On occasion I have had an engineer or someone else in the chain of reviewing as-builts that insist on having the inverts of the "clean-outs" as-built. I explain the structure of a clean-out is not measure down friendly and usually the requests go away. Just wondering what others out there have encountered.
As usual - it depends
I have used a probe rod to measure down to the top of the pipe and then add the diameter (with a note that for accuracy the cleanuot should be uncovered). If the cleanout is shallow (I can see the bottom) and the grade is not critical, I measure down from the lid with a tape. Of course the most accurate way is to dig up the cleanout, but few clients want to pay for the extra.
Andy
I refer them to a plumber
I've taken the top of the cleanout and measured down. Since the wye part is not plumb I measured the distance to the rim, then double the distance on the rod and then measured down to a 4 level. Then subtracted the vertical distance to the level and provided that as the invert.
Edit: after re reading what I just posted it did not make much sense. But it did work.
This should be a plumbers problem. However, if you are going to as-built a Clean Out, I suggest doing it while it is exposed. I have been on jobs in large sub-divisions that want the entirity of their drainage, sewer, water, (you name it)located and elevated. I usualy locate the CO with GPS (then blow the EL) then come back with a level, and shoot Top of Pipe.(then edit the blown EL) This is usualy satisfactory, sometimes however they want an invert, in that case I just measure down with a box-tape and subtract from my top of pipe. Also if you stay in good comunication with the pipe crew they will usualy leave it open for you to shoot before they fill it in etc. Sometimes it's better to have your office schedule a time/day that also works for the pipe crew. Unless you feel like running a probe, and spade all day. To answer your question as to why they want an EL, I really couldn't tell you. Most engineers work from an office and really can't visualize things we see in the feild every day. I can understand wanting a horizontal position, but an invert is a tad redundant...
Our local powers that be in the city require that sometimes for a certificate of occupancy. I say 'sometimes' because it depends on who you talk to and whether it's before or after lunch. I tell them the invert below the clean out valve isn't necessarily straight into the sewer line.
99.9% of cleanout wyes are
45 degrees. Slide your grade rod to the bottom, read the distance to the rim and the rest is simple geometry. Sheesh.
-JD-:-S
99.9% of cleanout wyes are
Clean outs in my area are not 45 degrees. They are almost always like this ... and you can slip a thin peice of wood through the bend all the way to the bottom. Maybe these are required by a county code, because I've never seen a 45 degree wye.
JD and TPR....ya did a much
better job of explaining than my feeble attempt......many ditto's!
JD, help me with my simple geometry.
There's some of these over by the local university. It would be a BIG help if you could find the difference between the top of the cleanout valve and bottom of the flow line of the sewer. I'm having trouble figuring it out.
just guess at it and send out the bill for crissakes.
Interesting how different things are across our country. I won't allow probing after having to pay for "repairs" and our clean-outs also aren't necessarily 45°s, they vary. Thanks for all the input !