Building Envelope Performance

Building failures remain significant despite recent advances in building technology and adopting performance-based building codes. The effect of incorporating innovative materials or systems in the moisture management potential of a building envelope component must be evaluated before use since the durability of the building might be compromised if these technologies lead to excessive moisture accumulation within the structure. The available analytical, numerical and laboratory experimental test cases used to assess the accuracy of these models are also based on simple geometry and boundary conditions to yield one- or two-dimensional HAM transfer processes. In reality, however, HAM transport is three-dimensional and involves complex airflows and convection loops in cavities, and thermal bridging at junctions such as at wall/roof, wall/window, wall/floor and other connection points. Our research focuses on investigating the long-term hygrothermal performance of building envelope components, via computer modeling and experimental study. Currently we are engaged in the following activities:

  • Further development of BSCE researcher’s 2D HAM building envelope model (HAMFit2D),
  • Experimental investigation of building envelope systems’ thermal and moisture performances.

 

Modeling: building envelope hygrothermal modeling
Modeling: building envelope hygrothermal modeling

BSCE uses its expertise and test facilities to investigate the already existing building performance, and conduct an innovative research to the design of new, state-of-the-art cladding systems.

The Centre uses computer models, experimental investigations and field monitoring to develop and study high performing building enclosures from energy efficiency, inhabitant  comfort and durability perspective.

Computer models

In addition to commercially available CFD and energy models, BSCE has developed several in house simulation models which predict the performance of the building envelope systems, whole building performance and human interactions to indoor climate.

Laboratory investigation

The building envelope material properties are studied using high end test equipment and test chambers available at the Centre.

The Hygrothermal property measurement laboratory is used to measure the thermal and moisture transport and storage of building envelope components. The laboratory measures hygrothermal properties of all types’ materials with its cutting edge test equipment. The laboratory provides a facility to measure properties including:

  • Material density;
  • Vapour permeability,
  • Isothermal sorption,
  • water uptake,
  • thermal conductivity
  • Air permeability

Our Lab possesses a rudimentary test chamber for air tightness and water penetration testing of window and wall assemblies. This facility have the flexibility to perform industry standard tests for quality assurance as well as special purpose tests of new building envelope practices.

BSCE is also developing an Environmental chamber multi-purpose test facility which will have a capacity to evaluate the performance of full-scale building envelope systems under controlled environmental conditions.

Field monitoring

Our Centre uses purpose-built test facilities to conduct filed monitoring of performance of building enclosure real-time against the outdoor climate.

BCIT’s Building Envelope Test Facility (BETF) is a unique research, development and demonstration resource created to evaluate the hygrothermal performance of full-scale building envelope assemblies and associated products under simulated indoor and real climatic outdoor conditions. It is the only known two-story facility of its kind located in the west coast rainforest environment.

The envelope evaluation at BETF involves:

  • Condition assessment
  • Infrared thermography
  • Envelope air-tightness
  • Blower door test

BSCE has developed a Whole Building Performance Research Laboratory (WBPRL) to conduct research on the dynamic interactions between building envelope components, the indoor environment and mechanical systems. The laboratory consists of two identical 250-square foot buildings that are fully exposed to natural environmental conditions. One of the buildings is used as a reference and the other one as a test building during the evaluation of alternative design options.

This test facility is a real time, real weather exposure facility for field tests on building envelope assemblies. It is valuable for research purposes as boundary conditions are realistic in magnitude, rate, sequence, and probability of occurrence.  BSCE holds a two-story test facility at BCIT’s Burnaby campus with a floor plan measuring 44′ by 28′. The test facility has the flexibility to accommodate wall panels of various sizes. It also has adjustable roof overhangs and the ability to test balconies and floor/wall junctions. The test facility is equipped to evaluate rain control efficiency and monitor the long-term hygrothermal performance of innovative envelope systems.

Preparation of test panel for field exposure experiment
Preparation of test panel for field exposure experiment