To limit the probability of openings in the joints of flexible sheet material (such as polyethylene) under in-service tensile stresses, which could lead to a loss of airtightness.
Where the air barrier system separates a garage, or suite containing a garage, from residential space, to limit the probability that gas and fumes will migrate from the garage into the remainder of the building, which could lead to the accumulation of gas and fumes and their subsequent ignition by a nearby ignition source, which could lead to a fire or explosion, which could lead to harm to persons.