# 1/4 inch per foot equals ???



## jomama45

It's extremely close to 2 degrees........


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## TarheelTerp

jomama45 said:


> It's extremely close to 2 degrees........


I was going to start a thread about this...

I wanted to clarify the distinction between the "2%" usually referred to with longer runs and larger pipes vs the 1/4" P/LF usually referred to with shorter runs and smaller pipes.

eg: When I trench to re-route 70 linear feet of 4" main/waste pipe I'm told I can use 2% (70x12 x .02) or 16.8" because I will dearly need that 3/4" (vs 17.5").


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## jomama45

EDIT: After reading "Tarheel's" response, I realize I made a mistake. 1/4" per foot pitch equals 2%, NOT 2 degrees. I can't give you the exact answer off of the top of my head, but I'd say it's likely just under 1 degree.......

Hopefully someone else here can give you a better answer.


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## Plumber101

One degree could be equal to any length depending on how far from the point of origin you are making a measurement. It is not normally a function of length.

One degree can be broken down into 60 minutes or 360 seconds.


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## jschaben

kevin705 said:


> Hi everyone.
> 
> I know my 3 inch horizontal drain has got to be at a 1/4" per foot
> 
> My question is..
> 
> What would 1/4" per foot be equal to in degrees ?
> 
> I've looked on the internet for this answer and I havent had much luck. Your help is appreciated.


Hi Kevin: works out to 1.2°. It would be the inverse tangent of .25/12 but I just drew it out in DeltaCad and let it figure out the math:whistling2:


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## kevin705

Thanks for the answers.
If your curious , any levels that I can find find have an auto adjust for the degrees.
And for this length of pipe it'll be helpful to know what I can set it at.
Thanks Again.


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## TarheelTerp

kevin705 said:


> And for this length of pipe it'll be helpful to know what I can set it at.


I don't know anything about this whiz-bang gizmo you have, but...

If Point "A" = X" (below some known grade level or such)...
then Point "B" 100 linear feet away MUST be 24" shallower than X.
(100 x 12" x .02) 

For the 1/4" P/lf method... 100' x .25" per = 25" shallower.

If you don't have a transit...
try some clear vinyl hose with water in it.
after an annoying ad: http://www.youtube.com/watch?v=NhDbv9xMXJs

http://www.deckmagazine.com/article/64.html


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## Alan

jschaben said:


> Hi Kevin: works out to 1.2°. It would be the inverse tangent of .25/12 but I just drew it out in DeltaCad and let it figure out the math:whistling2:



To be a little more accurate : 

1.193489423982035

:laughing:


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## jaydevries

go to home depot and buy a husky plumbers level it has 1/8, 1/4, 3/8, rise marks on it just 
make sure you use it right or your pipe will be going the wrong way:thumbup:

http://www.homedepot.com/Tools-Hard...gId=101&langId=-1&keyword=level&storeId=10051


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## DexterII

Tape a shim (1" in this case) on one end of a 4' level.


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## psilva8

jaydevries said:


> go to home depot and buy a husky plumbers level it has 1/8, 1/4, 3/8, rise marks on it just
> make sure you use it right or your pipe will be going the wrong way:thumbup:
> 
> http://www.homedepot.com/Tools-Hard...gId=101&langId=-1&keyword=level&storeId=10051


Or, I've seen guys take a 4' level and tape a 1" block to the end of it.

edit: ^^^ he beat me.


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## loneframer

I have two different sizes of these levels. They convert from degrees, % and ?/12(for roof pitch). A little fun and you can convert anything you want.

http://www.sears.com/shc/s/search_1...e=CAT_REC_PRED&prop17=digital level craftsman


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## En3lson

Idk who said it, but 60 min is 3600seconds not 360s. A. And B. Yes it will ALWAYS be the EXACT same degree which boils down to 1.2 or something like that. Never the less. The degree will NEVER change bc 1/4”/‘ is a constant no matter how long a run you have. But if you were doing say a 100 footer, you’d use the 2%index.


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## HotRodx10

From my understanding of sanitary sewer systems, 1/4" /ft is the max slope, with 1/8" /ft being the minimum.


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## Ghostmaker

1/4 inch for 2 inch and 1.5 inch
1/16 inch for and 8 inch or larger
1/8 inch for 3 to 6 min pitch


No max pitch in any size under IPC. How would one got vertical?



1.2 degrees = 1/4 inch
https://learnframing.com/angle-calculator-slope-degrees/


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## HotRodx10

> No max pitch in any size under IPC. How would one got vertical?



I understood that at slopes more than 1/4"/ft, the water runs around the 'solids' and the pipe gets clogged more easily, but that is either an old wives tale or good advice from seasoned plumbers, depending on who you listen to. Apparently, the documented upper limits on slope exist to limit velocity in order to prevent erosion (wear) of the pipe walls. The consensus of the sources I read seems to be that good practice is to keep to a 1/4"/ft and then 45 down at the end into the main. Vertical pipes are obviously ok because everything just falls.


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## bruceb3

quarter bubble on you level has always worked for me. Just cracking the bubble is about 1/8" per foot.


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## Old Thomas

HotRodx10 said:


> I understood that at slopes more than 1/4"/ft, the water runs around the 'solids' and the pipe gets clogged more easily, but that is either an old wives tale or good advice from seasoned plumbers, depending on who you listen to. Apparently, the documented upper limits on slope exist to limit velocity in order to prevent erosion (wear) of the pipe walls. The consensus of the sources I read seems to be that good practice is to keep to a 1/4"/ft and then 45 down at the end into the main. Vertical pipes are obviously ok because everything just falls.



The part about solids being passed by liquids has been disproven, that is why it is not in the IRC.


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## ron45

Pssst. Construction Master 5......


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## ron45

I know a lot of you like metric so here you go.


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## Brianthedog

Maybe this app in a pinch


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## bryan83

kevin705 said:


> Hi everyone.
> 
> I know my 3 inch horizontal drain has got to be at a 1/4" per foot
> 
> My question is..
> 
> What would 1/4" per foot be equal to in degrees ?
> 
> I've looked on the internet for this answer and I havent had much luck. Your help is appreciated.


2.39 degrees is the slope of 1/4" drop per foot


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## bryan83

kevin705 said:


> Hi everyone.
> 
> I know my 3 inch horizontal drain has got to be at a 1/4" per foot
> 
> My question is..
> 
> What would 1/4" per foot be equal to in degrees ?
> 
> I've looked on the internet for this answer and I havent had much luck. Your help is appreciated.


2.39 Degrees I drew it out in solid works and let it figure the degrees


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## HotRodx10

bryan83 said:


> 2.39 degrees is the slope of 1/4" drop per foot


1/4" per foot = .25"/12" = .020833 = 2.083% = 1.1935 degrees.

2.39 degrees would be 1/2" per foot.


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## bryan83

1.93 degrees for 1/4" drop per foot
2.39 degrees for 1/2" drop per foot


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## bryan83

bryan83 said:


> 2.39 Degrees I drew it out in solid works and let it figure the degrees


I was wrong it is 1.93 degrees per 1/4" drop for 12 inchs


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## HotRodx10

bryan83 said:


> I was wrong it is 1.93 degrees per 1/4" drop for 12 inchs


1/4" per foot still equals 1.19 degrees...


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## DJLland

kevin705 said:


> Hi everyone.
> 
> I know my 3 inch horizontal drain has got to be at a 1/4" per foot
> 
> My question is..
> 
> What would 1/4" per foot be equal to in degrees ?
> 
> I've looked on the internet for this answer and I havent had much luck. Your help is appreciated.


This chart I found shows that a 2% slope equals 1.15 degrees. That sound right to me. Here is the link. Calculating Slope and Common Slopes in Architecture


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