20 Ft run - 2 inch pitch

F

firkus

New Member
Messages
5
Reaction score
0
Points
0
I have a situation where a 20 ft run only has a fall of 2 inches over the entire span of the run. I'm thinking it should be at 5 inches for this distance, and I want to stop food from backing up every year. I would like to fix this, but here is my dilemma. I don't have access to one of the supports, because it is tucked away between two finished walls(bottom of stairway) and I can't reach from either side. What should I do since this 2x4 support between the floor joist will be in the way, if I set the pitch to the proper rate of decline.

I don't seem to have the ability to raise it any higher at the beginning of the run either.

Thanks
 
2 inches should be ok

you got to work with what you got ...


if you have two inches of fall, ---in 20 feet
it will most likely work great for decades

unless you are planning on pouring bacon grease directly down the line....

if you are hell bent on cuttung up the home
to get tons of fall on a 2 inch pvc pipe

go for it,

but it really is not all that necessary..

put a nice cleanout under the sink and forget about it
 
Forgetting about it is the perfect recipe for getting intimate with a drain cleaner on a regular basis. I'd fix it!
 
Looks like two different opinions

I already have a nice cleanout installed, so that part has been addressed. Does anybody know if code is only 1/8" every foot in WI? If not I want to take care of the problem, but if I am up to code, maybe we need to use our garbage disposal less.
 
code

IF code in WI allowed 1/8" pitch, then that would imply it was adequate and regardless of what the code is elsewhere it would still work. Physics do not change according to the state you live in.
 
At best, the code allows 1/8" on a 4" pipe, but I am quite sure your code would not allow 1/8 on a 2" pipe. You have the worst case, which is a garbage disposal. It is almost certain you will have recurring problems with waste buildup.

If ultimately you "do what you have to do", the best recommendation would then be to train the cooks in your house to forget about Al Gore, and run water for SEVERAL MINUTES after each use of the disposal, to try to carry any waste past this 20' run/
 
Another possibility would be to upgrade your disposer. Insinkerator's best unit (over $300) has 3 separate grinding operations so they claim that it liquifies food particles. I haven't tried it myself but plan to upgrade to that unit at some point as my kitchen waste line will clog if I put down too many carrot or potato peelings, etc.

In fact, others on this site have recommended not using a disposer for vegetable peelings at all.
 
What is code? What will work, even if not to code?

I agree with Mark; the slope will work.

A lot of it depends on the pipe. Most codes are based on what is required for cast iron pipe. That was what was used when codes were developed.

Cast iron corrodes and collects stuff inside. It is hard to maintain precise slopes. The required 1/4" per foot overcomes some of that. I found one code that allows 1/8" per foot on lines 3" and larger. http://www.charlevoixcounty.org/downloads/2003_plumbing_code_requirements.pdf . Some sewer lines are installed less than 1/16" per foot on lines 6" and larger.

PVC pipe tends to remain clean and has less roughness, reducing the tendency to collect solids, which then make a dam that uses up more of the available slope in cast iron pipe.
 
Bob NH said:
What is code? What will work, even if not to code?

I agree with Mark; the slope will work.

A lot of it depends on the pipe. Most codes are based on what is required for cast iron pipe. That was what was used when codes were developed.

Cast iron corrodes and collects stuff inside. It is hard to maintain precise slopes. The required 1/4" per foot overcomes some of that. I found one code that allows 1/8" per foot on lines 3" and larger. http://www.charlevoixcounty.org/downloads/2003_plumbing_code_requirements.pdf . Some sewer lines are installed less than 1/16" per foot on lines 6" and larger.

PVC pipe tends to remain clean and has less roughness, reducing the tendency to collect solids, which then make a dam that uses up more of the available slope in cast iron pipe.
Click to expand...

All true, Bob. But I have about a 3' trap arm on my kitchen sink drain, goes across through the cabinets, with less than ideal slope. I have tweaked the slope a little, but still any time I work under there, I look inside that arm and it gets "gunky"
 
made some calls

I was able to track down the plumbing inspector for my city and he stated that code is 1/8 inch per foot, so it looks like the plumber did things correctly. Is it common practice to add additional slope to a garbage disposal run?

If I were to purchase the "cadillac" of garbage disposals, would that help anything? Right now I'm using a Badger 5, which looks to be pretty small.

Once again thanks for the input.
 
firkus said:
If I were to purchase the "cadillac" of garbage disposals, would that help anything? Right now I'm using a Badger 5, which looks to be pretty small.
Click to expand...

I suggest you try it with what you have and see if you have a problem.
 
I do not know whether hot or cold or even some alternating might be best, but be sure to keep this mind:

jimbo said:
... run water for SEVERAL MINUTES after each use of the disposal, to try to carry any waste past this 20' run.
Click to expand...

My wife and I used to have a disposal and we never had a problem as long as that was done.
 
pitch does not matter

I dont care what your pitch is on your pipe...

if you have a garbage disposal, it is simply wise

to run the water to flush the ground particles of

garbade down the drain...


if you do not do this when running the disposal
you will face the smae fate wether you its a 2 inch pitch
or a 6 in ch pitch in 20 feet.
 
thanks - few more questions

Mark and all,

Without a doubt, I know we are to blame for the backup of food in the line. We could definitely run the water longer after each disposal occurrence.

Let me word the question now this way. If the 20 ft pipe was in your house, what pitch would you install? I have 1/8" per foot on a 2" pipe. I know a couple have already responded better my house than their house.

Would a larger garbage disposal assist in any way shape or form vs. the Badger 5?

Can you have multiple pitches in a line? If the first 10 feet are at 1/8" can the next 10 feet be at 1/4"? I'm asking because I have better access to the last 10 feet of the run.
 
of all the weired things we've had problems with causing clogs, egg shells in the garbage disposal line seems the worst. It almost becomes a mud and they stick to each other like glue.
 
Two inch pitch will work ok

two inches of fall will work ok,

again, if you can give it more, that is great

a few more inches is good , but not necessary.


but I would not absolutely go nuts cutting or
drilling a bunch of joysts over it.....


What is the problem with cleaning a little gunk out of a 2 inch line going twenty feet every 15 years anyway???
 
15 years would be fine

Mark,

My problem is that is has happened in 2 years, so maybe we were just unlucky or dumb...

Any ideas on the multiple pitch for one line? Can I increase the pitch after the 10 foot mark? Of is this a big no-no and against typical code?
 
You must log in or register to reply here.

Similar threads

M
Question about running multiple Pex supply lines along joist
Replies
2
Views
3K
MG70
M
C
Looking for help with some design questions for submersible pump
2
Replies
34
Views
3K
chickenranch
C
J
Help! This noise is driving us crazy.
Replies
2
Views
2K
jb4e_seattle
J
B
Septic Pumping/lifting Station Failure
Replies
2
Views
4K
bxdobs
B
M
Opinions on a hybrid Pex to Copper re-pipe.
Replies
2
Views
2K
MG70
M
Back
Top