FAQ

Historically designers and engineers have not detailed the point where the HVAC
refrigerant pipes penetrate the exterior wall, resulting in the use of makeshi methods
that are guaranteed to fail. Expansion and contraction can cause cracking and separation,
leading to water damage, mold, rot, structural damage, air leakage, energy loss, poor
indoor air quality and rodent intrusion. Many of these makeshi methods are very
unprofessional, look sloppy, and can become a source of frustration for building owners,
contractors, designers and engineers.
Without a detail to follow, installers oen turn to unsustainable materials such as putty,
silicone and expanding foam to seal these penetrations. Caulking stiens, dries up,
cracks and disconnects from surfaces. Acrylic caulk is durable but shrinks over time.
Gasket sealing is the preferred method for sustainable pipe penetration sealing.
Architects specifying penetrations of the air barrier envelope for Division 7 Thermal and
Moisture Protection oen use the same sealing methods for roof and wall flashings,
utilizing either a large opening or a thin washer to seal all pipe penetrations. However,
unlike other pipes, refrigerant piping usually includes two pipes: the suction pipe and
the liquid pipe. These two pipes can tear apart thin washers and cause air leakage
and water penetration. When flashings with a large-diameter opening are sealed with
an expanding foam, the friction from the vibration of the refrigerant piping can turn
expanding foam into powder.
The architect and engineering specification writer should take great care not to specify
the same flashing or sealing methods for refrigerant piping as they would with other
pipe penetrations.
Why are HVAC pipe wall
penetration seals failing?
Seal failures for HVAC pipe penetrations continue to be a problem for the construction
industry. Concerns including structural damage, energy loss and air leakage from building
envelopes necessitate specifying a professionally engineered sealing system such as the
Airex Pro System Kit™ for exterior wall penetrations. The Airex Pro System Kit™ will ensure
installations meet all energy, mechanical and building code requirements, protecting
the building’s airtight envelope, your clients and your reputation.
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FAQ
Failure of HVAC Penetrations