§ 91-20. Design standards.

Sewer design shall be in accordance with the following provisions:

A. 

Pipe shall be of a type approved by the Village Engineer.

B. 

Trench widths, as measured just above crown of the pipe, shall not exceed the following:

Pipe Diameter (inches)	Trench Width
8	3 feet 3 inches
10	3 feet 6 inches
12	3 feet 9 inches

C. 

If the trench widths are found during field inspection to exceed the limits in the above table, the sewer pipe shall be encased with a minimum of six inches of concrete. Pipe shall be firmly and evenly bedded on a minimum of three inches of No. 1A or No. 1 crushed stone, New York State Department of Transportation specification. Pipe thickness and field strength shall be calculated on the following criteria:

(1) 

Safety factor: 1.5.

(2) 

Load factor: 1.7.

(3) 

Weight of soil: 120 pounds per cubic foot.

(4) 

Wheel loading: 16,000 pounds.

D. 

Utilizing the above information, design shall then be made as outlined in Chapter IX of the Water Pollution Control Federation Manual of Practice No. 9, Design and Construction of Sanitary and Storm Sewers.