Building Envelope Commissioning

Building envelope commissioning services include design review of building enclosure systems (walls, roofs, and foundations) to ensure the air tightness of the enclosure is below the prescribed maximum rates. Typically, 0.25 CFM per sq.ft. envelope surface, at a test pressure of 50 Pa, or in the case of DOD facilities, 0.25 CFM per sq.ft. envelope surface at a test pressure of 75 Pa.

As members of BCA (Building Commissioning Association), current maximum envelope leakage rates as recommended by ASHRAE in Standard 90.1 - 2007 Energy Efficient Design of New Buildings Except Low Rise Residential Buildings, the State of Massachusetts, and Canadian government, our design review, as part of the building enclosure commissioning services or as an independent review not associated with building enclosure commissioning, entails tracing the building enclosure to identify penetrations and changes in components and the continuity of the air barrier. Our review also includes the available details that indicate air sealing. During the construction phase, we observe the installation of air barrier, vapor barrier, and water diversion components (flashing, etc.). Testing of wall sections early in the construction process must be provided in order to verify the leakage rate of the wall and roof systems (walls, openings, penetrations, joint, corners, etc.)

Figure 1: Wall commissioning transition strips at windows and joints and sheathing of bump cut.

Figure 2: Blower doors being used to generate guarded pressure zones which are used to isolate the test zone floor below from the remainder of the facility to allow measurement of the wall leakage through the test zone.