Karagiozis, A.A.KaragiozisDesjarlais, A.A.DesjarlaisKünzel, H.M.H.M.KünzelHolm, A.A.Holm2022-03-042022-03-042010https://publica.fraunhofer.de/handle/publica/223301Our current state-of-the-art construction design approach is to integrate principles of sustainable design. The philosophy of sustainable building construction relies on designing physical objects, the built environment and services to comply with the principles of economic, social and ecological sustainability. This requires the architect to design with low-impact environmental materials, energy-efficiency (embodied and operations) and quality and durability (longer-lasting and higherperformance) to create healthy buildings (a good indoor environment) and recycling potential. From the above disciplines of sustainable design, heat, air and moisture processes (HAM) play a critical role in developing the necessary yardstick for energy-efficiency, durability and healthy buildings. Energy-efficiency and comfort have recently been two main considerations in building designs, while durability has always been a critical parameter. Yet, until recently, no HAM design tools/methods were readily available. Recently, the increasing demand for better-performing calculation methods to assess the moisture behavior of building components prompted an international collaboration between the Oak Ridge National Laboratory (ORNL) in the United States and the Fraunhofer Institute for Building Physics (IBP) in Germany to develop a hygrothermal design tool named WUFI-ORNL/IBP. This hygrothermal design model can assess the response of building envelope systems in terms of heat and moisture loads and can also provide a very useful and fair method for evaluating and optimizing building envelope designs. Today, if architects and engineers do not use the WUFI (Wärme und Feuchte instationär) hygrothermal model for building envelope design, or WUFI-Plus for the whole building de sign, they are assuming unnecessary field failure risks for themselves and their clients.en690journal article