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IS 9091 : 2020Expanded polystyrene (EPS) boards for thermal insulation - Specification

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EN 13163 · ASTM C578 · BS EN 13163
CurrentSpecializedSpecificationBIMArchitectural · Roofing Materials
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OverviewValues7InternationalTablesFAQ4Related

IS 9091:2020 is the Indian Standard (BIS) for expanded polystyrene (eps) boards for thermal insulation - specification. This standard specifies the requirements, dimensions, sampling, and testing methods for expanded polystyrene (EPS) boards used for thermal insulation. It classifies EPS boards into different types based on physical properties like density and compressive strength, ensuring their performance for energy conservation in buildings and industrial applications like cold storage.

Specifies requirements for expanded polystyrene boards used for thermal insulation.

Overview

Status
Current
Usage level
Specialized
Domain
Architectural — Roofing Materials
Type
Specification
Earlier editions
IS 9091:1993
International equivalents
EN 13163:2012+A2:2016 · CEN (European Committee for Standardization), EuropeASTM C578-21 · ASTM International, USABS EN 13163:2012+A2:2016 · BSI (British Standards Institution), UKISO 4898:2018 · ISO (International Organization for Standardization), International
Typically used with
IS 7888IS 4671IS 9845
Also on InfraLens for IS 9091
7Key values3Tables4FAQs

BIM-relevant code. See the BIM Hub for ISO 19650, IFC, and LOD/LOIN frameworks used alongside it.

Practical Notes
! Specify the correct density/type (e.g., Normal Duty, High Duty) based on the application's compressive load requirements (e.g., roof vs. wall).
! Always specify and use the Self-Extinguishing (SE) grade for building envelope applications to comply with fire safety norms.
! Protect boards from prolonged UV exposure (direct sunlight) and physical damage on-site to prevent surface degradation and maintain dimensional stability.
Frequently referenced clauses
Cl. 5RequirementsCl. 6Dimensions and TolerancesCl. 7Sampling and Criteria for ConformityAnnex A - Method for Determination of Thermal ConductivityAnnex C - Flammability Test
Pulled from IS 9091:2020. Browse the full clause & table index below in Tables & Referenced Sections.
expanded polystyreneEPSthermal insulationpolymers

International Equivalents

Similar International Standards
EN 13163:2012+A2:2016CEN (European Committee for Standardization), Europe
HighCurrent
Thermal insulation products for buildings - Factory made expanded polystyrene (EPS) products - Specification
Both standards specify requirements for factory-made EPS boards used for thermal insulation in buildings.
ASTM C578-21ASTM International, USA
HighCurrent
Standard Specification for Rigid, Cellular Polystyrene Thermal Insulation
Covers rigid cellular polystyrene, including EPS, for thermal insulation in various construction applications.
BS EN 13163:2012+A2:2016BSI (British Standards Institution), UK
HighCurrent
Thermal insulation products for buildings. Factory made expanded polystyrene (EPS) products. Specification
Identical scope to EN 13163, specifying requirements for factory-made EPS boards in the UK market.
ISO 4898:2018ISO (International Organization for Standardization), International
MediumCurrent
Rigid cellular plastics — Thermal insulation products for buildings — Specifications
Provides a framework for specifying rigid cellular plastics, with EPS being one type covered, but is less detailed than national/regional standards.
Key Differences
≠Classification System: IS 9091 classifies products into four grades (SE, N, H, VH) based primarily on nominal density. In contrast, EN 13163 uses a performance-based designation code system (e.g., CS(10)100 for 100 kPa compressive strength), and ASTM C578 uses Types (e.g., Type I, II, IX) linked to minimum compressive strength and density.
≠Fire Performance Classification: IS 9091 mandates a simple 'Self-Extinguishing' property test as per IS 6746. EN 13163 uses the comprehensive European Reaction to Fire classification system (Euroclasses A1 to F), which evaluates multiple factors like flame spread, smoke production, and flaming droplets.
≠Thermal Conductivity Declaration: IS 9091 specifies fixed maximum thermal conductivity values for each density grade. EN 13163 requires manufacturers to declare a design lambda value (λD) based on a statistical '90/90' principle (90% fractile with 90% confidence), which provides a more product-specific and reliable thermal performance figure.
≠Regulatory Framework: EN 13163 is a harmonized standard under the EU Construction Products Regulation (CPR), requiring a Declaration of Performance (DoP) and CE marking. IS 9091 is a national standard governed by the Bureau of Indian Standards (BIS) certification scheme, requiring the ISI mark.
Key Similarities
≈Core Material and Application: All standards cover the same fundamental material (rigid expanded polystyrene) and are intended for the primary application of thermal insulation in building construction (roofs, walls, floors).
≈Fundamental Properties Specified: All standards define requirements for a core set of properties critical for performance, including density, compressive strength, bending strength (flexural strength), thermal conductivity, dimensional stability, and water absorption.
≈Dimensional Tolerances: All standards specify acceptable tolerance limits for the physical dimensions of the boards, such as length, width, thickness, squareness, and flatness, to ensure product quality and proper installation.
≈Test Methods: Many of the underlying test methods for determining properties like compressive strength (ISO 844), thermal conductivity (ISO 8301/8302), and dimensional stability are based on the same or very similar ISO standards, ensuring a degree of consistency in measurement.
Parameter Comparison
ParameterIS ValueInternationalSource
Nominal Density15.0 - 18.0 kg/m³ (for 'N' Grade)14.4 kg/m³ (minimum for Type I)ASTM C578-21
Compressive Stress @ 10% Deformation≥ 60 kPa (for 'N' Grade)≥ 60 kPa (for designation level CS(10)60)EN 13163
Bending Strength≥ 100 kPa (for 'N' Grade)≥ 100 kPa (for designation level BS100)EN 13163
Thermal Conductivity (max at 10°C)≤ 0.042 W/(m·K) (for 'N' Grade)Declared λD, typically 0.036-0.038 W/(m·K) for comparable productsEN 13163
Water Absorption (by total immersion)≤ 3.0 % by volume (after 24 h)≤ 4.0 % by volume (after 24 h, for Type I)ASTM C578-21
Thickness Tolerance±1 mm (up to 50 mm thick)±1 mm (for tolerance class T1)EN 13163
Dimensional Stability (Length/Width under heat/humidity)≤ 0.5% (at 70°C, 90% RH, 48h)≤ 0.5% (for designation level DS(70,90)0,5)EN 13163
⚠ Verify details from original standards before use

Key Values7

Quick Reference Values
Minimum Density (Normal Duty)15 kg/m³
Minimum Compressive Strength at 10% deformation (Normal Duty)60 kPa
Maximum Thermal Conductivity (Normal Duty)0.042 W/(m·K)
Maximum Water Absorption (by partial immersion)0.5 kg/m²
Dimensional Tolerance (Length/Width)± 2.0 mm
Dimensional Tolerance (Thickness)± 1.0 mm
Fire Performance RequirementMaterial shall be of self-extinguishing type

Tables & Referenced Sections

Key Tables
Table 1 - Physical Requirements of Expanded Polystyrene for Thermal Insulation
Table 2 - Dimensional Tolerances for Boards
Table 3 - Scale of Sampling and Permissible Number of Defectives
Key Clauses
Clause 5 - Requirements
Clause 6 - Dimensions and Tolerances
Clause 7 - Sampling and Criteria for Conformity
Annex A - Method for Determination of Thermal Conductivity
Annex C - Flammability Test

Related Resources on InfraLens

Cross-Referenced Codes
IS 7888:1996Glazed Stoneware Pipes and Fittings
→
IS 4671:1980Specification for calcium silicate preformed ...
→
IS 9845:2006Determination of Aggregate Impact Value
→

Frequently Asked Questions4

What are the main types of EPS boards in this standard?+
The standard classifies boards based on density and compressive strength, typically as Normal Duty (ND), High Duty (HD), and Very High Duty (VHD), with an optional Self-Extinguishing (SE) fire-retardant property.
What is the maximum thermal conductivity for normal duty EPS?+
For normal duty (Type ND, ~15 kg/m³), the maximum thermal conductivity is specified as 0.042 W/(m·K) in Table 1.
Are there specific dimensional tolerances for EPS boards?+
Yes, Table 2 specifies tolerances for length/width (typically ±2 mm) and thickness (typically ±1 mm), which are critical for achieving tight fits and avoiding thermal bridges.
Is EPS board flammable?+
The standard requires that EPS boards for most building applications be of a self-extinguishing (SE) type, which is verified by a flammability test (Annex C).

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