cmp pipe riser

[john88]

I have a question regarding 18" diameter corrugated metal pipe riser used for storm drainage? Does anybody know if there is a limit to the maximum depth for the riser? i.e. the difference between the top of grate/inlet elevation and the bottom elevation where it connects to the storm drain pipe. The riser pipe will be surrounded by dirt all around. I have a situation where the depth of the cmp riser pipe is about 26 feet.

Thanks

 

[bltseattle]

I recommend checking with the party responsible for maintaining this facility. Some agencies have equipment such as vactor trucks that have a limit in the reach of the hose. The CMP manufacturer should be able to tell you about the required pipe thickness and recommend additional structural supports that could be needed.

 

[dicksewerrat]

CMP has a design life of only 25 years when it gets wet and then dries and gets wet again unless you use a pipe with a very good coating. Use concrete.