City of Ann Arbor SSWWEP - Citizens Advisory Committee Coordination - 2.10 -C- What are the allowable flow rates for 2", 4", 6", and larger sanitary and surface water pipes?

2.10 -C- What are the allowable flow rates for 2", 4", 6", and larger sanitary and surface water pipes?

Posted by Lori Byron on 20 Dec, 2013
Category: Category 2 - about potential recommendations

Frank Burdick’s Log Number: 28

Submitted by: Burdick’s Log

Category (1,2,3): 2

Status: Closed

Estimated date to address: N/A

Q. What are the allowable flow rates for 2", 4", 6", and larger sanitary and surface water pipes?

A.The allowable flow rate of a pipe is dependent on not only its diameter, but also its slope and material. The pipe slope affects the velocity and carrying capacity of a pipe, and the material affects the friction in the pipe, which affects the carrying capacity. There are standard publications that tabulate the carrying capacity of standard concrete pipes laid at minimum slope, where the minimum slope is established to prevent the settling of sediment and debris in the pipe (maintain sufficient scouring velocity). One such standard publication is attached. It is uncommon to build new sanitary sewer pipes that a are smaller than 8-inch, and for that reason, the enclosed standard publications begins at 8-inch diameter pipes. Carrying capacities for smaller pipes can be determined through a hydraulic computation, and will be performed with the hydraulic model where relevant and necessary. We can provide that data where relevant for specific pipes in the City’s system.

Comments

Frank Burdick on 7 Jan, 2014:

This response does not address the intent of the question, which is to determine if the diameter of new horizontal bored curb line is adequate to handle multiple concurrent sump pump discharges. See also, question #77 that reads," OHM has indicated that the October 31,2013, flow test performed on the horizontal bored curb line included 5 total FDD homes. It has also been stated that the location of many existing catch basins is such that only a limited number of homes (5,6,7,8) are connected to the new curb line before being discharged into the nearest catch basin. On Winsted Blvd, there is only one catch basin to handle the entire cul de sac. There are 10 to 12 homes per each side of the street. Will the capacity of the new horizontal bored curb line be adequate to accept the simultaneous flow from 10 to 12 FDD sump pumps?

Lori Byron on 8 Jan, 2014:

Robert, is this a question you can address?

City of Ann Arbor SSWWEP - Citizens Advisory Committee Coordination — City of Ann Arbor

2.10 -C- What are the allowable flow rates for 2", 4", 6", and larger sanitary and surface water pipes?

Comments