- General Interest
Insulation performance is influenced by many factors the most prominent of which include:
- Thermal conductivity ("k" or "λ" value)
- Surface emissivity ("ε" value)
- Insulation thickness
- Specific heat capacity
- Thermal bridging
It is important to note that the factors influencing performance may vary over time as material ages or environmental conditions change.
The effect of density on product properties varies from one insulation material to another and this is valid even within the group of different mineral wool insulation materials (glasswool, stone wool, Ultimate). Therefore it is not ideal to just compare material performance solely by their density.
Ultimate products have a lower density and consequently a lower weight when compared to traditional solutions such as stone wool.
For example stone wool Wired Mat 90kg/m³ is heavier than Ultimate Wired Mat 66kg/m³. But the Ultimate product performs to the same efficiency if not greater. Whilst being easier to install and easier to handle./
Weight itself is not the only parameter influencing thermal performance. Other characteristics in mineral wool can have even bigger influence in thermal performance (fibre orientation, shot content, diameter of fibres, length of fibres, chemical composition)
Thermal conductivity is the measure to look at when speaking about heat transfer. In the case of mineral wool, the thermal insulation quality of the materials depends mainly on the respective fiberisation process and the mats structure. During the production of glass wool and Ultimate the raw material is 100% transferred into the wool. In comparison, the stone wool process creates a significant share of shots (unfiberised pieces) that are add to the weight but do not have a positive impact on the thermal or acoustic properties of the final product. Within stone wool material up to 20% of the product does not contribute to the strength or thermal performance. It is more likely that this 20% of unfiberised material will actually detract from the thermal performance.
Ultimate uses 100% of its material, which contributes to making the product more effective in both compression strength and lambda.
Another misconception is that compression strength is related to density, when there is no connection.
It is therefore important to always take into account the application and its specific requirements when choosing an insulation material.