Statutes, codes, and regulations
District Of Columbia Administrative Code
Title 12 - CONSTRUCTION CODES SUPPLEMENT OF 2017Subtitle 12-E - MECHANICAL CODE SUPPLEMENT OF 2017
Chapter 12-E4 - VENTILATION
Rule 12-E401 - GENERAL

D.C. Mun. Regs. tit. 12, r. 12-E401

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Current through Register Vol. 71, No. 49, December 6, 2024
Rule 12-E401 - GENERAL

Strike Section 401.2 of the International Mechanical Code in its entirety and insert new Section 401.2 in its place in the Mechanical Code to read as follows.

401.2

Ventilation required. Every occupied space shall be ventilated by natural means in accordance with Section 402 or by mechanical means in accordance with Section 403.

1. Each new dwelling unit shall be ventilated by mechanical means in accordance with Section 403 and shall have at least one opening to the outdoors for natural ventilation. The minimum openable area to the outdoors shall be 4 percent of the floor area of the habitable spaces.
2. Where an existing dwelling unit is undergoing a Level 3 alteration and its air infiltration rate is less than five (5) air changes per hour when tested with a blower door at a pressure of 0.2 inch water column (50 Pa) in accordance with Section R402.4.1.2 of the Energy Conservation Code, the dwelling unit shall be ventilated by mechanical means in accordance with Section 403.
3. Ambulatory care facilities and Group I-2 occupancies shall be ventilated by mechanical means in accordance with Section 407.

Strike Section 401.4 of the International Mechanical Code in its entirety and insert a new Section 401.4 into the Mechanical Code in its place to read as follows:

401.4

Intake opening location. Air intake openings shall comply with all of the following:

1. Intake openings shall be located a minimum of 10 feet (3048 mm) from lot lines or buildings on the same lot. On narrow lots where a 10-foot distance from lot lines cannot be achieved, the code official is authorized to approve a shorter distance.
2. Mechanical and gravity outdoor air intake openings shall be located not less than 10 feet (3048 mm) horizontally from any hazardous or noxious contaminant source, such as vents, streets, alleys, parking lots and loading docks, except as specified in item 3 or Section 501.3.1. Outdoor air intake openings shall be permitted to be located less than 10 feet (3048 mm) horizontally from areas with vehicular access, such as streets, alleys, parking lots and loading docks, provided that the openings are located not less than 25 feet (7620 mm) vertically above the surface of those areas. Where openings front on a street or public way, the distance shall be measured from the closest edge of the roadway portion of the street or public way.
3. Intake openings shall be located not less than 3 feet (914 mm) below contaminant sources where such sources are located within 10 feet (3048 mm) of the opening.
4. Intake openings on structures in flood hazard areas shall be at or above the elevation required by Section 1612 of the International Building Code for utilities and attendant equipment.
5. The bottom of outdoor air intake openings shall be not less than 2 feet (610 mm) above the adjacent grade or adjacent roof, or above the bottom of areaways.

D.C. Mun. Regs. tit. 12, r. 12-E401

Final Rulemaking published at 67 DCR 5679 (5/29/2020); amended by Final Rulemaking published at 68 DCR 007412 (7/30/2021)