The US Army Corps of Engineers is raising requirements with a directive for air barrier performance and building air tightness testing requirements for all new and renovation construction projects starting in 2010.
Under the directive released October 2009, completed buildings must be tested and must demonstrate that the air leakage rate of the building envelope does not exceed 0.25CFM/sq ft at a pressure differential of 0.3 iwg (75 Pa) in accordance with ASTM E 779 or ASTM E 1827. Testing must be performed using both pressurization and depressurization.
"The Army Corps really leads in whole building performance initiatives," says Laverne Dalgleish, Principal of Building Professionals Consortium and Executive Director of the Air Barrier Association of America (ABAA). "They have already established a protocol for blower door testing for air tightness of the building envelope in large buildings, but now we will be working with them to take it to the next level and develop that protocol into a new ASTM Standard in subcommittee E06.41 which will complement the existing ASTM E 779."
Establishing a new standard allows for the language within it to be adopted into building codes as mandatory elements, instead of guidelines.
"We're working hard to have the drafts ready for review in the next few months," says Dalgleish. "That means states can incorporate the new language into their next code cycle. The important thing here is that we're going beyond just putting air barrier materials into a building. We'll have to test to make sure they are performing properly as an installed air barrier assembly. Quality workmanship will be recognized and others will have to improve their skills to keep up with the industry."
The Army Corps of Engineers already uses ABAA accredited contractors for air barrier installations on some of its projects. Discussions are underway to have all of its projects completed under the ABAA Quality Assurance Program. Recognizing the need for technology transfer and a trained and skilled workforce to operate under the new standard, the two organizations are working on a parallel project to establish three specific personnel certifications for individuals conducting the air tightness testing and ensuring the required performance levels are achieved.
According to Dalgleish, the first certification will recognize individuals with the knowledge required to oversee the testing process. The second certification will recognize individuals with the abilities required to actually conduct the testing in the field. The third certification will recognize individuals with the knowledge and skills required to rectify performance problems identified during the testing process and reduce air leakage rates to acceptable levels.
"A lot of the techniques that will be used to correct those performance problems are the same as the ones we see being implemented to reduce air leakage in existing buildings," says Dalgleish. "When we consider that 85 percent of the buildings that will exist in the year 2020 have already been built, this is a skill set that will be in increasing demand in the future."
To review and download Army Corps of Engineers air barrier standards and protocols, visit the Whole Building Design Guide.