Riverview Estates-CS 9610162149059595
ENGINEERING CORP 2149059.~
10-16-1996 12:09~M
I I _ IIIII .... IIII I
eOM Engineering Corp.
- . II I __ IIIIII I -
1120 Empl~$ C®nt~'al
Suits $0~
DoIIoI . Te~al
(~t4} ~0-$~00 Pox
T I1~ a, N I~ M I T T A I,,
10'/7"90 /'?,,
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!~, E M A R K .~ ,
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18-16-1996
12:09PM
FROM CCM ENGINEERING CORP 21A90S9393
P. 2
10'17'P6 ~I1:20
Where " ...... ·
IN
"q" is the flow in cubic feet per second.
"A" is the crass sectional area of the conduit in square feet·
"V" is the velocity of flow in the conduit in feet per second.
"~." iS the roughness coefficient of the conduit.
"R" ~" the hydraulic radius which is the area of flow divided by
t;.e wetted perimeter. (R.A~_,~
#$f" ~s the slope of the hydraulic gradient.
"P" is the wetted perimeter.
A section of storm seer is designed by setting its capacity equal to the
r,,lculated rurmff. The hydraulic gradient and velocity' shall be figures by this
gactty and appraprlate pipe size using the Manning flow chart, FIGURE g. As
.ng as the vel~tty is below 10 fps, minor head losses ~my be neglected except
transition boxes and mnholes. Veloctty head losses are to be accented for
pipe Ju~ttons and size changes and for pipe velocities in excess of 10 fps.
Th· crown of the pipe should be near t~e elevation of the hydraulic
gradient in most rases to eliminate excessive excavation. The hydraulic
gradient shall not be designed above the top of any.inlet. The permissible
difference between the hydraulic gradient and top of curb is normally 2 feet
ar 1.$V1Z. where Vl is the velocity in the lateral.
2.'z VELO¢.X. [.a CLOS...EO CO,,NOU_XT, S
TABLE 3 is a tabulation of mtnimum pipe grades which will produce a
ve oc;ty of not less than 2.S fps when flowing full. Grades less than those
shL.wn will not be allowed. Only those pipe sizes shown in TABLE 3 should be
used in designing pipe storm sewer systems.
TABLE 3
MINZMUM SLOPES FOR PIPES
(n-.O13)
Plpe Diameter $1 ope Pt pe Diameter
~ (Feet/100 Feet)_ ~
15
18
Zl
2¢
27
30
33
36
3g
48
Slope
(F, eet/l?O Feet
.230 - ~.,e 51 .045 '-
· 180 - A.4~, 64 .041 --
.1SO- &.H 60 .036 ~
.120- q.~ 66 .032-
.110- ~=-~q 72 .028-
.090~ ~t.s~ 78 .02S-
.070~ m n.u~ 90 .021 ~
.062- to.~b g& .019-
.056- ~-~-~ 102 . Ol 8 ~
.OS2- ~'~ 108 .016 ~
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