Page 48 - 2018_IMC

CHAPTER 4

VENTILATION

User note:
About this chapter: Chapter 4 intends to provide an indoor atmosphere that protects the health and well-being of building occupants. Both
mechanical and natural ventilation are addressed. Mechanical ventilation provides what is considered to be acceptable indoor air quality.
Mechanical ventilation minimizes adverse health effects and provides an atmosphere that generally is not objectionable to occupants.

SECTION 401 1612 of the International Building Code for utilities
GENERAL and attendant equipment.
401.1 Scope. This chapter shall govern the ventilation of 401.5 Intake opening protection. Air intake openings that
spaces within a building intended to be occupied. Mechanical terminate outdoors shall be protected with corrosion-resistant
exhaust systems, including exhaust systems serving clothes screens, louvers or grilles. Openings in louvers, grilles and
dryers and cooking appliances; hazardous exhaust systems; screens shall be sized in accordance with Table 401.5, and
dust, stock and refuse conveyor systems; subslab soil exhaust shall be protected against local weather conditions. Louvers
systems; smoke control systems; energy recovery ventilation that protect air intake openings in structures located in hurri-
systems and other systems specified in Section 502 shall cane-prone regions, as defined in the International Building
comply with Chapter 5. Code, shall comply with AMCA 550. Outdoor air intake
401.2 Ventilation required. Every occupied space shall be openings located in exterior walls shall meet the provisions
ventilated by natural means in accordance with Section 402 for exterior wall opening protectives in accordance with the
or by mechanical means in accordance with Section 403. International Building Code.
Where the air infiltration rate in a dwelling unit is less than 5 TABLE 401.5
air changes per hour when tested with a blower door at a pres- OPENING SIZES IN LOUVERS, GRILLES
sure of 0.2-inch water column (50 Pa) in accordance with AND SCREENS PROTECTING AIR INTAKE OPENINGS
Section R402.4.1.2 of the International Energy Conservation MINIMUM AND MAXIMUM
Code, the dwelling unit shall be ventilated by mechanical OUTDOOR OPENING TYPE OPENING SIZES IN LOUVERS,
a
GRILLES AND SCREENS
means in accordance with Section 403. Ambulatory care Intake openings in
1
1
facilities and Group I-2 occupancies shall be ventilated by residential occupancies Not < / inch and not > / inch
4
2
mechanical means in accordance with Section 407.
Intake openings in other 1
401.3 When required. Ventilation shall be provided during than residential occupancies > / inch and not > 1 inch
4
the periods that the room or space is occupied.
For SI: 1 inch = 25.4 mm.
401.4 Intake opening location. Air intake openings shall a. For rectangular openings, the table requirements apply to the shortest side.
comply with all of the following: For round openings, the table requirements apply to the diameter. For
1. Intake openings shall be located not less than 10 feet square openings, the table requirements apply to any side.
(3048 mm) from lot lines or buildings on the same lot. 401.6 Contaminant sources. Stationary local sources pro-
ducing airborne particulates, heat, odors, fumes, spray,
2. Mechanical and gravity outdoor air intake openings
shall be located not less than 10 feet (3048 mm) hori- vapors, smoke or gases in such quantities as to be irritating or
zontally from any hazardous or noxious contaminant injurious to health shall be provided with an exhaust system
source, such as vents, streets, alleys, parking lots and in accordance with Chapter 5 or a means of collection and
loading docks, except as specified in Item 3 or Section removal of the contaminants. Such exhaust shall discharge
501.3.1. Outdoor air intake openings shall be permitted directly to an approved location at the exterior of the build-
to be located less than 10 feet (3048 mm) horizontally ing.
from streets, alleys, parking lots and loading docks pro-
vided that the openings are located not less than 25 feet
(7620 mm) vertically above such locations. Where SECTION 402
openings front on a street or public way, the distance NATURAL VENTILATION
shall be measured from the closest edge of the street or [BG] 402.1 Natural ventilation. Natural ventilation of an
public way. occupied space shall be through windows, doors, louvers or
3. Intake openings shall be located not less than 3 feet other openings to the outdoors. The operating mechanism for
(914 mm) below contaminant sources where such such openings shall be provided with ready access so that the
sources are located within 10 feet (3048 mm) of the openings are readily controllable by the building occupants.
opening. [BG] 402.2 Ventilation area required. The minimum open-
4. Intake openings on structures in flood hazard areas able area to the outdoors shall be 4 percent of the floor area
shall be at or above the elevation required by Section being ventilated.

2018 INTERNATIONAL MECHANICAL CODE  31
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