Michigan Administrative Code
Department - Licensing and Regulatory Affairs
Bureau of Construction Codes
Construction Code Commission General Rules
Construction Code
Part 9A - MECHANICAL CODE
AMENDMENTS AND ADDITIONS TO BASIC MECHANICAL CODE
Section R. 408.30945a - Ventilation; exhaust

Universal Citation: MI Admin Code R. 408.30945a

Current through Vol. 24-16, September 15, 2024

Rule 945a. Sections 501.3, 504.4, and 504.9.2, of the code are amended to read as follows:

501.3 Exhaust discharge. The air removed by every mechanical exhaust system shall be discharged outdoors at a point where it will not cause a public nuisance and not less than the distances specified in section 501.3.1 of the code. The air shall be discharged to a location from which it cannot again be readily drawn in by a ventilating system. Air shall not be exhausted into an attic or a crawl space, be directed onto walkways, or terminate within 3 feet of a ventilated section in a soffit.

Exceptions:

1. Whole-house ventilation-type attic fans shall be permitted to discharge into the attic space of dwelling units that have private attics.

2. Commercial cooking recirculating systems.

3. When installed in accordance with the manufacturer's instructions and when mechanical or natural ventilation is otherwise provided in accordance with chapter 4 of the code, listed and labeled domestic ductless range hoods shall not be required to discharge to the outdoors.

504.4 Exhaust installation. Dryer exhaust ducts for clothes dryers shall terminate on the outside of the building, shall not terminate within 3 feet of a ventilated section in a soffit, and shall be equipped with a back-draft damper. Screens shall not be installed at the duct termination. Ducts shall not be connected or installed with sheet metal screws or other fasteners that will obstruct the exhaust flow. Clothes dryer exhaust ducts shall not be connected to a vent connector, vent, or chimney. Clothes dryer exhaust ducts shall not extend into or pass through ducts or plenums.

504.9.2 Duct installation. Dryer exhaust ducts shall be supported at 4-foot, 1,219 millimeters, intervals and secured in place. The insert end of the duct shall extend into the adjoining duct or fitting in the direction of airflow. Ducts shall not be joined with screws or similar fasteners that protrude into the inside of the duct.

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