Building Envelope Airtightness Quantification – Challenges applying sectional, sampling, or wall assembly testing methods
Wednesday May 8, 9:45am – 10:45am
Grand Ballroom
Currently there are standards (ASTM E-779, USACE Air Leakage Protocol) outlining the methodology and procedures to quantifying building envelope airtightness, using the building as a whole. However, there is currently no widely accepted standard that outlines the methodology and procedures that can be used to quantify building envelope airtightness using only a portion of the building (also known as sectional or sampling methods) Due to the lack of standards for this procedure and method, individual consultants / testers are having to come up with the variations of approaches, which are currently not standardized.
Sectional or sampling approaches can have inaccurate and widely misleading building envelope (BE) airtightness results due to unknown factors that are different for every building.
Most people using these approaches are not aware that there are different levels of uncontrolled or challenging conditions that are manipulating variables (different for every building) and can lead to reporting inaccurate airtightness results. Consultants/Testers can misinterpret and misrepresent the BE airtightness performance of a building. Builders can be misled of actual constructed BE airtightness performance, and be misguided that there are no deficiencies (if underestimated) or unrealistically too many issues to possibly fix (if overestimated).
There is no standard that verifies validity and repeatability of the data, where data measurements can be different every dataset, leading to high uncertainties and inaccuracies of the true building envelope airtightness.
Having collected empirical data from the testing of multiple towers, the results have the following variations, leading to invalidity and non-repeatable results.
Learning Objectives:
- Review and discuss metrics that help achieve validity and repeatability of building envelope airtightness results.
- Discuss theoretical assumptions and dynamic airflows within a building, leading to inaccuracies with sectional or sampling approaches, when attempting to measuring building envelope airtightness using only a portion of the building.
- Review and discuss airtightness data and results from various building / case studies
- Discuss research that has already been done, and discuss research left to be done before being able to standardize (if possible) a methodology, verify validity and repeatability of BE Airtightness testing using a portion of a building going forward
Stephen Wong, P.Eng.
Morrison Hershfield, Burnaby BC
Stephen Wong, P.Eng., is a Principal at Morrison Hershfield, Building Science Engineer, and Project Manager, specializing in high performance buildings. He has a wide range of experience with new construction design and field review, building component energy modeling, thermal performance analysis, and research projects driven to maximize building envelope performance. Stephen’s diverse experience involves residential, commercial, institutional, government, recreational, and mixed-use buildings. He is an industry leading specialist and Morrison Hershfield’s practice lead in overseeing the airtightness consulting practice, including testing, investigations, specifications, and computations to meet building envelope airtightness standards. Stephen has presented his research and investigations of building enclosures to international audiences.