FAQ Series: What Is Your Airpop® (EPS) Material Compressive Strength?

Frequently asked questions. As an industry leader, we feel it is important to share our expertise as well as continue to educate and inform others of Plymouth Foam’s materials and capabilities.

Compressive strength is a crucial component of Airpop® (EPS) for insulation and building materials. The most important mechanical property of Airpop® (EPS) is the resistance to compressive stresses, which increase as the density becomes higher. The compressive resistance is between 10 – 60 psi for most construction applications.

Our Plymouth Foam product can be produced to meet your specific strength requirements per project needs.

Airpop® EPS compression properties
ASTM C578 Specifications
Property ASTM Test Units Type XI Type I Type VIII Type II Type IX Type XIV Type XV
Compressive Resistance (2″Cube)
at 10% Strain Deformation D1621, C167 Min psi (kPa) 5   (35) 10 (69) 13    (90) 15 (104) 25 (173) 40  (276) 60 (414)
Airpop® Geofoam compression properties
ASTM D6817 Specifications
ASTM D6817 Specifications EPS 12 EPS 15 EPS  19 EPS 22 EPS 29 EPS  39 EPS 46 EPS 48
Property ASTM Test Units
Compressive Resistance (2″Cube)
at 1% Strain Deformation D1621, C165 Min psi (kPa) 2.2 (15) 3.6 (25) 5.8   (40) 7.3 (50) 10.9 (75) 15  (103) 18.6 (128) 22.2 (153)
at 5% Strain Deformation D1621, C166 Min psi (kPa) 5.1 (35) 8.0 (55) 13.1 (90) 16.7 (115) 24.7 (170) 35  (241) 43.5 (300) 52.2 (360)
at 10% Strain Deformation D1621, C167 Min psi (kPa) 5.8 (40) 10.2 (70) 16  (110) 19.6 (135) 29 (200) 40  (276) 50 (345) 60 (414)

Standard Specification Test Methods for Airpop® (EPS) are as follows:

  • ASTM C578, Standard Specification for Rigid, Cellular Polystyrene Thermal Insulation: types, physical properties, and dimensions of cellular polystyrene used as thermal insulation for temperatures from -65 to 165°F. ASTM C578 covers types of EPS thermal insulation currently available and the minimum requirements for the properties considered most important.
  • ASTM C203, Test Method for Breaking Load and Flexural Properties of block-type thermal Insulation; flexural strength and compressive resistance values are included.
  • C165, Test Method for Measuring Compressive Properties of Thermal Insulations and/or
  • D1621 for Test Method for Compressive Properties of Rigid Cellular Plastics.

To meet the compressive resistance requirements specified in ASTM C578, polystyrene thermal insulation boards must provide the following compressive strengths at 10% deformation when tested in accordance with ASTM D 1621.

The EPS Industry Alliance shares Airpop® (EPS) high resiliency and strength characteristics, expanded polystyrene insulation offers:

  • Absorption of substrate and facing movement caused by temperature changes and structural deflections
  • Absorption of substrate irregularities
  • Thickness recovery following excessive construction load exposures
  • Suitable subgrade reaction for effective load distribution

In conclusion, the structural strength of Airpop® (EPS) is crucial for every project. We take pride in our work and customer satisfaction from start to finish and after.

We love it when you ask us these questions.  Please continue to ask more or reach out to our team directly: sales@plymouthfoam.com.