ANSI/ASTM
|
D 3034
|
(4"—15")
|
ASTM
|
F 679 Type I
|
(18"—27")
|
Manhole Diameter
(feet)
|
Wall Thickness
(inches)
|
---|---|
4
|
5
|
5
|
6
|
6
|
7
|
6 1/2
|
7 1/2
|
7
|
8
|
8
|
9
|
Manhole Depth
(feet)
|
Manhole Diameter
(feet)
|
Time to Drop 1 inch Hg
(inches)
|
---|---|---|
10 or less
|
4
|
120 seconds
|
10 to 15
|
4
|
150 seconds
|
15 to 25
|
4
|
180 seconds
|
For five-foot diameter manholes, add 30 seconds to the times
above.
|
For six-foot diameter manholes, add 60 seconds to the times
above.
|