2009 Mechanical Code Changes

The 2009 North Carolina Mechanical Code and 2009 North Carolina Fuel Gas Code became effective January 1, 2009, and become mandatory July 1, 2009. Until July 1, 2009, contractors may choose to use either the 2006 or the 2009 codes but may not mix the codes.

    PRIMARY CHANGES

1. Exhaust ducts for domestic clothes dryers shall be constructed of metal and shall have a smooth interior finish. With the exception of the transition duct, flexible ducts are prohibited. Where exhaust ducts are installed in concealed locations the developed length of the exhaust duct system shall be indicated by permanent labels or tags installed in an observable location.

Where the duct termination is less than 12 inches above finished grade, an areaway shall be provided with a cross-sectional area not less than 200 square feet. The bottom of the duct termination shall be no less than 12 inches above the areaway bottom.

2. On down-flow units and all other coils that do not have a secondary drain and do not have a means to install an auxiliary drain pan, a water-level monitoring device shall be installed inside the primary drain pan. This device shall shut off the equipment served in the event that the primary drain becomes restricted. Externally installed devices and devices installed in the drain line shall not be permitted.

3.  Ducts in the garage and ducts penetrating the walls or ceilings separating the dwelling from the garage shall be constructed of a minimum No. 26 gauge sheet steel or other approved material and shall have no openings into the garage.

4. Diffusers, registers and grilles shall be prohibited in the floor or its upward extension within toilet and bathing rooms required by the North Carolina Building Code to have smooth, hard, nonabsorbent surfaces.  Exception: Dwelling units

5. Insulation
    > Residential: Insulation. Supply and return ducts shall be insulated to a minimum of R-8. Ducts located in floor trusses shall be insulated to a minimum of R-6.

    > Commercial: All supply and return air ducts and plenums shall be insulated with a minimum of R-5 insulation when located in unconditioned spaces and with a minimum of R-8 insulation when located outside the building. When located within a building envelope assembly, the duct or plenum shall be separated from the building exterior or unconditioned or exempt spaces by a minimum of R-8 insulation.

6. Piping installed downstream of the point of delivery shall not extend through any townhouse other than the unit served by such piping.