SECTION 704
EXTERIOR WALLS
704.1 General.
Exterior walls shall be fire-resistance rated and have opening protection as required by this section.
704.2 Projections.
Cornices, eave overhangs, exterior balconies and similar architectural appendages extending beyond the floor area shall conform to the requirements of this section or Section 1406. Exterior egress balconies and exterior exit stair- ways shall also comply with Sections 1004.3.3 and 1005.3.6. Projections shall not extend beyond the distance determined by the following two methods, whichever results in the lesser projection:
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A point one-third the distance to the property line from an assumed vertical plane located where protected openings are required in accordance with Section 704.8.2. More than 12 inches (305 mm) into areas where openings are prohibited.
704.2.1 Types I and II construction.
Projections from walls of Type I or II construction shall be of noncombustible materials or combustible materials as allowed by Sections 1406.3 and 1406.4.
704.2.2 Types III, IV and V construction.
Projections from walls of Type III, IV or V construction shall be of any approved material.
704.2.3 Combustible projections.
Combustible projections located where openings are not permitted or where protection of openings is required shall be of at least 1-hour fire-resistance-rated construction, Type IV construction or as required by Section 1406.3.
Exception: Type V construction shall be allowed for R-3 occupancies, as applicable in Section 101.2.
704.3 Buildings on the same property and buildings containing courts.
For the purposes of determining the required wall and opening protection and roof-covering requirements, buildings on the same property and court walls of buildings over one story in height shall be assumed to have a property line between them.
Exception: In court walls where opening protection is required, such protection is not required provided:
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Not more than two levels open into the court;
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The aggregate area of the building, including the court, is within the allowable area; and
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The building is not classified as Group I.
Where a new building is to be erected on the same property as an existing building, the location of the assumed property line with relation to the existing building shall be such that the exterior wall and opening protection of the existing building meet the criteria as set forth in Sections 704.5 and 704.8.
Exception: Two or more buildings on the same property shall either be regulated as separate buildings or shall be considered as portions of one building if the aggregate area of such buildings is within the limits specified in Chapter 5 for a single building. Where the buildings contain different occupancy groups or are of different types of construction, the area shall be that allowed for the most restrictive occupancy or construction.
704.4 Materials.
Exterior walls shall be of materials permitted by the building type of construction.
704.5 Fire-resistance rating.
Exterior walls shall be fire-resistance rated in accordance with Tables 601 and 602. The fire-resistance rating of exterior walls with a fire separation distance of greater than 5 feet (1524 mm) shall be rated for exposure to fire from the inside. The fire-resistance rating of exterior walls with a fire separation distance of 5 feet (1524 mm) or less shall be rated for exposure to fire from both sides.
704.6 Structural stability.
The wall shall extend to the height required by Section 704.11 and shall have sufficient structural stability such that it will remain in place for the duration of time indicated by the required fire-resistance rating.
704.7 Unexposed surface temperature.
Where protected openings are not limited by Section 704.8, the limitation on the rise of temperature on the unexposed surface of exterior walls the exterior wall in any story, the total area of the openings shall comply with the following formula:
Ae = A + (Af X Feo)
(Equation 7-1)
where:
Ae = Equivalent area of protected openings.
A = Actual area of protected openings.
Af = Area of exterior wall surface in the story under consideration exclusive of openings, on which the temperature limitations of ASTM E 119 for walls are exceeded.
Feo = An "equivalent opening factor" derived from Figure 704.7 base on average temperature of the unexposed wall surface and the fire-resistance rating of the wall.
FIGURE 704.7
EQUIVALENT OPENING FACTOR
For SI: 0C = [(0F) - 32] /1.8
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:
(Equation 7-2)
where:
A = Actual area of protected openings, or the equivalent area of protected openings, Ae (see Section 704.7).
a = Allowable area of protected openings.
Au = Actual area of unprotected openings.
au = Allowable area of unprotected openings.
TABLE 704.8 MAXIMUM AREA OF EXTERIOR WALL OPENINGSa
| Classification of opening | FIRE SEPARATION DISTANCE (feet) | |||||||
| 0 to 3 e,h | Greater that 3 to 5b | Greater than 5 to 10d,f | Greater than 10 to 15c,d,f | Greater than 15 to 20c,f | Greater than 20 to 25c,f | Greater than 25 to 30c,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.
704.9 Vertical separation of openings.
Openings in exterior walls in adjacent stories shall be separated vertically to protect against fire spread on the exterior of the buildings where the openings are within 5 feet (1524 mm) of each other horizontally and the opening in the lower story is not a protected opening in accordance with Section 714.3.7. Such openings shall be separated vertically at least 3 feet (914 mm) by spandrel girders, exterior walls or other similar assemblies that have a fire resistance rating of at least 1 hour or by flame barriers that extend horizontally at least 30 inches (762 mm) beyond the exterior wall. Flame barriers shall also have a fire-resistance rating of at least 1 hour. The unexposed surface temperature limitations specified in ASTM E 119 shall not apply to the flame barriers or vertical separation unless otherwise required by the provisions of this code.
Exceptions:
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This section shall not apply to buildings that are three stories or less in height.
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This section shall not apply to buildings equipped throughout with an automatic sprinkler system in accordance with Section 903.3.1.1.
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Open parking garages.
704.10 Vertical exposure.
For buildings on the same lot, approved protectives shall be provided in every opening that is less than 15 feet (4572 mm) vertically above the roof of an adjoining building or adjacent structure that is within a horizontal fire separation distance of 15 feet (4572 mm) of the wall in which the opening is located.
Exception: Opening protectives are not required where the roof construction has a fire-resistance rating of not less than 1 hour for a minimum distance of 10 feet (3048 mm) from the adjoining building and the entire length and span of the supporting elements for the fire-resistance-rated roof assembly has a fire-resistance rating of not less than 1 hour.
704.11 Parapets.
Parapets shall be provided on exterior walls of buildings.
Exception: A parapet need not be provided on an exterior wall where any of the following conditions exist:
1. The wall is not required to be fire-resistance rated in accordance with Table 602 because of fire separation distance.
2. The building has an area of not more than 1,000 square feet (93 m2) on any floor.
3. Walls that terminate at roofs of not less than 2-hour fire-resistance-rated construction or where the roof, including the deck and supporting construction, is constructed entirely of noncombustible materials.
4. One-hour fire-resistance-rated exterior walls that terminate at the underside of the roof sheathing, deck or slab, provided:
4.1. Where the roof/ceiling framing elements are parallel to the walls, such framing and elements supporting such framing shall not be of less than 1-hour fire-resistance-rated construction for a width of 4 feet (1220 mm) measured from the interior side of the wall for Groups R and U and 10 feet (3048 mm) for other occupancies.
4.2. Where roof/ceiling framing elements are not parallel to the wall, the entire span of such framing and elements supporting such framing shall not be of less than 1-hour fire-resistance-rated construction.
4.3. Openings in the roof shall not be located within 5 feet (1524 mm) of the 1-hour fire-resistance-rated exterior wall for Groups R and U and 10 feet (3048 mm) for other occupancies.
4.4. The entire building shall be provided with not less than a Class B roof covering.
5. In occupancies of Groups R-2 and R-3 as applicable in Section 101.2, both provided with a Class C roof covering, the exterior wall shall be permitted to terminate at the roof sheathing or deck in Types III, IV and V construction provided:
5.1. The roof sheathing or deck is constructed of approved noncombustible materials or of fire-retardant-treated wood, for a distance of 4 feet (1220 mm); or
5.2. The roof is protected with 0.625-inch Type X gypsum board directly beneath the underside of the roof sheathing or deck, supported by a minimum of nominal 2-inch (51 mm) ledgers attached to the sides of the roof framing members, for a minimum distance of 4 feet (1220 mm).
6. Where the wall is permitted to have at least 25 percent of the exterior wall areas containing unprotected openings based on the location from a lot line as determined in accordance with Section 704.8.
704.11.1 Parapet construction.
Parapets shall have the same fire-resistance rating as that required for the supporting wall, and on any side adjacent to a roof surface, shall have noncombustible faces for the uppermost 18 inches (457 mm), including counterflashing and coping materials. The height of the parapet shall not be less than 30 inches (762 mm) above the point where the roof surface and the wall intersect. Where the roof slopes toward a parapet at a slope greater than two units vertical in 12 units horizontal (16.7-percent slope), the parapet shall extend to the same height as any portion of the roof within a fire separation distance where protection of wall openings is required, but in no case shall the height be less than 30 inches (762 mm).
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