EPS Foam Insulation Properties
The Canadian CAN/ULC-S701 "Standard for Thermal Insulation, Polystyrene, Boards and Pipe Covering" provides material properties of various EPS Types:
| Thermal Resistance* RSI / 25mm thickness Minimum @ 24°C | C518 | m²•°C/ (W•25mm) | 0.65 | 0.70 | 0.74 |
| Thermal Resistance* R-Value / inch thickness Minimum @ 75°F | C518 | ft²•hr•°F/ (BTU•in) | 3.75 | 4.04 | 4.27 |
| Water Vapor Permeance* Maximum at 25mm [1inch] thickness | E96 | ng/(Pa•s•m²) | 300 | 200 | 130 |
| perms | 5.2 | 3.2 | 2.3 | ||
| Dimensional Stability | D2126 7 Days @ 70±2°C |
% linear change max. | 1.5 | 1.5 | 1.5 |
| Flexural Strength Minimum |
C203 Proc.B | kPa | 170 | 240 | 300 |
| psi | 25 | 35 | 44 | ||
| Water Absorption Maximum | D2842 | % by volume | 6.0 | 4.0 | 2.0 |
| Compressive Strength Minimum @ 10% Deformation |
D1621 Proc.A | kPa | 70 | 110 | 140 |
| psi | 10 | 16 | 20 | ||
| Limiting Oxygen Index Minimum | D2863 | % | 24 | 24 | 24 |
* Values are for 25mm [1 inch] thick samples with natural skins intact. Better values will result for thicker materials. ** The test methods used to determine the above material properties provide a means of comparing different cellular plastic thermal insulations. They are intended for use in specifications, product evaluations and quality control, but they are not intended to predict end-use product performance.
Expanded Polystyrene (EPS) is a closed cell, rigid foam plastic insulation product that uses Air as main component and does not contain the blowing agent gases HCFC or HFC, which provide a temporary increase in thermal resistance of some other insulation materials. Closed cell EPS insulation resists moisture while allowing good drying capacity, providing Long-Term Thermal Resistance (LTTR) over the long service periods of buildings. Continuous insulation eliminates thermal bridging, increasing the total effective RSI/R-value.
¾ Hour Fire Rating per CAN/ULC S101, ASTM E119 for Composite Wall Assembly with EPS c.i.
Additional Properties for all EPS Types
Maximum Service Temperature:
Long Term Exposure 75°C [167°F], Intermittent Exposure 80°C [176°F]
Solubility: Insoluble in water and generally chemically inert.
EPS dissolves in hydrocarbons, esters, aldehydes and amines.
Capillarity: None
Coefficient of Thermal Expansion: 5-7 •10-5/°K
Buoyancy-Floatation: Minimum 900 kg/m³ [50 lbs/ft³]
UV-Light Surface Degradation: EPS can be exposed to direct sunlight for a few weeks. Prolonged exposure to ultraviolet light
creates a yellow dust on the surface of EPS products, which has negligible impact on the products' properties, but may require removal before adhering other materials such as stucco or self-adhesive membranes.
GHS Classification: Non-hazardous as per GHS and WHMIS
FLAMMABILITY WARNING: Expanded polystyrene (EPS) materials sold for construction use have a fire retardant modifier but, like all organic materials, EPS Products are combustible and must not be exposed to excessive heat, sparks, open flames, or any other sources of ignition. If burned or heated above decomposition temperature, EPS can emit an irritating black smoke and acid gases. Prevent inhalation of smoke or fumes from burning or fabrication activities. In addition, when EPS insulation board is installed in the interior of a building, it must be protected by a proper thermal barrier and the installer must review applicable local, provincial and federal building codes to determine the correct thermal barrier for the particular application.
