What is the primary purpose of IS 3346?

To standardize the terminology and definitions used across the thermal insulation industry to prevent ambiguity.

Does this standard provide minimum required R-values or insulation thicknesses?

No, it only provides terminology definitions. Required R-values or U-values are found in design codes like the Energy Conservation Building Code (ECBC) or specific material codes.

How does it define Thermal Transmittance (U-value)?

As the overall rate of heat transfer through a unit area of a building element or structure per degree of temperature difference between the environments on either side.

IS 3346

: 1980

Glossary of terms relating to thermal insulation

CurrentSpecializedTerminologyMEP · Insulation Materials

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This standard provides a comprehensive glossary of terms relating to thermal insulation. It establishes standard definitions for concepts involving heat transmission, insulating materials, and their properties to ensure uniformity in technical literature and specifications.

Defines terms and symbols related to thermal insulation materials and systems.

Quick Reference Values

Thermal Conductivity (k) unitW/(m·K)

Thermal Resistance (R) unitm²·K/W

Thermal Transmittance (U) unitW/(m²·K)

Thermal Diffusivity unitm²/s

Practical Notes

Commonly used by specifiers and HVAC engineers to standardize contractual language and technical specifications.

Helps clarify the critical technical distinction between material properties (like thermal conductivity) and system properties (like thermal transmittance or U-value).