A thread/question for the trade workers, engineers, and hydrologists... weirdos stay out!

LuckyDuck

LuckyDuck

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    • Nov 4, 2020
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    #1
    Ok,

    I've got a serious question for the smart people here on the Hide...

    Let's say that given a 2 story house, there are 2 bathrooms/toliets on the 1st floor & 2 bathrooms/toliets on the 2nd floor. Let's also say that all of the toilets are exactly the same (aside from location/elevation) and that the sewer goes out in the basement directly beneath the 1st floor. So all toilets are the same make & model and since this is America in this scenario... let's call one of the constants that all of the toilets are rated at 1.6 GPF.

    So here's my question, and yes I'm being serious here (hence I why I said no weirdos and trying to recruit educated & experienced professionals here). As a layperson, I may be using the wrong terminology but would the 2 toilets on the 2nd floor have the equivalent of a "mechanical advantage" to that of the 2 toilets on the 1st floor of the house?

    Here's why I ask- I'd have to believe that a higher elevation from the sewer throughput would be able to take advantage of gravitational pull but, as we all learned in school, gravitational pull is constant (9.8 m/s^2 if I remember my schooling from lifetimes ago). BUT- there's also the forces that allow a siphon to work that is aiding into the gravitational constant. It's been a VERY long time since I took HS chemistry but I feel like there was something about weak ionic bonds that factored into that science.

    In this scenario, most of the controllables are controlled- the flow rate of the flush (1.6 GPF) and with the models being identical & the water trap bend being the same on both the 1st and 2nd floor, is there a "mechanical/hydraulic" advantage to the toilet on the 2nd floor or does the water trap bend act as a regulator?

    If it isn't mathematically significant (assuming that elevation poses a quantifiable, albeit minor, difference) at what elevation would the higher toilet be required to be at from the out pipe to take advantage of it's elevation given that all things are otherwise equal?

    Thanks in advance.

    -LD
     
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    #2
    200w (2).gif
     
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    #3
    Huskydriver said:
    View attachment 8564467
    Click to expand...
    We likely have different diets then- this is (seriously) a heavy math based question and likely above your pay grade but I wouldn't be at all surprised if we have enough intellectuals here that can answer the question. It's all good though- I don't know the answer either but I genuinely am interested if there is any merit to my question. Intellectually- I feel like elevation has to have some quantifiable factor in the efficiency of otherwise similar toilets.
     
    #10
    Your 1.6gal flush (total volume NOT rate) is equivalent to a slug of water less than 36" inches long in a 4" drain pipe, about 52" long in a 3" drain pipe. As water enters the toilet bowl and goes over the built in trap it will flow down the drain. If your basement drain is restricted and traps water then the second floor terlet will back up in the first floor terlet due to back pressure. The height advantage will be a disadvantage if the drain is clogged anywhere out to the street.
     
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    #11
    What he's saying is all the water and shit in the toilet have left the shitter long before you get any height advantage with your flush.

    Now, if there was a constant source of moving water in the shitter down pipe, then the venturi principle would affect exit speed of your defecated waste.
    But it doesn't, because it's an empty, static drain pipe.

    Now, if someone flushed a lower toilet a nanosecond before you flush the upper, you might get a suction advantage, but the vent would need to be compromised.






    In all of this, I think you are confusing outlet pressure of a column of liquid based on its height within a tube or tank.

    That's a different and simple discussion.
     
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    #16
    JoshPutman said:
    I always heard that all you need to know to be a plumber is that shit flows downhill and payday is on Friday.

    And you've been here long enough to know that putting a disclaimer in the title like "weirdos stay out" is going to make things ten times worse.

    View attachment 8564478
    Click to expand...
    Hah well I know we have plumbers and engineers here but thought hydrologists might be a reach even for this crowd... ;)
     
    #18
    Rocketvapor said:
    Your 1.6gal flush (total volume NOT rate) is equivalent to a slug of water less than 36" inches long in a 4" drain pipe, about 52" long in a 3" drain pipe. As water enters the toilet bowl and goes over the built in trap it will flow down the drain. If your basement drain is restricted and traps water then the second floor terlet will back up in the first floor terlet due to back pressure. The height advantage will be a disadvantage if the drain is clogged anywhere out to the street.
    Click to expand...
    This all sounds to be legit. So what you're saying is the trap itself doesn't 'regulate' the throughput but rather the lower floors would more or less 'equalize' the pressure keeping it consistent? Am I restating that correctly?
     
    #19
    Distance from the toilet flange to the vent is the only real important thing.

    I have 1 in my house that's about 8' away that never flushes well. I have another that's about 2' away from the stack and it will suck down anything.
     
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    #20
    Mike Casselton said:
    What he's saying is all the water and shit in the toilet have left the shitter long before you get any height advantage with your flush.

    Now, if there was a constant source of moving water in the shitter down pipe, then the venturi principle would affect exit speed of your defecated waste.
    But it doesn't, because it's an empty, static drain pipe.

    Now, if someone flushed a lower toilet a nanosecond before you flush the upper, you might get a suction advantage, but the vent would need to be compromised.






    In all of this, I think you are confusing outlet pressure of a column of liquid based on its height within a tube or tank.

    That's a different and simple discussion.
    Click to expand...
    So the length of pipe (what I was referring to as a height advantage or at least a competent of it) would be insignificant due to the speed in which the influx of water exits the "system" (for a lack of better terminology)?

    ETA: I'm looking up the Venturi Effect/Principle now, never heard of it before.
     
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    #24
    LuckyDuck said:
    So the length of pipe (what I was referring to as a height advantage or at least a competent of it) would be insignificant due to the speed in which the influx of water exits the "system" (for a lack of better terminology)?

    ETA: I'm looking up the Venturi Effect/Principle now, never heard of it before.
    Click to expand...
    Then you have obviously never worked on a carburetor
     
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    #25
    chevy_man said:
    Distance from the toilet flange to the vent is the only real important thing.

    I have 1 in my house that's about 8' away that never flushes well. I have another that's about 2' away from the stack and it will suck down anything.
    Click to expand...



    Could also be one of two simple problems;

    1. Somebody used two wax rings and closed out the diameter of the base of the toilet to the flange. It happens all the time. Makes a 3" hole into something closer to two inches.

    2. The water jet on the front of the toilet could be clogged up with debris of some sort.

    I once had a toilet that would only flush correctly here and there.
    One day I noticed something that looked like a piece of white plastic sticking out of the jet hole. Got a pair of pliers and pulled it out.
    Turned out to be the punch out piece from a gallon milk jug handle. I have to assume a child somehow placed it into the tank and it made it's way down to the jet.
     
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    #32
    jmp1 said:
    Dude....I've told you this before......If you ain't a fed then you are one weird mofo.












    My guess is still both..... carry on with your "research ".
    Click to expand...

    I may think differently and you're certainly welcome to your own opinion. Either way, I can live with being weird at least I'm learning things I didn't know before by asking questions. I fail to see how plumbing inquiries is a threat to your sovereignty though.
     
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    #35
    In my opinion:

    Your question supposes the pipe from the first and second floor toilet is a water column and when the toilet flushes the height of the water column adds to the suction.

    I think that's not how toilets work. Each toilet has a built in trap. Above the trap the water in the toilet. Below the toilet trap air all the to the sewer trap in the basement.

    This air gap makes any siphoning/suction impossible.

    So if one of the toilets is not working properly the problem is with that toilet, not it's location. If the sewer gets blocked then all toilets will stop working as the sewage backs up.
     
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    #37
    diverdon said:
    In my opinion:

    Your question supposes the pipe from the first and second floor toilet is a water column and when the toilet flushes the height of the water column adds to the suction.

    I think that's not how toilets work. Each toilet has a built in trap. Above the trap the water in the toilet. Below the toilet trap air all the to the sewer trap in the basement.

    This air gap makes any siphoning/suction impossible.

    So if one of the toilets is not working properly the problem is with that toilet, not it's location. If the sewer gets blocked then all toilets will stop working as the sewage backs up.
    Click to expand...
    That's a very accurate summation of what my assumption was. Fact remains that while it seemed plausible I assumed that there were more contributing factors that I likely hadn't accounted for (hence the question). But yes I theorized that the suction would be increased at the 2nd floor aided by the increase length of the pipes and gravity which based on the responses here sounds like that was an inaccurate guess.

    I'm ok with my guess being wrong, I figured there would be folks here that could/would give a straight answer either way and rather ask and know than be left in ignorant bliss wondering. But this has been a very interesting conversation for me reading other's inputs. One of those 'you don't know what you don't know' type of things.
     
    #41
    LuckyDuck said:
    Ok,

    I've got a serious question for the smart people here on the Hide...

    Let's say that given a 2 story house, there are 2 bathrooms/toliets on the 1st floor & 2 bathrooms/toliets on the 2nd floor. Let's also say that all of the toilets are exactly the same (aside from location/elevation) and that the sewer goes out in the basement directly beneath the 1st floor. So all toilets are the same make & model and since this is America in this scenario... let's call one of the constants that all of the toilets are rated at 1.6 GPF.

    So here's my question, and yes I'm being serious here (hence I why I said no weirdos and trying to recruit educated & experienced professionals here). As a layperson, I may be using the wrong terminology but would the 2 toilets on the 2nd floor have the equivalent of a "mechanical advantage" to that of the 2 toilets on the 1st floor of the house?

    Here's why I ask- I'd have to believe that a higher elevation from the sewer throughput would be able to take advantage of gravitational pull but, as we all learned in school, gravitational pull is constant (9.8 m/s^2 if I remember my schooling from lifetimes ago). BUT- there's also the forces that allow a siphon to work that is aiding into the gravitational constant. It's been a VERY long time since I took HS chemistry but I feel like there was something about weak ionic bonds that factored into that science.

    In this scenario, most of the controllables are controlled- the flow rate of the flush (1.6 GPF) and with the models being identical & the water trap bend being the same on both the 1st and 2nd floor, is there a "mechanical/hydraulic" advantage to the toilet on the 2nd floor or does the water trap bend act as a regulator?

    If it isn't mathematically significant (assuming that elevation poses a quantifiable, albeit minor, difference) at what elevation would the higher toilet be required to be at from the out pipe to take advantage of it's elevation given that all things are otherwise equal?

    Thanks in advance.

    -LD
    Click to expand...
    To answer your question "no"
    The height does not make any difference except that your poop will be moving faster down the drain at higher elevations.
     
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    #43
    Mike Casselton said:
    Could also be one of two simple problems;

    1. Somebody used two wax rings and closed out the diameter of the base of the toilet to the flange. It happens all the time. Makes a 3" hole into something closer to two inches.

    2. The water jet on the front of the toilet could be clogged up with debris of some sort.

    I once had a toilet that would only flush correctly here and there.
    One day I noticed something that looked like a piece of white plastic sticking out of the jet hole. Got a pair of pliers and pulled it out.
    Turned out to be the punch out piece from a gallon milk jug handle. I have to assume a child somehow placed it into the tank and it made it's way down to the jet.
    Click to expand...

    Plumber told me code is no more than 6' of pipe to vent.

    So until I have a large enough problem to chisel out concrete and add an extra vent, it stays that way.
     
    #44
    chevy_man said:
    Plumber told me code is no more than 6' of pipe to vent.

    So until I have a large enough problem to chisel out concrete and add an extra vent, it stays that way.
    Click to expand...

    I never said you should do anything about your vent.
    Shit, it's easy to check with a garden hose without damaging anything or tearing anything apart

    Look at the simple stuff first.


    Have you considered taking a peek at the wax ring.
    I've seen it cause your issue more times than I can count. 20 minutes, start to finish. If you're slow.
     
    #45
    Mike Casselton said:
    I never said you should do anything about your vent.
    Shit, it's easy to check with a garden hose without damaging anything or tearing anything apart

    Look at the simple stuff first.


    Have you considered taking a peek at the wax ring.
    I've seen it cause your issue more times than I can count. 20 minutes, start to finish. If you're slow.
    Click to expand...

    It's fine. I pulled it, scraped up the old ring, rebuilt the guts, and reset it. It's a vent issue.
     
    #46
    Check the vent at the top of the pipe. Sometimes birds, rats and squirrels will try to build a nest there. Since it's the toilet closest to the vent, it'll be affected more than one that has more vent volume to use.

    Hell, rent a plumbers bore scope and run it down the pipe if the first check doesn't show anything. It should save you from tearing or any unnecessary walls.


    Or, say fuck it, I'll flush twice. 😁
     
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    #50
    LuckyDuck said:
    Ok,

    I've got a serious question for the smart people here on the Hide...

    Let's say that given a 2 story house, there are 2 bathrooms/toliets on the 1st floor & 2 bathrooms/toliets on the 2nd floor. Let's also say that all of the toilets are exactly the same (aside from location/elevation) and that the sewer goes out in the basement directly beneath the 1st floor. So all toilets are the same make & model and since this is America in this scenario... let's call one of the constants that all of the toilets are rated at 1.6 GPF.

    So here's my question, and yes I'm being serious here (hence I why I said no weirdos and trying to recruit educated & experienced professionals here). As a layperson, I may be using the wrong terminology but would the 2 toilets on the 2nd floor have the equivalent of a "mechanical advantage" to that of the 2 toilets on the 1st floor of the house?

    Here's why I ask- I'd have to believe that a higher elevation from the sewer throughput would be able to take advantage of gravitational pull but, as we all learned in school, gravitational pull is constant (9.8 m/s^2 if I remember my schooling from lifetimes ago). BUT- there's also the forces that allow a siphon to work that is aiding into the gravitational constant. It's been a VERY long time since I took HS chemistry but I feel like there was something about weak ionic bonds that factored into that science.

    In this scenario, most of the controllables are controlled- the flow rate of the flush (1.6 GPF) and with the models being identical & the water trap bend being the same on both the 1st and 2nd floor, is there a "mechanical/hydraulic" advantage to the toilet on the 2nd floor or does the water trap bend act as a regulator?

    If it isn't mathematically significant (assuming that elevation poses a quantifiable, albeit minor, difference) at what elevation would the higher toilet be required to be at from the out pipe to take advantage of it's elevation given that all things are otherwise equal?

    Thanks in advance.

    -LD
    Click to expand...
    Do you have an actual problem or are you just being an askhole?
     
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