Using A 90 For Cleanout At End Of Main?

cexcavation

I have a logic question. I missed an important plan detail on a project, and as a result I ended up using the information given to me by a large pipe supplier in the area. We extended an existing sewer main by dropping a new manhole at the existing clean-out and proceeded to run 110' to the end of the project. The pipe supplier sent me an 8" 90 deg elbow of which we installed. The engineer never said anything, and it is now buried. Problem is, standard detail drawings specify two 45's Ultimately it is my mistake and if they make us dig it back up then I have zero problems doing so. However, my question is wouldn't the 90 serve as a one-way clean out especially considering that the manhole is going to be utilized 99% of the time for any maintenance. The original problem with the project is that the engineer assumed that the existing clean-out was a 90 but was instead a standard double bend 45. This in turn left us without enough room to tie in the manhole and thus we had to move it forward in order to grab a good clean run of existing sewer. Moving forward, the plans call for the sewer to stay on grade until the very end of the project..A 90 is in fact the same profile as a 1-way clean-out so why would this be a problem? I am a little frustrated that I missed this in the beginning and everyone's "logic" led us down the path of placing a 90 at the end. I'm sure you have all been in similar situations where you thought you were following the plans to a tee and then later find something in the small print that changes everything Thanks for any comments.

rino1494

Hmmm....every sewer authority that I have dealt with doesn't want to end a main with a cleanout, but they want a manhole. Personally, I would rather have a 90 instead of (2) 45's. With (2) 45's there is greater stress on the joint's from the backfill and could cause a leak or breakage. In my experience with inspectors, I doubt that anyone would discover your mistake.

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dayexco

unless they want to get a jetter/cleaning equipment thru it

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cexcavation

This project has been somewhat plagued with an engineer that seems to like to be in the office more than on the jobsite to run questions by etc. Thus I am at the mercy of what the plans state, and everything about the plans would require a 90 to be in place at the clean-out. I too agree that in this situation the 90 is better for many more reasons than 2 45s. This city does not require a manhole unless the run is over a certain length with a certain amount of laterals, etc. If you follow the plans, you end up with a sewer that is spec'd out to stay on grade and extend to the end of project to the clean-out. The elevations and scale suggest the same. The initial manhole placement was the same story-the only way the plans would have worked would be if the existing clean-out was a 90 of which it was not. Point being I did everything according to plan and it has passed all inspections with flying colors. The only problem is that I happened to check through all of the standard details and the city has a double-45 spec'd out for their standard clean-out. I imagine this is for a vac truck etc. However, the new manhole we placed is 110" feet away so it seems this shouldn't be an issue. My biggest concern is more for future use, as I don't want my work to cause another guy a headache like the one we encountered with regards to the existing infrastructure. The one thing that I would change about our trade is the inconsistencies with regards to municipalities. Depending on what city I am working in determines what the "right way" of doing something is. No matter the logic, if it's on paper then you have to re-learn everything you thought to be correct. Funny thing is, no one seems to offer up any warnings, advice, etc. until after it is buried seven feet in the ground and the engineer that was supposed to be present for daily site visits is busy at the office. On one hand it is a compliment that they trust what they have seen thus far to leave me on my own for a week straight, but you know us excavators..........we can do a lot of damage in a weeks time Man I love this stuff despite the hassles we encounter at times......always a challenge and always something new to learn.

Thanks for the input guys,
Jason

dayexco

personally, i'd take the 2-45's hands down, 90's on sewers are trouble.

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cexcavation

I agree in most cases, and definately hands down in a flow situation. However, there is always that situation that differs and I think this may be one of those cases. Also if you take a standard one way clean-out and hold a standard 90 next to it, the profiles are identical with regards to physical access to the line. Taking that into consideration, a lot of the phobia associated with using 90's for clean-outs is somewhat un-founded if a one way or two way clean-out is deemed adequate-they are the same thing only one is midstream whereas the other (the 90) is at the head of the stream. Just one of those things that comes up and is good food for thought. I typically use 90's for clean-outs on all French drains since typically I want to extend the drain directly against whatever I am trying to protect. This sewer system is designed around the idea that the sewer stays on grade right to the clean-out station.

dayexco

the theory behind using 2-45's...is that it will give you a more gradual sweep on your radius allowing cleaning equipment a better chance of making the curve.

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john1066

What i probably would have done is a twye with a 45 and a plug in the end. you would have left it set up for the next guy to take off or your self if you could get the next part of the job.