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.

IS 17409

: 2020

Flexible Elastomeric Foams for Thermal Insulation - Specification

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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.

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 %

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.