6.4 METHOD 1—SIMPLIFIED PROCEDURE
6.4.1 Scope. A building whose design wind loads are determined in accordance with this section shall meet all the conditions of
GCpf = product of the equivalent external pressure coefficient and gust-effect factor to be used in determination of wind loads for MWFRS of low-rise buildings
GCpi = product of internal pressure coefficient and gust-effect factor to be used in determination of wind loads for buildings
sq == psols. factor for background response in Eqs. 6-4 and 6-8
gK = peak factor for resonant response in Eq. 6-8
gv = peak factor for wind response in Eqs. 6-4 and 6-8
H = height of hill or escarpment in Pig. 6-4, in ft (m) h = mean roof height of a building or height of other structure, except that eave height shall be used for roof angle 0 of less than or equal to 10°, in ft(m)
he = roof eave height at a particular wall, or the average height if the eave varies along the wall / = importance factor /j = intensity of turbulence from Eq. 6-5 K\, kz, kt, = multipliers in Fig. 6-4 to obtain K,_,
Kd = wind directionality factor in Table 6-4
Kh = velocity pressure exposure coefficient evaluated at height z = h
Kz = velocity pressure exposure coefficient evaluated
at height z
Kzt == topographic factor as defined in Section 6.5.7 L = horizontal dimension of a building measured parallel to the wind direction, in ft (m)
Lh = distance upwind of crest of hill or escarpment
in Fig. 6-4 to where the difference in ground
elevation is half the height of hill or escarpment,
in ft (m)
Ls = integral length scale of turbulence, in ft (m) Ly = horizontal dimension of return comer for a solid
freestanding wall or solid sign from Fig. 6-20,
in ft (m)
i = integral length scale factor from Table 6-2, ft (m) n} == reduced frequency from Eq. 6-12 n\ •=- building natural frequency, Hz
p = design pressure to be used in determination of
wind loads for buildings, in Ib/ft2 (N/m2) pl^ = wind pressure acting on leeward face in Fig. 6-9, in Ib/ft2 (N/m2)
Pnei = net design wind pressure from Eq. 6-2, in Ib/ft2
(N/m2)
Pnei30 = net design wind pressure for Exposure B at h = 30 ft and / = 1.0 from Fig. 6-3, in Ib/ft2 (N/m2) pp = combined net pressure on a parapet from Eq. 6-20, in Ib/ft2 (N/m2)
ps = net design wind pressure from Eq. 6-1, in Ib/ft2
(N/m2)
Ps30 = simplified design wind pressure for Exposure B at h = 30 ft and / = 1.0 from Fig. 6-2, in Ib/ft2 (N/m2) pw = wind pressure acting on windward face in
Fig. 6-9, in Ib/ft2 (N/m2) Q = background response factor from Eq. 6-6

q = velocity pressure, in Ib/ft2 (N/m2) qit = velocity pressure evaluated at height z = h, in
Ib/ft2 (N/m2)
q, == velocity pressure for internal pressure determination, in Ib/ft2 (N/m2)
cfp = velocity pressure at top of parapet, in Ib/ft2
(N/m2) q^ == velocity pressure evaluated at height z above
ground, in Ib/ft2 (N/m2) R = resonant response factor from Eq. 6-10 rb, Rh, rl = values from Eq. 6-13
Ri = reduction factor from Eq. 6-16 Rn = value from Eq. 6-11 s = vertical dimension of the solid freestanding wall
or solid sign from Fig. 6-20, in ft (m) r = rise-to-span ratio for arched roofs
V = basic wind speed obtained from Fig. 6-1, in mi/h (m/s). The basic wind speed corresponds to a 3-s gust speed at 33 ft (10 m) above ground in exposure Category C
V, == unpartitioned internal volume ft3 (m3)
V; = mean hourly wind speed at height z, ft/s (m/s)
W = width of building in Figs. 6-12 and 6-14A and
B and width of span in Figs. 6-13 and 6-15,
in ft (m) X = distance to center of pressure from windward
edge in Fig. 6-18, in ft (m) x = distance upwind or downwind of crest in
Fig. 6-4, in ft (m)
z = height above ground level, in ft (m) z = equivalent height of structure, in ft (m) Zg = nominal height of the atmospheric boundary
layer used in this standard. Values appear in
Table 6-2 Zmi, = exposure constant from Table 6-2
a = 3-s gust-speed power law exponent from Table
6-2
a = reciprocal of a from Table 6-2 a = mean hourly wind-speed power law exponent
in Eq. 6-14 from Table 6-2
ft = damping ratio, percent critical for buildings or other structures
€ = ratio of solid area to gross area for solid freestanding wall, solid sign, open sign, face of a trussed tower, or lattice structure
>. = adjustment factor for building height and exposure from Figs. 6-2 and 6-3
6 = integral length scale power law exponent in Eq. 6-7 from Table 6-2
r] = value used in Eq. 6-13 (see Section 6.5.8.2)
6 = angle of plane of roof from horizontal, in degrees v = height-to-width ratio for solid sign

Minimum Design Loads for Buildings and Other Structures	23