Maximum Trench Widths One Foot Above Top of Pipe
| |
---|---|
Pipe Size
(inches)
|
Trench Width
|
8 to 12
|
30 inches
|
15 to 18
|
OD plus 16 inches
|
21 to 27
|
OD plus 18 inches
|
30 to 36
|
OD plus 24 inches
|
Note: "OD" is outside diameter of pipe barrel.
|
Class of Concrete
| |
---|---|
Class I
|
4000 psi at 28 days
|
Class II
|
3000 psi at 28 days
|
Class III
|
2500 psi at 28 days
|