Measured Thermal Resistance of Frame Walls with Defects in the Installation of Mineral Fibre Insulation

Studies have shown that convective air flow can significantly reduce the thermal resistance of frame walls insulated with mineral fibre insulation (MFI). It has also been shown that convective air flow can be avoided if the MFI products are installed with at least one face against an air impermeable material. The evolution of MFI products has seen the introduction of products with smaller fibre diameters and lighter densities, and there is a dominance of the frame wall insulation market by fric tion fit products. The effect of these changes on the installed (field) performance of MFI products is unknown, as is the effect of "minor" installation defects on the per formance of frame wall insulation systems. This article examines, through a program of full scale laboratory measurements, the effect of corner installation defects and product density on the thermal resistance of frame walls insulated with MFI prod ucts.