Page 54 - Build 151

Internal moisture
A fresh look at WUFI
WUFI Development, a new Building Research Levy-funded project at BRANZ, aims to further enhance the heat and moisture tool’s usefulness for local users.
BY STEPHEN MCNEIL, BRANZ BUILDING PHYSICIST
WUFI Plus evaluates the entire building performance using individual WUFI models.
WUFI IS A RANGE of computer models developed at the Fraunhofer Institute for Building Physics (FIBP). It stands for Wärme Und Feuchte Instationär and loosely translates to heat and moisture transiency. It was released to the public in 1995 and is an incredibly powerful tool for analysing the heat and moisture movement within buildings.
BRANZ solutions model local buildings
BRANZ has had a relationship with the Fraunhofer Institute since 2003 to mutu- ally develop WUFI, mainly focusing on the 2D version of the model. This work identified that the physics in the model was incomplete for the lightweight timber construction typical in New Zealand.
Air movement was identi ed as the key missing piece in the puzzle. BRANZ solved this by incorporating an air movement model in the 2D version of WUFI. This enabled groundbreaking work on frame drying and allowed air movement in 20 mm cavities to be modelled successfully.
52 — December 2015/January 2016 — Build 151
FEATURE SECTION