An experimental investigation into the comparative hygrothermal performance of wall panels incorporating wood fibre, mineral wool and hemp-lime

Three wall panels of identical calculated U-value were simultaneously assessed in a large dual environmental chamber under a number of steady state and dynamic hygrothermal boundary conditions. This study used large-scale wall elements under identical controlled conditions in order to eliminate uncontrollable variables normally encountered in full-scale studies. The following panels were tested: Mineral Wool Panel, Wood Fibre Panel and the Biond Panel (an assembly of wood fibre and hemp-lime). Within the limits of the error range of the calculation, the measured U-value was same for all test panels when assessed under steady state and dynamic hygrothermal boundary conditions. It was however observed that in a boundary condition simulating intermittent heating, the Biond panel showed the highest heat storing and releasing capability whereas the Mineral Wool Panel showed the lowest. In terms of moisture management, the Biond panel exhibited the highest moisture dampening ability within the panel structure. Higher thermal and hygric inertia of the Biond panel may be useful in mitigating overheating of dwellings and reducing interstitial condensation.