INTERIOR ENVIRONMENT

SECTION 1201 — GENERAL

Buildings and portions thereof shall provide occupants with light and ventilation as set forth in this chapter. For ventilation of haz-ardous vapors or fumes, see Section 306.5 and the Mechanical Code.

SECTION 1202 — LIGHT AND VENTILATION IN GROUPS A, B, E, F, H, I, M AND S OCCUPANCIES 1202.1 Light. All enclosed portions of Groups A, B, E, F, H, I, M and S Occupancies customarily occupied by human beings shall be provided with natural light by means of exterior glazed open-ings with an area not less than one tenth of the total floor area, or shall be provided with artificial light. Such exterior openings shall open directly onto a public way or a yard or court as set forth in Section 1203.4. See Section 1003.2.9 for required means of egress illumination.

1202.2 Ventilation.

1202.2.1 General. All enclosed portions of Groups A, B, E, F, H, I, M and S Occupancies customarily occupied by human beings shall be provided with natural ventilation by means of openable exterior openings with an area not less than¹/20of the total floor area or shall be provided with a mechanically operated ventilation system. Such exterior openings shall open directly onto a public way or a yard or court as set forth in Section 1203.4. Such mechan-ically operated ventilation system shall be capable of supplying a minimum of 15 cubic feet per minute (7 L/s) of outside air per oc-cupant in all portions of the building during such time as the build-ing is occupied. If the velocity of the air at a register exceeds 10 feet per second (3 m/s), the register shall be placed more than 8 feet (2438 mm) above the floor directly beneath.

Toilet rooms shall be provided with a fully openable exterior window with an area not less than 3 square feet (0.279 m²), or a vertical duct not less than 100 square inches (64 516 mm²) in area for the first water closet plus 50 square inches (32 258 mm²) addi-tional of area for each addiaddi-tional water closet, or a mechanically operated exhaust system capable of providing a complete change of air every 15 minutes. Such mechanically operated exhaust sys-tems shall be connected directly to the outside, and the point of discharge shall be at least 3 feet (914 mm) from any opening that allows air entry into occupied portions of the building.

For ventilation of hazardous vapors or fumes in Group H Occu-pancies, see Sections 307.5.2 and 1202.2.3. For Group S, Division 3 Occupancies, see Section 1202.2.7.

1202.2.2 Groups B, F, M and S Occupancies. In all buildings classified as Groups B, F, M and S Occupancies or portions thereof where Class I, II or III-A liquids are used, a mechanically operated exhaust ventilation shall be provided sufficient to produce six air changes per hour. Such exhaust ventilation shall be taken from a point at or near the floor level.

1202.2.3 Group H Occupancies. Rooms, areas or spaces of Group H Occupancies in which explosive, corrosive, combus-tible, flammable or highly toxic dusts, mists, fumes, vapors or gases are or may be emitted due to the processing, use, handling or storage of materials shall be mechanically ventilated as required by the Fire Code and the Mechanical Code.

Ducts conveying explosives or flammable vapors, fumes or dusts shall extend directly to the exterior of the building without entering other spaces. Exhaust ducts shall not extend into or through ducts and plenums.

EXCEPTION: Ducts conveying vapor or fumes having flammable constituents less than 25 percent of their lower flammability limit may pass through other spaces.

Emissions generated at work stations shall be confined to the area in which they are generated as specified in the Fire Code and the Mechanical Code.

The location of supply and exhaust openings shall be in accord-ance with the Mechanical Code. Exhaust air contaminated by highly toxic material shall be treated in accordance with the Fire Code.

A manual shutoff control shall be provided outside of the room in a position adjacent to the access door to the room or in a location approved by the chief. The switch shall be of the break-glass type and shall be labeled VENTILATION SYSTEM EMERGENCY SHUTOFF.

1202.2.4 Group H, Division 4 Occupancies. In all buildings classified as Group H, Division 4 Occupancies used for the repair or handling of motor vehicles operating under their own power, mechanical ventilation shall be provided capable of exhausting a minimum of 1 cubic foot per minute per square foot (0.044 L/s/m²) of floor area. Each engine repair stall shall be equipped with an exhaust pipe extension duct, extending to the outside of the building, which, if over 10 feet (3048 mm) in length, shall me-chanically exhaust 300 cubic feet per minute (141.6 L/s). Con-necting offices and waiting rooms shall be supplied with conditioned air under positive pressure.

EXCEPTION: When approved, ventilating equipment may be omitted in repair garages, enclosed heliports and aircraft hangars when well-distributed unobstructed openings to the outer air of sufficient size to supply necessary ventilation are furnished.

1202.2.5 Group H, Division 6 Occupancies. In Group H, Divi-sion 6 Occupancies, mechanical exhaust ventilation shall be pro-vided throughout the fabrication area at the rate of not less than 1 cubic foot per minute per square foot (0.044 L/s/m²) of floor area. The exhaust air duct system of one fabrication area shall not connect to another duct system outside that fabrication area within the building.

Ventilation systems shall comply with the Mechanical Code ex-cept that the automatic shutoffs need not be installed on air-moving equipment. However, smoke detectors shall be installed in the circulating airstream and shall initiate a signal at the emer-gency control station.

Except for exhaust systems, at least one manually operated re-mote control switch that will shut down the fabrication area venti-lation system shall be installed at an approved location outside the fabrication area.

A ventilation system shall be provided to capture and exhaust fumes and vapors at work stations. Two or more operations shall not be connected to the same exhaust system when either one or the combination of the substances removed could constitute a fire, explosion or hazardous chemical reaction within the exhaust duct system.

Exhaust ducts penetrating occupancy separations shall be con-tained in a shaft of equivalent fire-resistive construction. Exhaust

FF FF FF FF F

COPYRIGHT 2003; International Conference of Building Officials Document provided by IHS Licensee=Aramco HQ/9980755100, User=, 12/31/2003 04:54:42 MST Questions or comments about this message: please call the Document

--````,```,,,,,,``,`,,,,,,`,-`-`,,`,,`,`,,`---1202.2.5

1205.1 1997 UNIFORM BUILDING CODE

1--136

ducts shall not penetrate area separation walls. Fire dampers shall not be installed in exhaust ducts.

1202.2.6 Group S repair and storage garages and aircraft hangars. In Group S, Division 3 repair garages and storage garages and in Division 5 aircraft hangars, the mechanical venti-lating system required by Section 1202.2.1 may be omitted when, in the opinion of the building official, the building is supplied with unobstructed openings to the outer air that are sufficient to provide the necessary ventilation.

1202.2.7 Group S parking garages. In Group S, Division 3 parking garages, other than open parking garages, used for storing or handling automobiles operating under their own power and on loading platforms in bus terminals, ventilation shall be provided capable of exhausting a minimum of 1.5 cubic feet per minute (cfm) per square foot (0.761 L/s/m²) of gross floor area. The build-ing official may approve an alternate ventilation system designed to exhaust a minimum of 14,000 cfm (6608 L/s) for each operating vehicle. Such system shall be based on the anticipated instanta-neous movement rate of vehicles, but not less than 2.5 percent (or one vehicle) of the garage capacity. Automatic carbon monoxide-sensing devices may be employed to modulate the ventilation sys-tem to maintain a maximum average concentration of carbon monoxide of 50 parts per million during any eight-hour period, with a maximum concentration not greater than 200 parts per mil-lion for a period not exceeding one hour. Connecting offices, wait-ing rooms, ticket booths and similar uses shall be supplied with conditioned air under positive pressure.

EXCEPTION: Mechanical ventilation need not be provided within a Group S, Division 3 parking garage when openings complying with Section 311.9.2.2 are provided.

SECTION 1203 — LIGHT AND VENTILATION IN GROUP R OCCUPANCIES

1203.1 General. For the purpose of determining the light or ven-tilation for Group R Occupancies required by this section, any room may be considered as a portion of an adjoining room when one half of the area of the common wall is open and unobstructed and provides an opening of not less than one tenth of the floor area of the interior room or 25 square feet (2.3 m²), whichever is greater.

Exterior openings for natural light or ventilation required by this section shall open directly onto a public way or a yard or court as set forth in Section 1203.4.

EXCEPTIONS: 1. Required exterior openings may open into a roofed porch where the porch:

1.1 Abuts a public way, yard or court;

1.2 Has a ceiling height of not less than 7 feet (2134 mm); and 1.3 Has a longer side at least 65 percent open and unobstructed.

2. Skylights.

1203.2 Light. Guest rooms and habitable rooms within a dwell-ing unit or congregate residence shall be provided with natural light by means of exterior glazed openings with an area not less than one tenth of the floor area of such rooms with a minimum of 10 square feet (0.93 m²).

EXCEPTION: Kitchens in Group R Occupancies may be pro-vided with artificial light.

1203.3 Ventilation. Guest rooms and habitable rooms within a dwelling unit or congregate residence shall be provided with natu-ral ventilation by means of openable exterior openings with an area of not less than¹/20of the floor area of such rooms with a minimum of 5 square feet (0.46 m²).

In lieu of required exterior openings for natural ventilation, a mechanical ventilating system may be provided. Such system shall be capable of providing two air changes per hour in guest rooms, dormitories, habitable rooms and in public corridors with a minimum of 15 cubic feet per minute (7 L/s) of outside air per occupant during such time as the building is occupied.

Bathrooms, water closet compartments, laundry rooms and similar rooms shall be provided with natural ventilation by means of openable exterior openings with an area not less than¹/20of the floor area of such rooms with a minimum of 1¹/2square feet (0.14 m²).

EXCEPTION: Laundry rooms in Group R, Division 3 Occupan-cies.

In lieu of required exterior openings for natural ventilation in bathrooms containing a bathtub, shower or combination thereof;

laundry rooms; and similar rooms, a mechanical ventilation sys-tem connected directly to the outside capable of providing five air changes per hour shall be provided. Such systems shall be con-nected directly to the outside, and the point of discharge shall be at least 3 feet (914 mm) from any opening that allows air entry into occupied portions of the building. Bathrooms that contain only a water closet, lavatory or combination thereof and similar rooms may be ventilated with an approved mechanical recirculating fan or similar device designed to remove odors from the air.

1203.4 Yards or Courts.

1203.4.1 General. This section shall apply to yards and courts adjacent to exterior openings that provide required natural light or ventilation. Such yards and courts shall be on the same property as the building.

1203.4.2 Yards. Yards shall not be less than 3 feet (914 mm) in width for one- and two-story buildings. For buildings more than two stories in height, the minimum width of the yard shall be in-creased at the rate of 1 foot (305 mm) for each additional story. For buildings exceeding 14 stories in height, the required width of the yard shall be computed on the basis of 14 stories.

1203.4.3 Courts. Courts shall not be less than 3 feet (914 mm) in width. Courts having windows opening on opposite sides shall not be less than 6 feet (1829 mm) in width. Courts bounded on three or more sides by the walls of the building shall not be less than 10 feet (3048 mm) in length unless bounded on one end by a public way or yard. For buildings more than two stories in height, the court shall be increased 1 foot (305 mm) in width and 2 feet (610 mm) in length for each additional story. For buildings exceeding 14 sto-ries in height, the required dimensions shall be computed on the basis of 14 stories.

Adequate access shall be provided to the bottom of all courts for cleaning purposes. Every court more than two stories in height shall be provided with a horizontal air intake at the bottom not less than 10 square feet (0.93 m²) in area and leading to the exterior of the building unless abutting a yard or public way. The construction of the air intake shall be as required for the court walls of the build-ing, but in no case shall be less than one-hour fire resistive.

SECTION 1204 — EAVES

Where eaves extend over required windows, they shall project no closer than 30 inches (762 mm) to any side or rear property line.