Temp exposure to EPS should not be higher than 167 degrees F for extended periods, nor higher than 184 degrees F at any time.

EPS will not support bacterial or fungus growth. EPS has no food value.

Flame Spread & Smoke Developed Ratings vary slightly depending on Raw Material manufacturer.

***** As a general rule, Flame spread is 15 and Smoke Developed is 150 to 250.

Care and Handling

Expanded Polystyrene (EPS) products are produced and distributed by Hendren Plastics, Inc. in a variety of shapes and sizes for numerous uses. These include Packaging, Insulation and Flotation.


Precautions for Use

Cutting & Shaping

Fire Precautions

First Aid Treatment

Advice & Assistance


Density Chart          
Nominal pcf  1 #   1.25 #   1.5 #   2 #
Actual pcf  0.9  1.15  1.35  1.8


R Value 25 F per inch 4.2 4.4 4.6 4.8 R Values indicate the resistance to the transfer of heat.
  75F   3.6 3.8 4 4.2 The higher the R Value, the higher the resistance.
K Factor 40F BTU/(hr) 0.24 0.235 0.22 0.21 K Factors are not used or asked for very often. They deal with
  75F (sqft)(F/in) 0.26 0.255 0.24 0.23 the Thermal Conductivity of insulation.
Compressive   psi 10 13 15 25 Multiply the #'s by 144 to find pounds per sq foot
Strength @ 10% deform.             These weights will compress the material approx 10%
Flexural   psi 25 30 40 50 Multiply the #'s by 144 to find pounds per sq foot
Water Vapor   max perm 5 3.5 3.5 2 Shows air moisture transfer through EPS
Permeability   per inch          
Water   % by Vol 4 3 3 2 Maximum amount of water absorbed in % of volume
Bouyancy   lb/cuft 60 60 60 60 lbs/cuft to push EPS just below water surface.
              Allow at least 50% safety factor


 Other data also available on request:
   Tensile Strength   Dimensional Stability
   Shear Strength     Bond Strength
   Shear Modulus     Sound Absorption
   Modulus of Elasticity     Coeffecient of Thermal Expansion
   Capillarity     Oxygen Index