What is the maximum thermal conductivity allowed by this standard?

The maximum thermal conductivity is 0.040 W/m.K when tested at a mean temperature of 10°C, as per Table 1.

What is the minimum required compressive strength?

The minimum compressive strength at 10 percent deformation is 100 kPa (or 1.0 kgf/cm²), according to Table 1.

What are the fire performance requirements?

The material must have a maximum rate of burning of 150 mm/min when tested as per the method in Appendix A-11.

Does this standard specify the density?

No, it does not specify a mandatory density. It requires the 'Apparent Density' to be declared by the manufacturer and to be within ±10% of the declared value (Table 1).

IS 9789

: 1981

Specification for rigid cellular phenolic foam for thermal insulation

CurrentSpecializedSpecificationMEP · Insulation Materials

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This specification outlines the requirements and test methods for rigid cellular phenolic foam intended for thermal insulation applications. It covers essential physical properties such as density, thermal conductivity, compressive strength, water absorption, and flammability to ensure material quality and performance.

Specifies requirements for rigid cellular phenolic foam used for thermal insulation.

Quick Reference Values

Maximum Thermal Conductivity (at 10°C mean temp)0.040 W/m.K

Minimum Compressive Strength (at 10% deformation)100 kPa

Maximum Water Vapour Transmission4.5 Perms

Maximum Water Absorption (24h immersion)0.1 kg/m²

Minimum Closed Cell Content90%

Maximum Flammability (Rate of burning)150 mm/min

Practical Notes

Phenolic foam is known for its excellent fire resistance properties but can be more brittle than other foam insulations; handle with care during installation.

Verify the compatibility of adhesives, sealants, and facing materials, as certain solvents can chemically attack and degrade the foam.

The standard has been superseded by IS 12436, which should be referred to for new projects, though IS 9789 may be cited in older project specifications.