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IS 17409:2020 is the Indian Standard (BIS) for flexible elastomeric foams for thermal insulation - specification. This standard specifies the requirements for factory-made flexible elastomeric foam (FEF) products used for thermal insulation of building equipment and industrial installations, such as pipes, ducts, and vessels. It defines key properties like thermal conductivity, water vapor resistance, fire performance, and dimensional tolerances, and establishes a designation code system for product classification.
Specifies requirements for flexible elastomeric foams used for thermal insulation.
BIM-relevant code. See the BIM Hub for ISO 19650, IFC, and LOD/LOIN frameworks used alongside it.
Practical Notes
! The 'μ-value' (water vapor diffusion resistance factor) is critical. A high value (≥ 7000) is essential to prevent interstitial condensation on cold pipes and ducts, which can degrade insulation and cause corrosion.
! Ensure the product's fire performance rating meets project and statutory requirements (e.g., National Building Code), especially for applications in plenums or occupied spaces.
! Proper installation with compatible adhesives is as important as the material itself. Gaps or poor sealing will severely compromise the insulation system's performance.
Standard Specification for Preformed Flexible Elastomeric Cellular Thermal Insulation in Sheet and Tubular Form
Covers flexible, closed-cell elastomeric foam for thermal insulation in sheet and tubular forms.
EN 14304:2015+A1:2021CEN (European Committee for Standardization), Europe
HighCurrent
Thermal insulation products for building equipment and industrial installations - Factory made flexible elastomeric foam (FEF) products - Specification
Specifies requirements for factory-made flexible elastomeric foam products used for thermal insulation.
ISO 20389-1:2018ISO (International Organization for Standardization), International
HighCurrent
Thermal insulation products for building applications — Part 1: Specification for factory-made flexible elastomeric foam (FEF) products
Harmonized standard specifying requirements for flexible elastomeric foam products for building insulation.
Key Differences
≠Fire performance classification is a major difference. IS 17409 refers to Indian tests like IS 15061, while EN 14304 uses the Euroclass system (A1-F) based on EN 13501-1, and ASTM C534 specifies Flame Spread Index and Smoke Developed Index per ASTM E84.
≠Product classification varies. IS 17409 classifies products into Class O, 1, and 2 based on the upper service temperature. ASTM C534 uses Type I (tubular) and Type II (sheet), while EN 14304 uses a detailed designation code system for manufacturers to declare performance levels for multiple properties.
≠The expression of water vapour resistance differs. IS 17409 and EN 14304 specify a dimensionless Water Vapour Diffusion Resistance Factor (µ-value), whereas ASTM C534 specifies a maximum Water Vapor Permeability value in 'perm-inch' (ng/Pa·s·m).
Key Similarities
≈All standards cover the same fundamental material: preformed, closed-cell, flexible elastomeric foam intended for thermal insulation.
≈The scope of all standards includes both tubular and sheet forms of the insulation material, designed for application on pipes and flat surfaces.
≈Core physical properties such as thermal conductivity, dimensional stability, and service temperature range are key requirements across all compared standards.
≈The test methods for determining thermal conductivity are based on similar principles, typically using a guarded hot plate or heat flow meter apparatus at specified mean temperatures.
Parameter Comparison
Parameter
IS Value
International
Source
Thermal Conductivity (λ) at 40°C mean temp.
≤ 0.040 W/(m·K) (for Class O & 1)
≤ 0.040 W/(m·K) is a common declared value
EN 14304:2015
Water Vapour Diffusion Resistance Factor (µ)
≥ 7000 (for Class O & 1)
≥ 7000 or ≥ 10000 are common declared levels
EN 14304:2015
Upper Service Temperature Limit (Class 1)
+105°C
+104°C (+220°F) is a typical requirement
ASTM C534/C534M - 14
Lower Service Temperature Limit
-40°C
-57°C (-70°F)
ASTM C534/C534M - 14
Dimensional Stability (Shrinkage) @ 7 days
≤ 7% (at 105°C for Class 1)
≤ 7% (at 104°C)
ASTM C534/C534M - 14
Apparent Density (Core)
40 - 80 kg/m³ (Informative)
48 - 160 kg/m³ [3.0 - 10.0 lb/ft³] (Mandatory)
ASTM C534/C534M - 14
Water Absorption by Volume
≤ 5 %
≤ 0.2 % by volume
ASTM C534/C534M - 14
⚠ Verify details from original standards before use
Key Values6
Quick Reference Values
Maximum Thermal Conductivity at 20°C mean temp0.038 W/(m·K)
Minimum Water Vapour Diffusion Resistance Factor (μ)7000
Maximum Service Temperature+105 °C
Minimum Service Temperature-50 °C
Minimum Limiting Oxygen Index (LOI)26 %
Maximum Longitudinal Shrinkage7 %
Tables & Referenced Sections
Key Tables
Table 1 - Requirements for Physical Properties of Flexible Elastomeric Foam
Table 2 - Tolerances on Length, Width and Thickness of Sheets and Rolls
Table 3 - Tolerances on Thickness and Length of Tubes
Table 4 - Test Methods, Test Specimen and Conditions
Key Clauses
Clause 4 - Requirements
Clause 6.2 - Thermal Conductivity
Clause 6.3 - Water Vapour Diffusion Resistance Factor
What is the most important property for this insulation material?+
Thermal conductivity (k-value). A lower value means better insulation performance. The standard mandates a maximum of 0.038 W/(m·K) at a mean temperature of 20°C (Table 1).
How do I prevent water vapor from getting into the insulation on a cold pipe?+
Select a product with a high Water Vapour Diffusion Resistance Factor (μ-value). The standard requires a minimum μ of 7000 (Table 1), which indicates high resistance to moisture ingress.
What does the fire rating in this standard mean?+
It refers to the material's 'Reaction to Fire', primarily measured by the Limiting Oxygen Index (LOI). A minimum LOI of 26% is required (Table 1), indicating the material needs a higher concentration of oxygen to burn and will self-extinguish in normal air.
Does this standard cover installation?+
No, IS 17409 is a product specification for the material itself. Installation procedures should follow manufacturer's guidelines and relevant codes of practice.