What Is the Density of Calcium Silicate Insulation Board?
Calcium silicate insulation board is manufactured across a wide density range from 170 to 900 kg/m³. Density is the primary factor determining compressive strength, thermal conductivity, and suitable applications. Selecting the correct density for your application is essential for both performance and cost-effectiveness.
Density Grades and Applications
| Density Class | Typical Density (kg/m³) | Compressive Strength (MPa) | Best For |
|---|---|---|---|
| Low Density | 170 - 230 | 1.5 - 2.5 | General thermal insulation where weight matters; pipe insulation sections |
| Medium Density | 230 - 400 | 2.5 - 5.0 | Standard industrial insulation; vessel and tank insulation |
| High Density | 400 - 600 | 5.0 - 10.0 | Load-bearing backup insulation behind refractory; furnace linings |
| Ultra-High Density | 600 - 900 | 10.0 - 17.0 | Fire door cores; structural fire protection; screw-retention applications |
How Density Affects Performance
Density is controlled during the filter pressing stage of manufacturing. Higher pressing pressure removes more water, producing a denser board with higher compressive strength but slightly higher thermal conductivity. This tradeoff means that for pure thermal insulation where no load is applied, a low-density board is most efficient. For load-bearing applications, you must specify a density high enough to handle the compressive load without crushing.
Density and Thermal Conductivity
There is a U-shaped relationship between density and thermal conductivity. At very low densities (below 170 kg/m³), the pore structure is too open and radiative heat transfer increases thermal conductivity. At very high densities (above 600 kg/m³), solid conduction paths through the material increase thermal conductivity. The optimal range for insulation efficiency is approximately 200-300 kg/m³, which is where Mingfa positions its standard insulation grades.
How to Specify Density
When requesting a quotation, specify the required density class (not just "calcium silicate board"). Tell us the application, service temperature, and any compressive load. Our technical team can recommend the right density grade. Browse our products page for standard density options, or contact us for custom density requirements.