Section 508 Incidental Use Areas and Mixed Occupancies

Where a building or portion thereof contains two or more occupancies or uses, the building or portion thereof shall comply with the applicable provisions of this section. For additional requirements for mixed occupancies, see Section 506.4.1.

Incidental use areas shall comply with the provisions of this section.

A space that is listed in Table 508.2 and is incidental to a main occupancy shall be considered an incidental use area. An incidental use area shall be classified in accordance with the main occupancy to which the use is incidental; or such area shall be classified in accordance with its actual occupancy and shall comply with Section 508.3 for mixed occupancies.

TABLE 508.2
INCIDENTAL USE AREAS

ROOM OR AREA	SEPARATIONa
Furnace room where any piece of equipment is over 400,000 Btu per hour input	2 hour; or 1 hour and provide automatic fire-extinguishing system
Furnace room where any piece of equipment is 400,000 Btu per hour input or less, except in R-3 occupancy	1 hour or provide automatic sprinkler systemb
Rooms with any boiler over 15 psi and 10 horsepower	2 hour; or 1 hour and provide automatic fire-extinguishing system
Rooms with any boiler 15 psi or less and 10 horsepower or less, except in R-3 occupancy	1 hour or provide automatic sprinkler system
Mechanical and/or electrical equipment room, except in R-3 occupancy	1 hour or provide automatic sprinkler system
Refrigerant machinery rooms	1 hour or provide automatic sprinkler system
Parking garage (Section 406.2)	2 hours; or 1 hour and provide automatic fire-extinguishing system
Hydrogen cut-off rooms	2-hour fire barriers and floor/ceiling assemblies in all occupancy groups
Incinerator rooms	2 hours and automatic sprinkler system
Paint shops, not classified as Group H, located in occupancies other than Group F	2 hours; or 1 hour and provide automatic fire-extinguishing system
Laboratories and vocational shops, not classified as Group H, located in Group E or I-2 occupancies	2 hour; or 1 hour and provide automatic fire-extinguishing system
Laundry rooms over 100 square feet, except within dwelling units	1 hour or provide automatic fire-extinguishing system
Storage rooms over 100 square feet, except in R-3 occupancy	1 hour or provide automatic fire-extinguishing system
Group I-3 cells equipped with padded surfaces	1 hour
Group I-2 waste and linen collection rooms	1 hour
Waste and linen collection rooms over 100 square feet	1 hour or provide automatic fire-extinguishing system
Stationary lead-acid battery systems having a liquid capacity of more than 100 gallons used for facility emergency power or uninterrupted power supplies	2-hour fire barriers and floor/ceiling assemblies in all occupancy groups
Rooms utilizing the electrical installation standards for "information technology rooms" as per Section 645.1 of the New York City Electrical Code	As may be required by the New York City Electrical Code

Any additional fire protection requirements in Chapter 9 for an incidental use area shall be based upon the occupancy classification of the area's main occupancy.

The actual floor area of an incidental use area shall be treated as being in the same occupancy group as its main occupancy for the purposes of calculating allowable height and area in accordance with Section 503.1.

Incidental use areas shall be separated or protected, or both, from all other occupancies in accordance with Table 508.2.

Where Table 508.2 requires a fire-resistance-rated separation, the incidental use area shall be separated from the remainder of the building by a fire barrier constructed in accordance with Section 706 or a horizontal assembly constructed in accordance with Section 711, or both. Where Table 508.2 permits an automatic fire-extinguishing system without a fire barrier, the incidental use area shall be separated from the remainder of the building by construction capable of resisting the passage of smoke. The partitions shall extend from the floor to the underside of the fire-resistance-rated floor/ceiling assembly or fire-resistance-rated roof/ceiling assembly above or to the underside of the floor or roof sheathing, or sub deck above. Doors shall be self- or automatic closing upon detection of smoke in accordance with Section 715.4.7.3. Doors shall not have air transfer openings and shall not be undercut in excess of the clearance permitted in accordance with NFPA 80.

Each portion of a building shall be individually classified in accordance with Section 302.1. Where a building contains more than one occupancy group, the building or portion thereof shall comply with Sections 508.3.1, 508.3.2, 508.3.3 or a combination of these sections.

Accessory occupancies are those occupancies subsidiary to the main occupancy of the building or portion thereof. In addition, the aggregate of all accessory occupancies located on a single story shall not occupy more than 10 percent of the floor area of the story in which they are located and shall not exceed the tabular values in Table 503 for each such accessory occupancy, without height and area increases in accordance with Sections 504 and 506 for such accessory occupancies.

Each accessory occupancy shall be individually classified in accordance with Section 302.1. All code requirements shall apply to each accessory occupancy based upon its individual occupancy classification, except that the most restrictive applicable provisions of Section 403 and Chapter 9 shall apply to the entire building or portion thereof.

The allowable height and area of the building shall be based on the allowable height and area for the main occupancy in accordance with Section 503.1. The height and area of any accessory occupancy shall not exceed the tabular values in Table 503, without height and area increases in accordance with Sections 504 and 506 for such accessory occupancies.

No separation is required between an accessory occupancy and its main occupancy.

Buildings or portions of buildings that comply with the provisions of this section shall qualify as nonseparated occupancies.

Nonseparated occupancies shall be individually classified in accordance with Section 302.1. All code requirements shall apply to each portion of the building based on the occupancy classification of that space, except that the most restrictive applicable provisions of Section 403 and Chapter 9 shall apply to the entire building or portion thereof.

The allowable height and area of the building or portion thereof shall be based on the most restrictive allowances for the occupancy groups under consideration for the type of construction of the building in accordance with Section 503.1.

No separation is required between occupancies.

Buildings or portions of buildings that comply with the provisions of this section shall qualify as separated occupancies.

Separated occupancies shall be individually classified in accordance with Section 302.1. Each fire area shall comply with this code based on the occupancy classification of that portion of the building.

In each story, the building area shall be such that the sum of the ratios of the actual floor area of each occupancy divided by the allowable area of each occupancy shall not exceed one.

Each occupancy shall comply with the height limitations based on the type of construction of the building in accordance with Section 503.1. The height, in both feet and stories, of each fire area shall be measured from grade plane. This measurement shall include the height, in both feet and stories, of intervening fire areas.

Individual occupancies shall be separated from adjacent occupancies in accordance with Table 508.3.3. Where the building is equipped throughout with an automatic sprinkler system, installed in accordance with Section 903.3.1.1, the fire-resistance ratings in Table 508.3.3 are permitted to be reduced by 1 hour, but in no case shall be less than that required for floor construction according to the type of construction, or less than 1 hour, whichever is higher.

Required separations shall be fire barriers constructed in accordance with Section 706 or horizontal assemblies constructed in accordance with Section 711, or both, so as to completely separate adjacent occupancies.