Base Temperature on Which Mix is Placed
(in ° F.)
|
1 1/2" Thick
|
2" Thick
| |
---|---|---|---|
35° to 40°
|
305
|
295
| |
40° to 50°
|
300
|
285
| |
50° to 60°
|
295
|
280
| |
60° to 70°
|
285
|
275
| |
70° to 80°
|
280
|
270
| |
80° to 90°
|
270
|
265
| |
90° +
|
265
|
260
|
Distance Between Buildings
(feet)
|
Required Fire Flow
(gpm)
|
Residual Pressure Needed
(psi)
| |
---|---|---|---|
More than 100
|
500
|
20
| |
31 to 100
|
750
|
20
| |
11 to 30
|
1,000
|
20
| |
10 or less
|
1,500
|
20
|
Q = CiA
|
Where:
| ||||
Q
|
=
|
Peak rate of flow
| ||
C
|
=
|
Coefficient of runoff
| ||
i
|
=
|
Rainfall intensity in inches per hour
| ||
A
|
=
|
Area of watershed in acres
|
Roofs and pavement
|
0.90
| |
Lawns, flat (2% maximum), sandy soil
|
0.10
| |
Lawns, average (2% to 7%), sandy soil
|
0.12
| |
Lawns, steep (> 7%), sandy soil
|
0.18
| |
Lawns, flat (2% maximum), heavy soil
|
0.15
| |
Lawns, average (2% to 7%), heavy soil
|
0.20
| |
Lawns, steep (> 7%), heavy soil
|
0.30
| |
Woodland
|
0.20
| |
Wetlands, ponds, basins
|
0.90
|
Hydrologic Soils Group
| |||||
---|---|---|---|---|---|
A
|
B
|
C
|
D
| ||
Lawns, poor
|
68
|
79
|
86
|
89
| |
Lawns, fair
|
49
|
69
|
79
|
84
| |
Lawns, good
|
39
|
61
|
74
|
80
| |
Impervious areas, pavement, roofs
|
98
|
98
|
98
|
98
| |
Woods, poor
|
45
|
66
|
77
|
83
| |
Woods, fair
|
36
|
60
|
73
|
79
| |
Woods, good
|
30
|
55
|
70
|
77
| |
Wetlands, ponds, basins
|
98
|
98
|
98
|
98
|
Hydrologic Soil Group
|
Required Recharge
(inches of runoff)
| |
---|---|---|
HSG A Soil
|
0.60
| |
HSG B Soil
|
0.35
| |
HSG C Soil
|
0.25
| |
HSG D Soil
|
0.10
|
V
|
=
|
1.486
n
|
R2/3
|
S1/2
|
Where:
| ||
V is the cross-sectional average velocity (ft/s)
| ||
n is the Manning coefficient of roughness (independent of units)
| ||
R is the hydraulic radius (feet)
| ||
S is the slope of the drain line (feet/foot)
|
Q = AV
|
Where:
| ||
Q is the volume of flow in cubic feet per second
| ||
A is the cross-section area of the pipe
| ||
V is the cross-sectional average velocity (ft/s)
|
Table 2-1
Infiltration Rates for Various Soil Textures
| |||
---|---|---|---|
Texture Class
|
NRCS Hydrologic Soils Group
|
Design Infiltration Rate
(inches per hour)
| |
Sand
|
A
|
8.27
| |
Loamy sand
|
A
|
2.41
| |
Sandy loam
|
B
|
1.02
| |
Loam
|
B
|
0.52
| |
Silt loam
|
C
|
0.27
| |
Sandy clay loam
|
C
|
0.17
| |
Clay loam
|
D
|
0.09
| |
Silty clay loam
|
D
|
0.06
| |
Sandy clay
|
D
|
0.05
| |
Silty clay
|
D
|
0.04
| |
Clay
|
D
|
0.02
|
Acer rubrum
|
Red maple
| |
Celtis occidentalis
|
Common hackberry
| |
Fraxinus americana
|
White ash
| |
Liquidambar styraciflua
|
American sweetgum
| |
Nyssa sylvatica
|
Tupelo
| |
Quercus alba
|
White oak
| |
Quercus coccinea
|
Scarlet oak
| |
Quercus palustris
|
Pin oak
| |
Ulmus rubra
|
Red elm
| |
Quercus rubra
|
Red oak
|