This is what was proposed. I know it was adopted but I haven't been able to confirm the final wording.

M1503.4 Makeup air required.
Kitchen exhaust systems capable of exhausting in excess of 400 cubic feet per minute (0.19 m3/s) shall be provided with makeup air at a rate approximately equal to the exhaust air rate. Such makeup air systems shall be equipped with not less than one motorized damper that shall be automatically controlled to operate simultaneously with the exhaust system.

Exception: Intentional openings for makeup air are not required for kitchen exhaust systems capable of exhausting not greater than 600 cubic feet per minute provided that one of the following conditions is met:
1. Where the floor area within the air barrier of a dwelling unit is at least 1500 square feet, and where natural draft or mechanical draft space-or water-heating appliances are not located within the air barrier.
2. Where the floor area within the air barrier of a dwelling unit is at least 3000 square feet, and where natural draft space-or water-heating appliances are not located within the air barrier.
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Reason: The language in 1503.4 is confusing and needs to be reworked. This proposal accomplishes the following. Detailed rationale follows the bullets.
1. Recognizes that makeup air (MUA) requirements are indifferent to the type of exhaust system (same MUA requirements should apply whether it’s a hood, down draft, through the wall vent, or any other type)
2. Clarifies where MUA comes from (transfer and outdoor air), and updates definitions to align with IMC
3. Clarifies what type of MUA system should be specified (at a minimum, one motorized, automatically controlled damper)
4. Provides an exception to relax the MUA requirements where the home is assumed to have sufficient natural infiltration to minimize the chance of backdrafting for the combustion appliances within the air barrier.

First, the current language only addresses exhaust hood systems, but the physics of back drafting are indifferent as to whether the exhaust system is a hood, a down draft, a through the wall vent, or any other type of exhaust system. So, the word “hood” is removed to reflect this fact.

Second, several definitions from the 2015 IMC are inserted clarify how the MUA system operates - things like where the MUA comes from, where the air must be introduced, etc. These definitions are also aligned with ASHRAE 62.

Third, this change clarifies the minimum required component of a MUA system (at least one motorized damper). A motorized damper is required because gravity dampers can malfunction at the low pressure differentials at which naturally vented appliances can potentially back draft (i.e., 3-5 Pascals based on info from BPI, CMHC, and CAN/CSA F326-M91; see references below). Malfunction can occur through improper balancing and slight restrictions in the damper caused by dirt, debris, or other matter.

Fourth, MUA should not be required where the home is deemed sufficiently leaky to minimize the chance of backdrafting for the combustion appliances within the air barrier. This exception assumes that mechanical draft combustion appliances can be operated safely to a pressure of -15 Pascals, and that direct vent appliances can be operated safely to a pressure of -50 Pascals. It also assumes that the home has a leakage of 3 ACH 50 and that there is good pressure distribution throughout the home. Ceiling height is assumed to be 8.5 ft. Equations used to estimate building leakage at the pressures of -15 Pa and -50 Pa were sourced from 2009 ASHRAE Fundamentals 16.15 (equations 41, 43 assuming a pressure exponent of 0.65).

References:
• BPI (Building Performance Institute). Technical Standards for the Building Analyst Professional. http://www.bpi.org/Web%20Download/BPI%20Standards/Building%20Analyst%20Professional_2-28-05nNC-newCO.pdf
• CAN/CSA F326-M91. Residential Mechanical Ventilation Systems, A National Standard of Canada. Reaffirmed 2010.
• CMHC (Canada Mortgage Housing Corporation). Chimney Safety Tests Users Manual, Second Edition. January 12, 1988. http://publications.gc.ca/collections/collection_2011/schl-cmhc/nh18-1/NH18-1-61-1988-eng.pdf.
• Minnesota Mechanical and Fuel Gas Code 1346.0501.501.3.2. https://www.revisor.mn.gov/rules/?id=1346.0501.
• 2009 ASHRAE Handbook of Fundamentals.

Cost Impact: This proposal has the potential to reduce the cost of construction by adding exceptions for MUA requirements when a dedicated MUA system is not needed.

Renovator8,

Thank you SO MUCH for providing this information. This is what I needed to know!

I don't think the change proposal was approved. See the link below.

If you are going to be responsible for important design decisions in a jurisdiction where the 2015 code applies (it is unusual for a new code to be adopted so soon and there are often amendments) you can ask the local building inspector or buy a copy of the code from ICCsafe.org for $150. It's cheap insurance.

Here is a link that might be useful: NAHB report

The link below will open the "Complete Revision History to the 2015 I-Codes" Look for Code Change No. RM34-13 on page 815 titled "Section 1503.4 Makeup Air Required".

Here is a link that might be useful: Complete Revision History to the 2015 I-Codes