APPENDIX C: STORM AND SANITARY SEWER DESIGN FACTORS
Section
1. Storm sewer design factors
2. Sanitary sewer design factors
1 STORM SEWER DESIGN FACTORS.
MINIMUM GRADES "SMOOTH PIPE"
Using an "n" factor of 0.013, the following grades of pipe line shall be considered minimum:
Pipe Size (Inches) | Minimum Grade (Percent) |
12 | 0.33 |
15 | 0.23 |
18 | 0.18 |
21 | 0.14 |
24 | 0.12 |
For sizes larger than 24 inches where an "n" factor other than 0.013 is used, the minimum grade shall be considered as that which produces a full flow velocity of not less than 2-1/2 feet per second.
MAXIMUM INLET TIMES
Inlet time shall be computed by the design engineer. However, the maximum inlet time shall be as follows:
Distance of Travel to Inlet (Feet) | Inlet Time (Minutes) |
100 | 12 |
200 | 16 |
300 | 20 |
(Ord. 91-35. Passed 5-20-91.)
S 2 SANITARY SEWER DESIGN FACTORS.
FLOW CRITERIA
Occupant per dwelling = 2.7
Average daily flow per occupant = 62 gallons per day
* Peak flow factor per lateral and submain sewers = 4.0
* Peak flow factor for main, trunk and outfall sewers = 2.5
* Sewer classification shall be determined by the Village.
MINIMUM PIPE GRADES
Using an "n" factor of 0.013, the following grades of pipe shall be considered minimum:
Main Size Minimum Grade
(Inches) (Percent)
6 0.60
8 0.40
10 0.28
12 0.22
For sizes larger than twelve inches, the minimum grade shall be considered as that which produces a full flow velocity of not less than two feet per second.
(Ord. 93-31. Passed 11-15-93.)
TABLE
STREET DESIGN STANDARDS
STREET CLASSIFICATION | MINIMUM RIGHT-OF- WAY (FEET) | MINIMUM PAVEMENT WIDTH (FEET) | MAXIMUM DEGREE OF CURVATURE (ARC DEFINITION) | MINIMUM RADIUS OF CURVATURE (f) (FEET) | MAXIMUM PERCENT OF GRADE | VERTICAL VISIBILITY (FEET) (g) | MINIMUM CORNER RADII (FEET) (d) |
Major arterial thoroughfare | 100 a. | b. | 3º | 1,910 | 4.0% | 500 | b. |
Minor arterial thoroughfare | 80 a. | b. | 5º | 1,150 | 5.0% | 300 | b. |
Collector thoroughfare | 60 a. | b. | 10º | 575 | 6.0% | 250 | b. |
Local street (commercial or industrial) | 50 a.g. | 30 | 10º | 575 | 6.0% | 250 | 40 |
Local residential streets and cul-de-sacs | 50 a.g. | 28 | 20º | 290 | 7.0% c. | 200 | 25 |
Private streets | 50 a. | 22 | 29º | 200 | 8.0% c. | 200 | 25 |
NOTES:
a. Where a boulevard-type street is proposed, the minimum right-of-way shall be increased by an amount equal to the width of the proposed median.
b. Requirement will vary with design speed and capacity (to be determined by the Village Engineer).
c. Maximum may be greater due to topography if in accord with the application of standard engineering practice (to be approved by the Village Engineer).
d. Right-of-way line of street.
e. Pavement width dimensions are minimum measured from face to face of curb.
f. Radius of curvature is measured along centerline of streets.
g. Dimensions for distance of vertical visibility shall be measured from a point three and one- half feet above the street surface on one side of a vertical curve to a point six inches above the street on the opposite side.
CODIFIED ORDINANCES OF LEXINGTON