Piping for sump pump discharge

[drhenne]

I am working on a design for a sump pump discharge for the basement of a church located in southeast Pennsylvania. The pump discharge is 1 1/2" PVC. I need run the pipe a total of 175 feet to a curb side gutter. The existing grade is approximately 2% . The pipe will cross under a public alley (15 feet macadam) and through the gravel parking lot of the church (160 feet).
Ideally, the section through the gravel parking lot should be perforated to reduce the amount of water reaching the curb. Do to existing outlet, grade and curb limitations, I can only provide a little over 6" of cover. My concerns are :

1. Crushing of the pipe under traffic.

2. Freezing of the water in the pipe.

Can anyone provide me with technical assistance and product recomendations for this application ?

 

[hopk]

Your choice of pipe coupled with the length you are running will probably result in excessive head loss, thus rendering your pumps ineffective - unless of course the discharge is minimal.

For pipes running under vehicular loads, the ground cover is inadequate - you run the risk of having the pipes damaged without warning. Material should be ductile iron and cast in concrete if there is insufficient cover.

Hope that helps

 

[MechanicalJoint]

It's hard to believe that you need to reduce the amount of water on the curb. A 1-1/2" pipe only convey about 32 gpm at 5 ft/sec...thats less than 0.1 cfs. Anyway...

I don't think that ductile iron comes in 1-1/2" in our area at least. You may consider Schedule 80 steel with as much cover as possible.

Regarding freezing, you can remove the check valve on the main and allow it to drain back into the sump...but beware...you will need to adjust your float elevations to acccomodate the fluid draining back. That is, you don't want the pumps to fill the line, shut off, drain back, etc...

Hope this helps

 

[n3rei]

I assume your 2% grade is to the curb. You may want to look into dumping by gravity into an inlet or manhole to obtain the cover. Gravity can be accomplished by using a 6" pipe at a point just ouside the building, sort of the same kind of setup you would use on a washing machine outlet. if possible outlet into a drainage swale by gravity. Something else you may want to consider is running you pipe 4' below grade to a point just ouside of the curb, bring it straight up to a 6" pvc outlet 1' above grade. try to get the up-pipe to drain back down. What I amtrying to instill is that freezing will be a problem in early and late winter where the ground water will penetrate more freely and night time freezing will occur. During the spring the night time temperatures are higher and the rain is heavier and should not cause any freezin problems, but think it out!!!