Reliability of Transient Heat and Moisture Modeling for Hygroscopic Buffering

Numerical models of heat, air and moisture (HAM) transfer in building components continue to advance, but there remains a need for accurate and well-documented experimental data for model validation. In the framework of IEA/ECBCS Annex 41 a round robin experiment on the determination of the hygric properties of porous building materials was combined with a transient heat and moisture transfer experiment to generate a data set for benchmarking numerical models. In the round robin experiment fourteen laboratories measured the vapor permeability and sorption isotherm of coated and uncoated gypsum board. In the second part, ten different numerical models used the mean values of the measured material properties to simulate the dynamic behaviour of a bed of gypsum board as measured in a transient moisture transfer facility. The combination of round robin and dynamic experiments also allowed a sensitivity study of the numerical simulations, in which the influence of the uncertainty in material properties and boundary conditions were investigated.