Air Tightness of Commercial Buildings

[Guest guest]

For those that are interested....

The JBED (Journal of Building Enclosure Design) published by BETEC and NIBS came out with an entire publication devoted to airtight building assemblies. Lots of good stuff! One thing that sparked my interest was to know that the Brits are far ahead of the US with respect that their building codes now require an airtight building assembly in commercial buildings. Moreover, it is a performance criteria that the building is supposed to meet. For those of you that are into numbers, all commercial buildings greater than 10,000sqft must achieve an air tightness of 0.55cfm/building-sqft at a test pressure of 0.2inWG. (The Brits actual code is in metric units but I stated the criteria in US units for those of us that don’t have a good grasp of the metric system.) This is good stuff, i.e., performance criteria, to commission a building. And they are achieving these results at least 90% of the time. (I wonder how they “fix” a building that does not meet this criteria?). What’s more interesting is that 70% of the time, the buildings are achieving 50% better, or greater than 1.0cfm/sqft. Impressive!