Combined Use of Inside and Outdoor Air (Condition 2)
NYC Mechanical Code § MC 705
in effectSection MC 705: Combined Use of Inside and Outdoor Air (Condition 2)
705.1 General.
This section shall apply only to appliances located in unconfined spaces in buildings of unusually tight construction. Combustion air supplied by a combined use of indoor and outdoor air shall be supplied through openings and ducts extending to the appliance room or to the vicinity of the appliance.
705.1.1 Openings and supply ducts.
Openings shall be provided, located and sized in accordance with Sections 702.3.1 and 702.3.2; additionally, there shall be one opening to the outdoors having a free area of at least 1 square inch per 5,000 Btu/h (440 mm2/kW) of total input of all appliances in the space.
Source: City of New York, Charter, Administrative Code and Rules (American Legal Publishing XML export, codelibrary.amlegal.com)URL: https://codelibrary.amlegal.com/codes/newyorkcity/latest/NYCadmin/0-0-0-194744Fetched: 10/24/2026
