Prof. Dr. Hartwig Künzel is the head of the Division of Hygrothermics at Fraunhofer Institut Bauphysik in Holzkirchen. It was an honour for us to host him here in New Zealand to discuss why and how we should increase the use of hygrothermal modelling in New Zealand.

During this event we discussed how we can use international best practice to simulate the risk of mould in our existing and proposed buildings. It was also an opportunity to meet Jesse Clarke, one of Australia’s leading WUFI® experts.

WUFI® Training

WUFI® training will be run at the pro clima HUB on February 26th – 28th and again June 26th-28th, 2019. See our Education page for details.

Training will consist of:

  • Day 1 – WUFI® Basics (1d): What is hygrothermal modelling and why do we need it? An introduction into the science and history of WUFI®
  • Days 1 & 2WUFI® User (1D): For people interested in modelling standard building elements.
  • Days 1 – 3WUFI® Advanced (2D): For modelling of complex forms such as wall-floor connections.

The History of WUFI®

WUFI® was created as a result of Hartwig Künzel’s PhD research at the Fraunhofer-Gesellschaft (Society) in Munich, Germany.

Founded in 1949, Fraunhofer-Gesellschaft consists of 66 separate institutes covering disciplines from life sciences through to information technology. The Society now employs around 25,000 staff across multiple disciplines. Hartwig’s work has been in the Fraunhofer Institute for Building Physics, IBP.

The Fraunhofer Institute for Building Physics, IBP is one of 66 Institutes that make up the Fraunhofer-Gesellschaft.
The Fraunhofer Institute for Building Physics, IBP is one of 66 Institutes that make up the Fraunhofer-Gesellschaft.

Hartwig began investigating the effects of adding insulation to heritage buildings. It became evident very quickly that adding insulation and increasing airtightness often induces moisture problems in buildings. Analysis of this problem shows that insulation moves the due point from outside, to inside the wall.

Adding insulation to a wall move the dew point.
Adding insulation to a wall move the dew point.

WUFI® was created to predict the accumulation and drying potential within a building element over time. The software uses dynamic modelling of both heat and moisture flows. With the correct climate data, internal conditions and material properties, WUFI® can be used to determine if a building element will get wet inside and for how long. From this, the risk of mould and deterioration can be determined.

Increasing the use of WUFI® in New Zealand

Jesse Clarke has been thinking about how to increase the update of hygrothermal modelling in Australia. The need for WUFI® modelling here in New Zealand is similar to the need in Australia. We’re increasing insulation levels and airtightness and we’ve already seen the consequences of leaky buildings. Hygrothermal analysis could help us avoid a second round of really expensive moisture-related mistakes.

To get the ball rolling though, we have a ‘chicken and egg’ problem as Jesse described it. Users need material property data from manufacturers, but manufacturers need to see a demand from users before investing in material testing to get the required property data.

Increasing uptake of WUFI® is a 'chicken and egg' problem.
Increasing uptake of WUFI® is a ‘chicken and egg’ problem.

Meanwhile, we also need to train more building industry professionals to become WUFI® users.

We’re working on the training. Register your interest here to become part of the solution.

For the material properties, Jesse proposes using the vast libraries of data that already exist for building materials that are very similar to what we have on on the market in Australia and New Zealand. There are, after all, only a finite number of ways to create fibreglass insulation or paper backed plasterboard. Using standard approximations of common building materials would be a great way to get started with WUFI® while we continue to campaign for more accurate, brand-specific material data.

We can use interpolation of existing data to approximate the most common building materials in Australia and New Zealand, says Jesse Clarke.
We can use interpolation of existing data to approximate the most common building materials in Australia and New Zealand, says Jesse Clarke.

 

Prof. Dr. Hartwig Künzel

Prof. Dr. Hartwig Künzel is the head of the Division of Hygrothermics at Fraunhofer Institut Bauphysik in Holzkirchen. It’s an honour for us to host him here in New Zealand and we hope you can join us to discuss why and how we should increase the use of hygrothermal modelling in New Zealand.

 

 

Jesse Clarke

Jesse Clarke joined Pro Clima with more than 15 years experience in the construction industry. He holds the technical lead role of the Building Science Manager, servicing Australia and New Zealand. Jesse is an active advocate for a holistic approach to the development of industry guidance, standards and codes. As the chairman of the AIRAH special technical group for building envelope physics is driving standardisation around the use of hygrothermal analysis (WUFI®) for healthier and more durable buildings.

Presentations

You can download a copy of the presentation slides (pdf versions) here:

Videos

Analysing the Risk of Moisture Accumulation and Mould in New Zealand Buildings Part 1 – Hartwig Künzel

Analysing the Risk of Moisture Accumulation and Mould in New Zealand Buildings Part 2 – Jesse Clarke

WUFI® Training

We will be hosting WUFI® training at the pro clima HUB in February and June 2019. See our Education page for details.

Further Information

Check out our WUFI® page for more links and information.