Assemblies
An air barrier assembly
is a collection of air barrier materials and air barrier components
assembled together in a specific manner. A wall air barrier assembly
would include the main air barrier material and then use air barrier
components to join the air barrier materials together, to connect to
a window or door assembly, to connect to a roof assembly, to connect
to a foundation assembly and to connect to penetrations. The
performance of a air barrier assembly is far greater important that
the air permeance of the material.
The testing of an air
barrier assembly for air leakage is done in accordance with ASTM E
2357. The results will include the air permeance of the material
(the amount of air that passes through the material) the air
permeance of the components ((the amount of air that passes through
the material) and the air leakage that results from joining all the
pieces together. The air leakage of the air barrier assembly is not
to exceed 0.2L/(s•m2) @ 75Pa. (0.004 cfm/ft2
@ 1.57 psf)
For a manufacturer to
declare that they provide an air barrier assembly, the manufacturer
must determine what materials will be used, what components will be
used to join the materials together and how penetrations will be
dealt with. This is a major benefit to the design professional
issues such as compatibility is dealt with by the manufacturer
rather than the design professional using a trial and error method.
The issue of
installation is also dealt with in that the manufacturer must
declare the level of skill required to assembly the various
materials. When the assembly is put together for testing, the
installers will have the skill level required and declared by the
manufacturer. If there are no requirements – “anyone can do this”,
then that is the type of person used to assemble the specimen for
testing purposes. If the manufacturer sends his most qualified
engineers to assemble the test specimen, then they are declaring
that they must use people of this caliber to install their material
in the field. Most manufacturers declare that their installers have
to be trained in their installation instructions and prove that they
have the knowledge to install the materials properly by being
certified.
The test specimen is
configured as follows;
Specimen 1 - Opaque Wall
Specimen 2 - Continuity
at Penetrations
Foundation Interface and
Opaque Wall (with Modifications)
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