What is the primary difference between PUR and PIR specified in this code?

PIR is a chemically modified form of PUR that exhibits higher thermal stability and significantly better fire-retardant properties, as reflected in the higher minimum Oxygen Index requirement (Clause 3 and Table 1).

What is the maximum thermal conductivity allowed?

The maximum initial thermal conductivity is 0.021 W/(m.K) when measured at a mean temperature of 10°C (Table 1).

Is this material suitable for load-bearing applications?

It has limited load-bearing capacity. The minimum compressive strength is 150 kPa at 10% deformation, suitable for floor insulation under screed but not for direct structural loads (Table 1).

What are the fire performance requirements?

The material must achieve 'Class 1' in the surface spread of flame test. Additionally, PIR foam must have a minimum Oxygen Index of 24% (Table 1).

IS 14227

: 2018

Rigid Polyurethane (PUR) and Polyisocyanurate (PIR) Foam for Thermal Insulation - Specification

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This standard specifies the requirements and test methods for rigid polyurethane (PUR) and polyisocyanurate (PIR) foam used for thermal insulation. It covers essential properties like thermal conductivity, density, compressive strength, dimensional stability, and fire performance for foam supplied in blocks, boards, or other pre-formed shapes.

Specifies requirements for rigid polyurethane (PUR) and polyisocyanurate (PIR) foam boards and blocks used as thermal insulation materials.

Quick Reference Values

Maximum Initial Thermal Conductivity at 10°C0.021 W/(m.K)

Minimum Compressive Strength at 10% deformation150 kPa

Minimum Closed Cell Content90 %

Maximum Water Vapour Permeability4.5 ng/(Pa.s.m)

Minimum Oxygen Index for PIR24 %

Apparent Core Density Range36 - 45 kg/m³

Practical Notes

PIR foam generally provides superior fire resistance and dimensional stability compared to PUR foam, making it preferable for applications with stricter fire codes.

The thermal conductivity (k-value) can increase over time due to the diffusion of blowing agents. Always consider the aged k-value provided by the manufacturer for long-term energy performance calculations.

Ensure the insulation is installed with a continuous and properly sealed vapour barrier, especially in cold applications, to prevent interstitial condensation and degradation of thermal performance.