[Little]

Whats the max slope percentage you have seen or done on a 4" sewer lateral? I just installed (3) 4" laterals connecting to an 8" main and all of them are at 10 to 13% of slope. The inverts are per plan but it calls for 2% but i know that is a minimum usually.

 

[WC&T]

Whats the max slope percentage you have seen or done on a 4" sewer lateral? I just installed (3) 4" laterals connecting to an 8" main and all of them are at 10 to 13% of slope. The inverts are per plan but it calls for 2% but i know that is a minimum usually.

10 - 13% is screaming for sewer. I am assuming your main is pretty deep to run a lateral at that kind of slope. Usually we 45 up from the wye in the main line and 45 again at the proper invert to give us 2% fall to the building connection. Usually a clean out is called for at the upper 45 bend. It will also make it alot easier since you are not trenching so deep for as long.

 

[greg24k]

If I am not mistaken I think the minimum is 1% for private and 2 % for public unless spec's call for more.

 

[Ayerzee]

dunno, I thought if it was more than a few percent the solids would separate from the liquids

 

[rino1494]

10 - 13% is screaming for sewer. I am assuming your main is pretty deep to run a lateral at that kind of slope. Usually we 45 up from the wye in the main line and 45 again at the proper invert to give us 2% fall to the building connection. Usually a clean out is called for at the upper 45 bend. It will also make it alot easier since you are not trenching so deep for as long.

We do the same thing :thumbsup:

 

[greg24k]

When you doing a sewer connection typically, you have a starting elevation and ending elevation. Then you determine your pitch by measuring the difference in elevation between start and finish points and divide the number of horizontal feet of run into the number of inches of fall which will give you drop per foot. On the sewer pipe the drop should not be more then 1/4", because if your have to big of a pitch, water will run faster then s^*t. Suggested pitch for 4" pipe is 1/8" to 1/4" per foot...especially now its important not to have a big pitch, because this day and age you can use a 3" pipe from the house to the curb.

 

[Little]

Each run was approx 32LF. I really don't wanna have to dig all three of these back up as its the digging is tough due to space in that area and a storm line i crossed under. All three laterals are in a landscape area, but the deepest one is the one i'm really thinking about fixing as I have to pour a 40ft x 7ft wide AC unit concrete pad over the area of the lateral. The other two i'm thinking about just leaving as is and if does become a problem come back and fix it at a later time. Or am I thinking a little bit stupid here? To fix the deep one i was going to just do a straight drop of the 3ft right there at the bldg and then from there run my 2% which is called for on the plan.

I still cannot find anything that tells me what the maximum slope you really should put on a 4" sewer lateral, it has to be way more than 2% no?? I mean i have installed 8" mains at 5% before per plan without a problem and correct me if i'm wrong but can't you run more pitch the small you get with the pipe?

Thanks for the help either way.

 

[Little]

Oops forget to mention, everyone keeps telling me that well you can't put so and so pitch on the pipe because the dook seperates from the paper but then i ask them who told you and with what proof this happens they never have an answer. Its always um someone told me that. Does any have evidence of this or have had this happen to them?

 

[dayexco]

tell you the truth? i wouldn't worry about it.

 

[Framer53]

Oops forget to mention, everyone keeps telling me that well you can't put so and so pitch on the pipe because the dook seperates from the paper but then i ask them who told you and with what proof this happens they never have an answer. Its always um someone told me that. Does any have evidence of this or have had this happen to them?

If that was true all two story homes would have problems as most of the time it is a straight drop down.

 

[Little]

Day, you know what, i spoke with my father about it just a bit ago and he is saying the same thing... don't worry about it. Its just one of those things that you just can't stop thinking about.

 

[Upchuck]

I wouldn't worry about it either but we do use 45's as was described before. Many towns we work in require 6" pvc for single family homes.

 

[Framer53]

I wouldn't worry about it either but we do use 45's as was described before. Many towns we work in require 6" pvc for single family homes.

Did I read that right, 6 inch?

wow!

 

[Ayerzee]

Oops forget to mention, everyone keeps telling me that well you can't put so and so pitch on the pipe because the dook seperates from the paper but then i ask them who told you and with what proof this happens they never have an answer. Its always um someone told me that. Does any have evidence of this or have had this happen to them?

Never seen or heard of it actually happening, the sewer director from our county just told us that one time as we were putting in a lateral, I don't remember what he said the max slope was.

 

[greg24k]

Don't forget to put a few clean-outs so you don't have worry about digging it back up :thumbsup:

 

[Cuda]

If that was true all two story homes would have problems as most of the time it is a straight drop down.

When things go down the vertical stack in the house they come down in a circular motion, at high speed, then it jumps at the bottom 90 and goes horizontal to leave the house. Then the waste is staying on the bottom of the pipe. And 2% is the preferred grade so that the solids don't separate from the liquids. Sometimes as the side sewer leaves the house you need more angle to get to a lower pipe and you try to use 22's or 45's to reduce the jump in the pipe. I have never looked I wonder if utube has any clear pipe videos that show this.

 

[Cuda]

On the original question almost everything is written to maintain grade, not a lot on too much lol! But some cities and counties have rules if you exceed 50% slope the fitting at the bottom must be restrained meaning no gasket sdr 35 fittings and instead use schedule 40 or 80 pvc solvent weld or restrained joint iron pipe.

 

[PipeGuy]

The inverts are per plan but it calls for 2% but i know that is a minimum usually.

...i ask them who told you and with what proof this happens...Its always um someone told me that.

There's probably no standard specifications or standard details defined in your contract and most plans aren't worth the paper they're printed on. Just slam the pipe in and keep gettin' up. It'll be fine at whatever grade or elevation you decide works best. It's only a sewer anyway. If it backs up far enough it'll flow.

 

[Framer53]

When things go down the vertical stack in the house they come down in a circular motion, at high speed, then it jumps at the bottom 90 and goes horizontal to leave the house. Then the waste is staying on the bottom of the pipe. And 2% is the preferred grade so that the solids don't separate from the liquids. Sometimes as the side sewer leaves the house you need more angle to get to a lower pipe and you try to use 22's or 45's to reduce the jump in the pipe. I have never looked I wonder if utube has any clear pipe videos that show this.

I guess then I must just be lucky. The pipe leaves my house at 6' below grade, 4 feet above road grade less than 25' away. The sewer is 4' below the street. Now explain to me again how that works...:whistling

 

[Cuda]

I just did lol, when the solids get left in the sewer they wait till the next run of liquids comes down to further move them in the pipe. Another thing to worry about on too much grade nowdays is low flush toilets, not as much water as the old days and more and more clogs in lines that have no root intrusions.