704.8 Allowable area of openings

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704.8 Allowable area of openings.

The maximum area of unprotected or protected openings permitted in an exterior wall in any story shall not exceed the values set forth in Table 704.8. Where both unprotected and protected openings are located in the exterior wall in any story, the total area of the openings shall comply with the following formula:

This equation is A = Actual area of protected openings, or the equivalent area of protected openings, Ae (see Section 704.7). Divided by a = Allowable area of protected openings. plus Au = Actual area of unprotected openings Divided by au = Allowable area of unprotected openings less than or equal to one.

(Equation 7-2)

where:

A = Actual area of protected openings, or the equivalent area of protected openings, A_e (see Section 704.7).

a = Allowable area of protected openings.

A_^u = Actual area of unprotected openings.

a_u = Allowable area of unprotected openings.

TABLE 704.8 MAXIMUM AREA OF EXTERIOR WALL OPENINGS^a

Classification of opening	FIRE SEPARATION DISTANCE (feet)
	0 to 3^e,h	Greater that 3 to 5^b	Greater than 5 to 10^d,f	Greater than 10 to 15^c,d,f	Greater than 15 to 20^c,f	Greater than 20 to 25^c,f	Greater than 25 to 30^c,f	Greater than 30
Unprotected	Not Permitted ^g	Not Permitted ^b,g	10%^g	15%^g	25%^g	45%^g	70%^g	No Limit
Protected	Not Permitted	15%	25%	45%	75%	No Limit	No Limit	No Limit

For SI: 1 foot = 304.8 mm.

a. Values given are percentage of the area of the exterior wall.

b. For occupancies in Group R-3, as applicable in Section 101.2, the maximum percentage of unprotected and protected exterior wall openings shall be 25 percent.

c. The area of openings in an open parking structure with a fire separation distance of greater than 10 feet shall not be limited.

d. For occupancies in Group H-2 or H-3, unprotected openings shall not be permitted for openings with a fire separation distance of 15 feet or less.

e. For requirements for fire walls for buildings with differing roof heights, see Section 705.6.1.

f. The area of unprotected and protected openings is not limited for occupancies in Group R-3, as applicable in Section 101.2, with a fire separation distance greater than 5 feet.

g. Buildings whose exterior bearing wall, exterior nonbearing wall and exterior structural frame are not required to be fire-resistance rated shall be permitted to have unlimited unprotected openings.

h. Includes accessory buildings to Group R-3 as applicable in Section 101.2.

704.8.1 Automatic sprinkler system.

In buildings equipped throughout with an automatic sprinkler system in accordance with Section 903.3.1.1, the maximum allowable area of unprotected openings in occupancies other than Groups H-1, H-2 and H-3 shall be the same as the tabulated limitations for protected openings.

704.8.2 First story.

In occupancies other than Group H, unlimited unprotected openings are permitted in the first story of exterior walls facing a street that have a fire separation distance of greater than 15 feet (4572 mm), or facing an unoccupied space. The unoccupied space shall be on the same lot or dedicated for public use, shall not be less than 30 feet (9144 mm) in width, and shall have access from a street by a posted fire lane in accordance with the International Fire Code.

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Excerpts from 2000 INTERNATIONAL BUILDING CODE®