What is the purpose of a vapour barrier?

For cold insulation, it prevents moisture from ambient air from entering the insulation and condensing, which would compromise thermal performance and cause corrosion (Clause 7.5).

How is insulation thickness determined?

The code provides recommended thicknesses in tables (e.g., Table 2, 3, 4) based on pipe/duct size, operating temperature, and insulation material to achieve a desired heat loss or surface temperature (Clause 6).

What insulation is used for high temperatures, like 500°C?

Calcium silicate (up to 650°C) or bonded mineral wool (up to 750°C) are common choices as per Table 1.

Is it necessary to insulate valves and flanges?

Yes, it is essential to insulate valves, flanges, and fittings to prevent significant localized heat loss/gain. Removable insulation covers are recommended for these components (Clause 7.2.5).

IS 8229

: 1994

Code of practice for thermal insulation of pipes, ducts and equipment

CurrentFrequently UsedCode of PracticeBIMMEP · Insulation Materials

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This standard is a code of practice for the selection and application of thermal insulation on pipes, ducts, and equipment for both hot and cold services. It aims to conserve energy, maintain process temperatures, prevent condensation, and ensure personnel safety by controlling surface temperatures.

Provides a code of practice for the thermal insulation of pipes, ducts, and industrial equipment.

Quick Reference Values

Thermal conductivity of mineral wool (at 50°C mean)0.036 W/m.K

Max service temperature for calcium silicate650 °C

Max service temperature for flexible elastomeric foam105 °C

Density of preformed calcium silicate<= 225 kg/m³

Typical thickness for 100mm pipe at 200°C50 mm

Key Formulas

Economic Thickness of Insulation = The thickness where the total cost (insulation cost + capitalized cost of heat loss) is minimized.

Practical Notes

For cold insulation, the integrity of the vapour barrier is paramount. Any puncture or improperly sealed joint will lead to moisture ingress, ice formation, and ultimately, failure of the insulation system.

Ensure insulation is not compressed during installation, as compression increases its density and thermal conductivity, reducing its effectiveness.

Always use removable insulation boxes for flanges, valves, and other components that require regular maintenance to avoid repeated damage to the main insulation.