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Unique new "weather machine" studies wall performance

IRC's Building Envelope and Structure Program has a new test facility that can monitor and weigh a full-scale wall assembly (2.4 m x 2.4 m), providing useful information about how walls dry out.

The climatic chamber, which is unique in North America, is known as the Envelope Environmental Exposure Facility (EEEF). It can simulate interior and exterior climatic conditions over extended periods of time, controlling both temperatures (ranging from -47 to +48°C) on the 'weather' side of the wall and humidity levels (ranging from 10 to 100% RH).

IRC RESEARCHERS PREPARE FULL-SCALE WALL SPECIMEN FOR A DRYING EXPERIMENT IN THE ENVELOPE ENVIRONMENTAL EXPOSURE FACILITY (EEEF)
IRC RESEARCHERS PREPARE FULL-SCALE WALL SPECIMEN FOR A DRYING EXPERIMENT IN THE ENVELOPE ENVIRONMENTAL EXPOSURE FACILITY (EEEF)

Researchers, in conjunction with key industry partners, are using the facility to benchmark the thermal and moisture performance of walls in various climates, and to study drying behaviour at the interfaces between walls and a) other building elements (such as windows) and b) service penetrations.

Already they have gathered key information about the drying rate of wood-frame wall components, which they are using to confirm the drying characteristics of the wall assembly predicted by a combined heat, air and moisture transfer model, hygIRC. These comparisons between experimental results and model predictions have provided insight into how water re-distributes itself within the wall before drying out.

SCHEMATIC OF THE EEEF'S WALL-WEIGHING SYSTEM
SCHEMATIC OF THE EEEF'S WALL-WEIGHING SYSTEM

The facility features several innovations:

  • a weighing system that detects water evaporating from the wall by measuring the total wall weight with great precision (in grams) and tracking this weight over time;
  • a frame and gasket technique for sealing the wall specimens to the enclosure, without interfering with the weighing process;
  • state-of-the-art moisture meters for mapping differential drying on the face of the wall;
  • a complete data acquisition package to control and monitor experiments, and a comprehensive data analysis technique for interpreting the results.

The next stage of development for this facility will integrate the effects of rain, wind and some aspects of solar radiation.

Specific questions can be directed to Dr. Wahid Maref at (613) 993-5709, fax (613) 998-6802, or e-mail wahid.maref@nrc-cnrc.gc.ca.

 

IRC researchers and their industry partners are using the Envelope Environmental Exposure Facility in the MEWS Project (Moisture Management for Exterior Wall Systems). The project objective is to develop effective moisture control strategies for walls in various climates.

The project partners are:

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