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 FIRE
WALLS
SECTION 705
705.1 General . Each
portion of a building separated by one
or more fire walls that comply with the provisions
of this section shall be considered a separate building. The extent and
location of such fire walls shall provide a complete separation. Where a
fire wall also separates groups that are required to be separated by a
fire barrier wall, the most restrictive requirements of each separation
shall apply. Fire walls located on property lines shall also comply with
Section 503.2. Such fire walls (party walls) shall be constructed
without openings.
705.2 Structural Stability.
Fire walls shall have sufficient structural stability under fire
conditions to allow collapse of construction on either side without
collapse of the wall for the duration of time indicated by the required
fire-resistance rating.
705.3 Materials.
Fire walls shall be of any approved noncombustible materials. The fire
resistance of concrete or masonry firewalls shall be calculated in
accordance with Section 720 or determined by test in accordance with
ASTM E-119. All other firewalls shall be tested in accordance with ASTM
E-119. Firewalls tested in accordance with ASTM E-119 shall be conducted
using the alternative hose stream test procedure described in Section
11.3 of ASTM E-119.
Exception:
Deleted
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North Carolina:
|
TABLE 705.4 FIRE
WALL FIRE-RESISTANCE RATINGS |
|
GROUP |
FIRE-RESISTANCE
RATING (hours) |
|
A, B,
E, H-4, I, R-1, R-2, U |
3a |
|
F-1,
H-3b, H-5, M, S-1 |
3 |
|
H-1,
H-2 |
4b |
|
F-2,
S-2, R-3, R-4 |
2 |
|
a. Walls
shall be not less than 2-hour fire-resistance rated where
separating buildings of Type II or V construction.
b. For Group
H-1, H-2 or H-3 buildings, also see Sections 415.4 and 415.5. |
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South Carolina:
VIEW ALL SC
APPROVED CODE AMENDMENTS, GO TO http://www.llr.state.sc.us/POL/BCC/index.asp?file=MODIFICATION_Main.htm
|
TABLE 705.4 FIRE
WALL FIRE-RESISTANCE RATINGS |
|
GROUP |
FIRE-RESISTANCE
RATING (hours) |
|
A, B,
E, H-4, I,R-1, R-2,U |
3 |
|
F-1,
H-3b, H-5, M, S-1 |
3 |
|
H-1,
H-2 |
4b |
|
F-2,
S-2, R-3, R-4 |
2 |
|
b. For Group
H-1, H-2 or H-3 buildings, also see Sections 415.4 and 415.5. |
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Calculated Fire Resistance of
Concrete Masonry Units (CMU)
720.1 General.
The provisions of this section contain procedures by which the fire
resistance of specific materials or combinations of materials is
established by calculations. These procedures apply only to the
information contained in this section and shall not be otherwise used.
The calculated fire resistance of concrete, concrete masonry, and clay
masonry assemblies shall be permitted in accordance with ACI 216.1/TMS
0216.1
720.3 Concrete masonry.
The provisions of this section contain procedures by which the
fire-resistance ratings of concrete masonry are established by
calculations.
720.3.1 Equivalent thickness.
The equivalent thickness of concrete masonry construction shall be
determined in accordance with the provisions of this section.
720.3.1.1 Concrete masonry unit plus finishes.
The equivalent thickness of concrete masonry assemblies, T
ea, shall be computed as the sum of
the equivalent thickness of the concrete masonry unit, Te,
as determined by Section 720.3.1.2, 720.3.1.3, or 720.3.1.4, plus the
equivalent thickness of finishes, Tef,
determined in accordance with Section 720.3.1:
Tea =
Te +
Tef
Te
= Vn/LH
= Equivalent thickness of concrete masonry unit (inch) (mm).
where:
V = Net volume of masonry unit (inch³)
(mm³).
L = Specified length of masonry
unit (inch) (mm).
H = Specified height of masonry unit (inch) (mm)
720.3.1.2
Ungrouted or partially grouted construction.
Te
shall be the value obtained for the
concrete masonry unit determined in accordance with ASTM C 140.
720.3.1.3 Solid
grouted construction.
The equivalent thickness, Te,
of solid grouted concrete masonry units is the actual thickness of the
unit.
720.3.1.4
Airspaces and cells filled with loose-fill material.
The equivalent thickness of completely filled hollow concrete
masonry is the actual thickness of the unit when loose-fill materials
are: sand, pea gravel, crushed stone, or slag that meet ASTM C 33
requirements; pumice, scoria, expanded shale, expanded clay, expanded
slate, expanded slag, expanded fly ash, or cinders that comply with ASTM
C 331; or perlite or vermiculite meeting the requirements of ASTM C 549
and C516, respectively.
Calculating The
Equivalent Thickness
Note: For Procedures on
Calculating the Equivalent Thickness see NCMA TEK 7-1A
If the hollow unit is 50% core
voids Its equivalent solid thickness is 4"
The core area is 40-50% gross area Equivalent thickness is the solid thickness that would be
obtained if
the same amount of concrete contained in a hollow unit were re-cast
without core holes.
Approximate
Volume in Standard Concrete Masonry Units
| Size |
Cores |
Cu ft.
to fill Cores |
% Solid
Volume |
Equivalent
Thickness Inches |
| 4x8x16 |
3 |
.06 |
73.6 |
2.66 |
| 4x8x16 |
2 |
.06 |
73.6 |
2.66 |
| 6x8x16 |
3 |
.15 |
57 |
3.21 |
| 6x8x16 |
2 |
.16 |
54 |
3.06 |
| 8x8x16 |
3 |
.22 |
53.83 |
4.10 |
| 8x8x16 |
2 |
.25 |
51.16 |
3.95 |
| 10x8x16 |
2 |
.34 |
49.27 |
4.70 |
| 12x8x16 |
3 |
.34 |
49.4 |
6.19 |
| 12x8x16 |
2 |
.40 |
44.54 |
5.62 |
*
These Units may vary with each manufacturer depending on the style of
the block, mold configuration, and wear etc.
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Table 720.3.2
2000 International Building Code Fire Resistance-Rated Construction
Minimum Equivalent Thickness (inches) of Bearing or Nonbearing Concrete
Masonry Walls
| |
Fire Resistance
Rating (hours) |
| Type of
Aggregate |
1/2 |
3/4 |
1 |
1
1/4 |
1
1/2 |
1
3/4 |
2 |
2
1/4 |
2
1/2 |
2
3/4 |
3 |
3
1/4 |
3
1/2 |
3
3/4 |
4 |
| Pumice
of expanded slag |
1.5 |
1.9 |
2.1 |
2.5 |
2.7 |
3.0 |
3.2 |
3.4 |
3.6 |
3.8 |
4.0 |
4.2 |
4.4 |
4.5 |
4.7 |
|
Expanded shale, clay or slate |
1.8 |
2.2 |
2.6 |
2.9 |
3.3 |
3.4 |
3.6 |
3.8 |
4.0 |
4.2 |
4.4 |
4.6 |
4.8 |
4.9 |
5.1 |
|
Limestone, cinders or unexpanded slag |
1.9 |
2.3 |
2.7 |
3.1 |
3.4 |
3.7 |
4.0 |
4.3 |
4.5 |
4.8 |
5.0 |
5.2 |
5.5 |
5.7 |
5.9 |
|
Calcarous of
siliccous gravel |
2.0 |
2.4 |
2.8 |
3.2 |
3.6 |
3.9 |
4.2 |
4.5 |
4.8 |
5.0 |
5.3 |
5.5 |
5.8 |
6.0 |
6.2 |
For S1: 1" = 25.4mm
a. Values between those shown in the table can be determined by
direct interpolation
b. Where combustible members are framed into the wall, the
thickness of solid material between the
end of each member and the opposite face of the wall or
between members set in from opposite
sides, shall not be less than 93 percent of the thickness
shown in the table.
c. Requirements of ASTM C55, C73 or C90 shall apply.
d. Minimum required equivalent thickness corresponding to the
hourly fire-resistance rating for units
a combination of aggregate shall be determined by linear
interpolation based on the percent by
volume of each aggregate used in manufacture. |
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