Interpretation #7086

Published October 24, 2012

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Original Request

Code Version
2010
Code
RESIDENT
Code Description
Residential
Chapter
1
Section
M1501.1
Topic
plastic exhaust grille

Question

Is it the intent of M1501.1 to prevent the installation of a plastic exhaust grille mounted outside onto the soffit to discharge bathroom exhaust? It prohibits "into" but duct is going "through" the soffit to the outside plastic grille.

Answer Published 10/24/2012 at 10:21 AM

The purpose of this section is to
prevent the exhaust from being
circulated back into the building
envelope. If the soffit is a solid
unvented type (no openings into the
attic within 3 feet to any side), then
an exhaust could be terminated through
the soffit with a sealed duct
connection and grille/louver.

Commentary

Restroom and dryer exhaust are listed as environmental air and therefore only require a 3 foot separation from any building openings or intake locations where the exhaust could be circulated back into the building envelope.