The Changing Requirements of Airtightness in the US for Commercial Buildings - The Airtightness of Mid and High-Rise Non-Residential Buildings

Concern over the airtightness of commercial buildings in North America goes back to the mid nineteen sixties, and with increasing concern in the mid-seventies, primarily due to the energy crisis, but also due to building performance, comfort and durability issues. The Model Canadian National Building Code was the first to adopt airtightness requirements for air barriers in 1985 and quantify it in 1995. In 2001 Massachusetts became the first state in the US to adopt a quantified airtightness requirement for air barrier materials and criteria for their design and construction in commercial and high-rise residential buildings. Many Standards and guides followed suit with airtightness requirements, including ASHRAE 90.1 2010 and IECC 2012, making airtightness mandatory in all commercial buildings built to those Standards and Codes. The US Army Corps of Engineers instituted airtightness testing requirements for all its new and renovated buildings in 2009. It requires that a whole building air leakage test be performed at completion of construction to verify performance of the constructed air barrier system. The Air Leakage Test Protocol for Building Envelopes was developed by the USACE Engineer Research and Development Center (ERDC) together with the Air Barrier Association of America (ABAA). In the meantime, ASHRAE decided that there was a lack of scientifically gathered and reported data on modern mid- and high-rise non-residential buildings built since the year 2000. It instituted a research study, 1478 RP, to measure and report air leakage rates for existing mid- and high-rise buildings, to develop a protocol for testing large buildings and to analyze the results with respect to design and construction parameters.