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Rigid Foam Insulation Properties

Expanded Polystyrene (EPS) is a high-performance, closed cell, rigid foam insulation material containing air as main ingredient. EPS insulation resists moisture, mold, and fungi with low environmental impacts, high & stable Long-Term Thermal Resistance, and good drying potential over the long service periods of buildings. Adding continuous insulation (c.i.) offers higher effective insulation values than adding similar amounts of cavity-insulation and it greatly reduces the risk of condensation and mold on framing members with proper detailing & installation. All Korolite® types are available in various standard and customized sizes & thicknesses.

Environmental Product Declaration (EPD) certified by UL Environment

¾ Hour Fire Rating for Composite Wall Assembly with EPS c.i. CAN/ULC-S101, ASTM E119

Meets NFPA 285 with specific limitations for an exterior wall assembly with EPS c.i.

Rigid Insulation Boards
Material properties of various Korolite® Insulation Types
Property Units Korolite® Types Test Std.
100 130 160 200 250 300 400
Third-Party Certified Type Canada 1   2   3     CAN/ULC-S701
USA I   II         ASTM C578
Compressive Resistance1,4         ASTM D1621
@ 10% Deformation
Minimum
psi 10 13 16 20 25 30 40
kPa 70 90 110 140 172 210 276
Thermal Resistance1,2,3 Minimum @ 24°C [75°F] ASTM C518
R-Value/ inch thickness
ft²•hr•°F/ (BTU•in) 3.7 3.8 4.0 4.0 4.2 4.2 4.2
RSI / 25mm thickness
m²•°C/ (W•25mm) 0.65 0.67 0.70 0.70 0.74 0.74 0.74
Flexural Strength¹
Minimum
psi 25 30 35 40 50 51 60 ASTM C203
Proc.B
kPa 172 208 240 280 345 350 414
Water Vapor Permeance1,2
Maximum at 1 inch thickness
perms 5.0 3.5 3.5 3.3 2.3 2.3 2.3 ASTM E96
ng/(Pa•s•m²) 287 201 200 190 130 130 130
Water Absorption1,5
Maximum
% by
volume
4 3 3 3 2 2 2 ASTM D2842
Dimensional Stability¹ % linear
change max.
1.5 1.5 1.5 1.5 1.5 1.5 1.5 ASTM D2126
7 Days @ 70±2°C
Density¹
Minimum
kg/m³ 14.4 18.4 21.6 24b 28.8   38.4 ASTM C303
or D1622
lbs/ft³ (PCF) 0.9 1.15 1.35 1.5b 1.8   2.4
Additional Thermal Resistance Infob @25°F 4.35 4.5 4.76 4.8 5.0 5.0 5.05 ASTM C518
or C177
R-Value/ inch thickness
typical2,3,b
ft²•hr•°F/ (BTU•in) @40°F 4.17 4.3 4.55 4.6 4.76 4.76 4.85
@75°F 3.85 3.9 4.17 4.2 4.35 4.35 4.50

¹ The test methods used to determine the 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.  ² Values are for 1 inch [25.4mm] thick samples with natural skins intact. Better values will result for thicker materials.  ³ R means resistance to heat flow. The higher the R-value, the greater the insulating power.  4 The elastic limit is between 1% and 2% strain. Compressive resistances at 10% strain are provided for applications where the intended end-use includes plastic (permanent) deformation under load5 The lab-test method for water absorption uses complete submersion under a head of water for 96 hours, so the values are applicable to specific design requirements only when the end-use conditions are similar to test method requirements.  b not part of the industry consensus standards (ASTM, CAN/ULC) and provided AS-IS solely for informational purposes

The Canadian CAN/ULC-S701 "Standard for Thermal Insulation, Polystyrene, Boards and Pipe Covering" provides material properties of various EPS Types:

Property** Units CAN/ULC-S701 Types ASTM Test
1
2
3
Compressive Resistance
Minimum @ 10% Deformation
kPa 70 110 140 D1621
Proc.A
psi 10 16 20
Thermal Resistance*
RSI / 25mm thickness
Minimum @ 24°C
m²•°C/ (W•25mm)0.650.700.74 C518
Thermal Resistance*
R-Value / inch thickness
Minimum @ 75°F
ft²•hr•°F/ (BTU•in)3.754.044.27 C518
Flexural Strength
Minimum
kPa 170 240 300 C203
Proc.B
psi 25 35 44
Water Vapor Permeance*
Maximum at 25mm [1inch] thickness
ng/(Pa•s•m²)300200130 E96
perms5.23.22.3
Water Absorption
Maximum
% by
volume
6.0 4.0 2.0 D2842
Dimensional Stability % linear
change max.
1.51.51.5 D2126 7 Days
@ 70±2°C
Limiting Oxygen Index % min.242424 D2863

* Values are for 25.4mm [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.

The American ASTM C578 "Standard Specification for Rigid, Cellular Polystyrene Thermal Insulation" provides material properties of various EPS Types:

Property Units ASTM C578 Types ASTM Test
I
VIII
II
IX
XIV
Compressive Resistance²
Minimum @ 10% Deformation
psi 10 13 15 25 40 D1621
Proc.A
kPa 69 90 103 172 276
Thermal Resistance1,2,3
R-Value / inch thickness
Minimum @ 75°F [24°C]
ft²•hr•°F/ (BTU•in) 3.6 3.8 4.0 4.2 4.2 C518
Flexural Strength²
Minimum
psi 25 30 35 50 60 C203
Proc.B
kPa 173 208 270 345 414
Water Vapor Permeance1,2
Maximum at 1inch [25mm] thickness
perms 5.0 3.5 3.5 2.5 2.5 E96
ng/(Pa•s•m²) 286 200 200 143 143
Water Absorption²
Maximum
% by
volume
4 3 3 2 2 D2842
Dimensional Stability² % linear
change max.
2 2 2 2 2 D2126 7 Days
@ 70±2°C
Limiting Oxygen Index² % min. 24 24 24 24 24 D2863
Density - Nominal lbs/ft³ (PCF) 1 2  
Density²
Minimum
lbs/ft³ (PCF) 0.9 1.15 1.35 1.8 2.4 C303 or D1622
kg/m³ 14.4 18.4 21.6 28.8 38.4
Thermal Resistance at Additional Mean Temperatures C518
R-Value / inch thickness
Minimum ft²•hr•°F/ (BTU•in)
@ 40°F [4.4°C] 4.0 4.2 4.4 4.6 4.6
@ 25°F [-4°C] 4.2 4.4 4.6 4.8 4.8

¹ Values are for 1 inch [25.4mm] thick samples with natural skins intact. Better values will result for thicker materials.  ² 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. ³ R means resistance to heat flow. The higher the R-value, the greater the insulating power.

Additional Properties of EPS

Expanded polystyrene (EPS) resists mold & fungi per ASTM C1338 and has no nutritional value for insects. To protect against termites place adequate physical barriers such as membranes around below-grade EPS.
Max. service temperature: Long-Term Exposure 75°C [167°F]; Intermittent Exposure 80°C [176°F] Thermal expansion coefficient: 5-7 • 10-5/°K
Limiting Oxygen Index: min. 24% per ASTM D2863. Airfoam's EPS for construction applications contains a polymeric (non-HBCD) flame-retardant modifier.
Surface Burning Characteristics: CAN/ULC-S102: Flame Spread ≤290, Smoke Developed over 500.   USA ASTM E84ª: FSI ≤75, SDI ≤450
Solubility: Insoluble in water and in general chemically inert. EPS dissolves in hydrocarbons (e.g. fuels, oils, tar), organic solvents (e.g. acetone/ketones, benzene, paint thinner), ethers, esters, aldehydes and amines. Capillarity: None
UV-light surface degradation: white 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, see SDS
CAUTION: EPS products are combustible and must not be exposed to excessive heat, sparks, open flames, or any other sources of ignition. If stored/used in closed containers, confined, or low-lying areas, ensure adequate ventilation to prevent accumulation of flammable pentane vapours. Prevent inhalation of smoke, fumes or dust from burning or fabrication activities. In addition, a protective barrier or thermal barrier is required to separate EPS products from interior living or conditioned spaces as specified in the appropriate building code.

ª Ceiling measurement only, conducted through determination of flame spread index and smoke developed index with the removal of any contribution of molten materials ignited on the floor of the Steiner tunnel.