Pipe Size, inches (inside diameter) | Minimum Grade, %(to provide at least 2 fps velocity) | Maximum Grade, %(to prevent more than 8 fps velocity) |
Pipe Size, inches (inside diameter) | Minimum Grade, %(to provide at least 2 fps velocity) | Maximum Grade, %(to prevent more than 8 fps velocity) |
6" | 0.60% | 5.62% |
8" | 0.36% | 3.83% |
10" | 0.24% | 2.84% |
12" | 0.20% | 2.23% |
15" | 0.16% | 1.65% |
18" | 0.12% | 1.30% |
See TCEQ rules for larger sizes. | ||
Plan grades shall not have vertical grade changes except at manholes. Vertical curves shall not be allowed.