Home Repair (alt.home.repair) For all homeowners and DIYers with many experienced tradesmen. Solve your toughest home fix-it problems.

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
  #1   Report Post  
Posted to alt.home.repair
j probose
 
Posts: n/a
Default waste pipe slope: how much is too much?

I am planning the installation of a waste pipe (either 3" or 4") over a
distance of 46 feet. The drop in elevation over that distance is 30",
which I calculate to be aprx .65 inches per foot (instead of the nominal
..25 inches per foot). Is .65 inches per foot too much? I COULD
excavate more at the high end, and come closer to the .25 inche per
foot, but is it worth the extra effort? Also, does the pipe size make a
difference?
  #2   Report Post  
Posted to alt.home.repair
Speedy Jim
 
Posts: n/a
Default waste pipe slope: how much is too much?

j probose wrote:

I am planning the installation of a waste pipe (either 3" or 4") over a
distance of 46 feet. The drop in elevation over that distance is 30",
which I calculate to be aprx .65 inches per foot (instead of the nominal
.25 inches per foot). Is .65 inches per foot too much? I COULD
excavate more at the high end, and come closer to the .25 inche per
foot, but is it worth the extra effort? Also, does the pipe size make a
difference?


The only problem with too much slope is that
velocity will be higher and solids *may*
tend to settle out.

4" pipe will have lower velocity, so may help
a bit. In the end, you probably won't have
any problems with this run.

I would install cleanout TEE's brought up to the
surface at each end.

Jim
  #3   Report Post  
Posted to alt.home.repair
Goedjn
 
Posts: n/a
Default waste pipe slope: how much is too much?

On Wed, 21 Dec 2005 16:29:04 -0600, j probose
wrote:

I am planning the installation of a waste pipe (either 3" or 4") over a
distance of 46 feet. The drop in elevation over that distance is 30",
which I calculate to be aprx .65 inches per foot (instead of the nominal
.25 inches per foot). Is .65 inches per foot too much? I COULD
excavate more at the high end, and come closer to the .25 inche per
foot, but is it worth the extra effort? Also, does the pipe size make a
difference?



Yes, that's too much. You should go for between 1/8" and 1/2" per
foot, trying for as close to 1/4" per foot as you can get.

  #4   Report Post  
Posted to alt.home.repair
bill allemann
 
Posts: n/a
Default waste pipe slope: how much is too much?

go as far as possible with the standard slope (.125/.25" pf) and for
whatever elevation is remaining,
make a jog with a pair of 1/8 bends. do not use ells for this. you must be
able to run a cable through it.

bill


"j probose" wrote in message
.. .
I am planning the installation of a waste pipe (either 3" or 4") over a
distance of 46 feet. The drop in elevation over that distance is 30",
which I calculate to be aprx .65 inches per foot (instead of the nominal
.25 inches per foot). Is .65 inches per foot too much? I COULD excavate
more at the high end, and come closer to the .25 inche per foot, but is it
worth the extra effort? Also, does the pipe size make a difference?


  #5   Report Post  
Posted to alt.home.repair
Bob S.
 
Posts: n/a
Default waste pipe slope: how much is too much?


j probose wrote:
I am planning the installation of a waste pipe (either 3" or 4") over a
distance of 46 feet. The drop in elevation over that distance is 30",
which I calculate to be aprx .65 inches per foot (instead of the nominal
.25 inches per foot). Is .65 inches per foot too much? I COULD
excavate more at the high end, and come closer to the .25 inche per
foot, but is it worth the extra effort? Also, does the pipe size make a
difference?


I have that much slope or a little more and have had no problems in the
12 years it has been installed. People will tell you that too much
slope will leave solids behind, and it may for a short time. But when
you use the bath tub, washer, or flush without solids, the solids will
wash down to their intended location. Now if you had a run of a couple
of hundred feet it may be a different story, but 46' should not give
you a problem.

Bob S.



  #6   Report Post  
Posted to alt.home.repair
Andy Asberry
 
Posts: n/a
Default waste pipe slope: how much is too much?

On Wed, 21 Dec 2005 22:42:25 GMT, Speedy Jim wrote:

j probose wrote:

I am planning the installation of a waste pipe (either 3" or 4") over a
distance of 46 feet. The drop in elevation over that distance is 30",
which I calculate to be aprx .65 inches per foot (instead of the nominal
.25 inches per foot). Is .65 inches per foot too much? I COULD
excavate more at the high end, and come closer to the .25 inche per
foot, but is it worth the extra effort? Also, does the pipe size make a
difference?


The only problem with too much slope is that
velocity will be higher and solids *may*
tend to settle out.


Jim



I've heard this all my life. Not wanting to start a war but can
someone prove it is true?

I just don't buy it; for a couple of reasons. Sediment doesn't settle
out in a flowing stream. It only settles in eddies or broad flat
stretches with slow flow.

Even if it is true, the second flush liquid will push the first flush
solids.

And the ultimate slope, a vertical drop, doesn't seem to be a clog
problem due to settling.
  #7   Report Post  
Posted to alt.home.repair
Bill Kearney
 
Posts: n/a
Default waste pipe slope: how much is too much?

And the ultimate slope, a vertical drop, doesn't seem to be a clog
problem due to settling.


Vertical has gravity working for it along with no drag. A steeper than
appropriate drop could certainly have issues with solids settling on it.
The flow ends up being 'too quick' and moves over the solids instead of just
pooling up slightly behind it and forcing it along. I think there's also
the issue with how solids might build up over time. I'm sure there's a more
scientific explanation out there.

  #8   Report Post  
Posted to alt.home.repair
mm
 
Posts: n/a
Default waste pipe slope: how much is too much?

On Thu, 22 Dec 2005 23:05:26 -0500, "Bill Kearney"
wrote:

And the ultimate slope, a vertical drop, doesn't seem to be a clog
problem due to settling.


Vertical has gravity working for it along with no drag. A steeper than
appropriate drop could certainly have issues with solids settling on it.
The flow ends up being 'too quick' and moves over the solids instead of just
pooling up slightly behind it and forcing it along. I think there's also


I don't get it. Why wouldn't this be even worse with an average drop?
The liquid would go slower but so would the solids.

the issue with how solids might build up over time. I'm sure there's a more
scientific explanation out there.



Remove NOPSAM to email me. Please let
me know if you have posted also.
  #9   Report Post  
Posted to alt.home.repair
Stubby
 
Posts: n/a
Default waste pipe slope: how much is too much?

Bill Kearney wrote:
And the ultimate slope, a vertical drop, doesn't seem to be a clog
problem due to settling.



Vertical has gravity working for it along with no drag. A steeper than
appropriate drop could certainly have issues with solids settling on it.
The flow ends up being 'too quick' and moves over the solids instead of just
pooling up slightly behind it and forcing it along. I think there's also
the issue with how solids might build up over time. I'm sure there's a more
scientific explanation out there.

The most important feature should be that during the entire run, you
always proceed toward larger pipes.
Reply
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules

Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Are all 32mm waste pipe standard size? Stevie UK diy 4 October 19th 05 07:04 PM
Sizing of waste pipe for washbasin Tony UK diy 2 June 10th 05 12:39 AM
Flexible 43mm Waste Pipe? [email protected] UK diy 8 June 6th 05 08:08 PM
plastic air pipe CampinGazz Woodworking 8 February 9th 04 12:24 PM
Replacing old steel water main supply pipe Pandora UK diy 3 January 24th 04 09:53 AM


All times are GMT +1. The time now is 09:14 AM.

Powered by vBulletin® Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright ©2004-2024 DIYbanter.
The comments are property of their posters.
 

About Us

"It's about DIY & home improvement"