Materials, Components,
Assemblies & Systems
The term air barrier
needs to be better described. Many use the term when the actually
mean a material, a component, an assembly or a system. These terms
are defined as;
Air Barrier –
Primary material that prevents or reduces the passage of air through
the building enclosure system.
Air Barrier Material
– principal element installed to provide a continuous barrier to
the movement of air through building enclosures.
Air Barrier
Components – transitional element installed to provide a
continuous barrier to the movement of air through building
enclosures.
Air Barrier Assembly
- a collection of air barrier materials and air barrier
components installed to provide a continuous barrier to the movement
of air through building enclosures.
Air Barrier System
– a combination of air barrier assemblies installed to provide a
continuous barrier to the movement of air through building
enclosures.
The air permeance of any
air barrier material is 0.02L(s•m2) @ 75Pa. The
air permenance of drywall is equal to this and is used as a control
material. So any material that has a air permeance equal to or less
that this value qualifies as a air barrier material. As you look at
the materials used in a building you will find hundreds of materials
that meet this requirement.
Having air barrier
materials in a building does not provide you with a continuous plane
of air tightness. To achieve this you must join the various air
barrier materials together using air barrier components.
These components connect one material to another material, a
material to an assembly, and one assembly to another assembly. The
air permeance of an air barrier component is 0.02L(s•m2)
at 75 Pa.
An air barrier
assembly is simply a collection of air barrier materials
assembled together using air barrier components to provide a
continuous plane of air tightness for that assembly (i.e. wall
assembly). The maximum air leakage of an air barrier assembly should
be 0.2 L(s•m2) @ 75 Pa.
An air barrier system
is simply a collection of building assemblies lied together using
air barrier components to provide a continuous plane of air
tightness for the whole building enclosure. The air barrier system
determines the air leakage of the whole building. The maximum air
leakage of a whole building should be 2.0 L(s•m2) @ 75
Pa.
Back - Next
|
