Elevations for outside sewer pipes

almostdone

I was hoping someone could help me understand the elevation measurements and abrieviations on a hand drawn plan from my town hall engineering dept. I am on septic and need to tie into the city sewer. I have seen plans like this before but never understood what these mean..... M.H.STA 18+21 or C.B. Rim EL. 251.79, or INV.EL. 240.63, or S=0.0064 or 8" A.C. CL 2400. Any help would be appreciated.

wsuswim147

M.H.STA 18+21- Manhole Station 18+21 (Means manhole is 1821 ft from some reference location)

C.B. Rim EL. 251.79- Catch Basin Rim Elevation. This is the elevation of the grate of the catch basin. For rectangular curb inlets, it is at the corner of the grate.


INV.EL. 240.63- Invert elevation. This is the elevation of the invert or bottom of the catch basin or sewer pipe.

S=0.0064- This is the slope of the sewer pipe in ft/ft. This is saying the sewer has a 0.64% slope.

8" A.C. CL 2400- This is your sewer pipe. It is an 8" Clay Pipe, Class 2400 (has to do with the strength of the clay pipe).

wsuswim147

Another quick note. The elevations are from some reference benchmark location. It should say on the plan where the benchmark is and what its elevation is. This will give you everythng you need to know to use a level and a rod and do measurments to make your tie-in