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IS 11206:1985 is the Indian Standard (BIS) for extruded polystyrene (xps) for thermal insulation. This standard specifies the requirements, testing methods, and sampling procedures for rigid extruded polystyrene (XPS) boards intended for thermal insulation. It classifies XPS into five types based on compressive strength and details mandatory physical properties such as density, thermal conductivity, water absorption, and dimensional stability. The code serves as a benchmark for manufacturers and for quality assurance in construction projects.
Specifies requirements for extruded polystyrene (XPS) products used for thermal insulation.
BIM-relevant code. See the BIM Hub for ISO 19650, IFC, and LOD/LOIN frameworks used alongside it.
Practical Notes
! Ensure material is protected from prolonged direct sunlight (UV exposure) which can degrade the surface, a factor not covered in detail by this standard.
! While the code specifies minimum compressive strength, select a higher grade for applications with significant loads, such as inverted roofs or under-slab insulation.
! Always verify the manufacturer's test certificate against the requirements of Table 1, paying close attention to the thermal conductivity (k-value) which is critical for performance.
Broader scope covering various rigid cellular plastics, with XPS being one of the types.
BS EN 13164:2012+A1:2015BSI (British Standards Institution), UK
HighCurrent
Thermal insulation products for buildings. Factory made extruded polystyrene foam (XPS) products. Specification
The UK's national adoption of the European standard EN 13164, making it identical in technical content.
Key Differences
≠IS 11206 defines a single type of XPS based on a minimum density, whereas EN 13164 and ASTM C578 define multiple types/levels based on performance characteristics, primarily compressive strength, allowing for a wider range of applications.
≠The Indian standard specifies an initial thermal conductivity value. Modern standards like EN 13164 mandate the declaration of aged thermal conductivity values, which account for the long-term degradation of performance as blowing agent gas diffuses out.
≠Water absorption limits are significantly different. IS 11206 allows up to 1.0% by volume, while a comparable grade in ASTM C578 allows a maximum of only 0.3%, indicating a stricter requirement in the international standard.
≠EN 13164 and ASTM C578 include requirements for properties not covered in IS 11206:1985, such as long-term water absorption by diffusion, freeze-thaw resistance, and deformation under specified load and temperature conditions.
Key Similarities
≈All standards define the material as a rigid, closed-cell foam plastic manufactured through an extrusion process using polystyrene or one of its copolymers.
≈The fundamental purpose across all standards is to specify requirements for XPS used as thermal insulation in building applications.
≈All standards establish mandatory requirements for key physical properties, including density, thermal conductivity, compressive strength, and water absorption, forming the basis for product acceptance.
≈Specifications for dimensional tolerances (length, width, thickness, and squareness) are included in all standards to ensure product consistency and fit during installation.
Parameter Comparison
Parameter
IS Value
International
Source
Density
≥ 32 kg/m³
≥ 28.8 kg/m³ (for Type IV)
ASTM C578-21
Compressive Strength (at 10% deformation)
≥ 250 kPa
≥ 250 kPa (for Level CS(10\Y)250)
EN 13164:2012+A1:2015
Thermal Conductivity (max, at 10°C mean temp)
0.027 W/(m·K) (initial value)
Typically 0.029 - 0.034 W/(m·K) (declared aged value, varies by thickness)
EN 13164:2012+A1:2015
Water Absorption (by full immersion, % vol)
≤ 1.0%
≤ 0.7% (for products ≤ 50mm thick)
EN 13164:2012+A1:2015
Water Absorption (by full immersion, % vol)
≤ 1.0%
≤ 0.3% (for Type IV)
ASTM C578-21
Dimensional Stability (Linear change)
≤ 1.5% (at 70°C, 7 days)
≤ 5% (at 70°C, 48 hours)
EN 13164:2012+A1:2015
Water Vapour Transmission Rate (max)
Not specified
≤ 3.5 Perms (57.5 ng/Pa·s·m²) (for Type IV)
ASTM C578-21
⚠ Verify details from original standards before use
Key Values7
Quick Reference Values
Maximum Thermal Conductivity (at 10°C mean temp)0.029 W/m.K
Minimum Compressive Strength (Type XPS 200)200 kPa at 10% deformation
Nominal Density (Type XPS 200)28 kg/m³
Maximum Water Absorption1.5% by volume
Maximum Water Vapour Transmission4.5 ng/Pa.s.m
Minimum Closed Cell Content90 %
Maximum Dimensional Change (at 70°C, 48h)3.0 %
Tables & Referenced Sections
Key Tables
Table 1 - Physical Requirements of Extruded Polystyrene
What are the different types of XPS defined in this standard?+
The standard classifies XPS into five types based on nominal compressive strength at 10% deformation: XPS 150, XPS 200, XPS 250, XPS 350, and XPS 500 (Clause 3.1).
What is the maximum allowed thermal conductivity (k-value)?+
For most common types (density 28-35 kg/m³), the maximum thermal conductivity is 0.029 W/m.K when measured at a mean temperature of 10°C (Table 1).
What is the maximum water absorption for XPS boards under this IS code?+
The maximum water absorption is 1.5% by volume when tested as per the specified method (Table 1).
Are there standard sizes for XPS boards?+
The standard does not specify fixed sizes but states they shall be supplied in lengths and widths as agreed between the purchaser and supplier, with thickness ranging from 20 to 100 mm (Clause 4.1).