ANSI/ASTM D 3034 (4 inches to 15 inches)
| |
ASTM F 679 Type I (18 inches to 27 inches)
|
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 One Inch Hg
(seconds)
| |
---|---|---|---|
10 or less
|
4
|
120
| |
10 to 15
|
4
|
150
| |
15 to 25
|
4
|
180
| |
For five-foot diameter manholes, add 30 seconds to the times
above.
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For six-foot diameter manholes, add 60 seconds to the times
above.
|