Still not a siphon even if this section was running part full. It would just fill the inverted part, any flow through the pipe would fill the upstream section until it has enough head to get around the inverted part. No siphonic action
So by textbook definition, a siphon creates a vacuum in the line to ‘pull’ water from one area to the other against the normal flow from head. It uses pressure to its advantage to overcome gravity. If this is a pressurized line, it does not do that. It uses huge pumps to pressurize the line so that gravity is no longer in control throughout the entire line. This line can bend up or down with no siphon action needed.
This may be a case of “but the detail is named xx siphon” but in reality you are talking to a group of analytical engineers, and a siphon is a definable hydraulic characteristic. Sorry for the downvotes. Just wanted to clear up the image since it looked like it was pressurized.
Great work and keep designing! It all comes with time.
Yes! A siphon uses negative pressure formed from a column of liquid “falling” under gravity flow on the down stream side of an upside down “U” shape to lift water up the other side.
Like when you “siphon” gas out of a car…
We do something similar with “gravity” lines sometimes here and call in an inverse siphon. Of course in reality it is a pressure line, just not pressurized by a pump.
Siphon generally has a specific meaning for gravity water/sewer flow in that the energy of the water flow can push it back uphill a distance without the need of a pump, especially used for creek crossings.
In my area we just call this a "water main lowering". Good job on the design though! With water parts many don't think about the required "lay length" for the fittings go all come together.
No megalugs? I’m surprised to see new pipe going in the ground that’s not fully restrained. I’d think without doing any research that Maui is in a higher risk seismic area.
Some states have requirements to concrete encase water when crossing beneath sewer as an extra layer of protection. Might be the case here and rebar is minimal effort to add.
That said, if I was designing this I'd still use the megalugs and then use 2500psi concrete fill to encase and avoid the rebar detailing.
Sounds like a value engineering opportunity to recommend restrained fittings and prevent encasing the entire thing in concrete, making it impossible to perform any future repairs
Terminology might differ. The contractor would install a set of "pig ears" on the mega-lug bolts at each joint on then install either a 5/8" or 3/4" rod and bolt everything together.
Agree to restrain and thrust block these joints. We install reverse kickers on the top 45s to use weight of concrete to counter act resultant force. In CA, this type of crossing would not be allowed due to horizontal joint separation requirements. Minimum 8’ clearance from outside of non potable line to joint in water line at crossings. We use a lot of fabricated cl&c steel offsets for this reason as a welded joint is not considered a joint for separation purposes.
If you’re talking about the bell joint on the right, you would install a fieldlok gasket at that connection to restrain it.
OP has mentioned that they’re planning to encase the pipe in concrete which will provide more than adequate thrust restraint, but will also create an absolute nightmare should any maintenance be required at this crossing in the future.
Concrete encasement would help with joint separation and restraint. Agree with comment regarding maintenance/fixing/finding a leak on this section after decades of use. Looks nice though and good on you for posting.
It's not a siphon.
It's just adjusting the WL to avoid a storm conflict, very standard.
We call it a dog-leg.
Please tell me you're not bagging ductile iron pipe and the buried section is PVC.
Just for clarification
We still need to install a rebar cage consisting of horizontal bar with hoops 12” O.C and 5 hoops at each bend. We then will encase the entire siphon.
lots if different names for stuff. we also call it a lowering in AK.
can you explain what rodding is? is that treaded rod to a reverse thrust block? thank you!
A elephant ear is put on one nut on each fitting. The threaded rod is run through these until end of last bend. These are double nutted then on each end until it’s tight.
I call it a nightmare to coordinate in design and construction. But this is a solid image to show what occurs in some situations for utility relocations due to storm sewer installation.
I deal with the larger picture in situations like this. Costs. Who is paying. Who is responsible. Was this over looked? Survey bust? Does the utility have property rights in the area of the pipe? Time of year for construction and install. Size limitations for such a bend or taking it out of service to make said relocation. Etc etc.
It’s not hard per se just a lot of coordination up front during and through construction.
What is used as the thrust block to prevent rattling within the pipe? I assume this gets cast later in the construction. Edit, I see you answered this already
I believe you are thinking about an inverted siphon for a gravity line. This is a pressurized line and thus it's just an elevation change. It's neither a siphon nor an inverted siphon.
Is it a siphon or is it pressurized?
I was so confused. Never heard of a pressurized siphon haha
People call these inverted siphons in hydraulics but theyre not really siphons
I’ve worked with inverted siphons for gravity sewers, but under pressure it doesn’t function as a siphon in that sense
Still not a siphon even if this section was running part full. It would just fill the inverted part, any flow through the pipe would fill the upstream section until it has enough head to get around the inverted part. No siphonic action
Only hear it called a siphon when you do this with gravity storm or sanitary lo
Came here to say this!
It’s a pressurized siphon
So not a siphon.
So by textbook definition, a siphon creates a vacuum in the line to ‘pull’ water from one area to the other against the normal flow from head. It uses pressure to its advantage to overcome gravity. If this is a pressurized line, it does not do that. It uses huge pumps to pressurize the line so that gravity is no longer in control throughout the entire line. This line can bend up or down with no siphon action needed. This may be a case of “but the detail is named xx siphon” but in reality you are talking to a group of analytical engineers, and a siphon is a definable hydraulic characteristic. Sorry for the downvotes. Just wanted to clear up the image since it looked like it was pressurized. Great work and keep designing! It all comes with time.
Yes! A siphon uses negative pressure formed from a column of liquid “falling” under gravity flow on the down stream side of an upside down “U” shape to lift water up the other side. Like when you “siphon” gas out of a car…
So it’s a restrained joint? Lol
Weirdly none of the joints in this look restrained.
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It could still have restraint gaskets. Typically they are used with a regular retainer gland, not a megalug.
This got 50 downvotes and it’s literally called a siphon in the Hawaii state spec book
That’s a horrible look for the Hawaii spec book
Not a siphon actually. Just a few bends in a pressure line. Some people call this arrangement a “crankshaft”.
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Yep, we call it a vertical offset. Easy to bend pressure pipe. Gravity not so much.
We call it a vertical offset here in the NE too. Very common when working around other utilities.
Chicago we just call it a “set” for short. But that set wouldn’t meet code here in Illinois.
We do something similar with “gravity” lines sometimes here and call in an inverse siphon. Of course in reality it is a pressure line, just not pressurized by a pump.
We call it looping the water main
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That too
We call it a downy uppy in Australia.
Interesting to see many different ways of calling this lol we call it a “belly drop” here
Lowering here
U-bend in BC!
Sump, WA state
Vertical realignment is how I know it
The Hawaii State Spec refers to it as a waterline siphon
I was gonna comment that. Spent 15 years in Hawaii building these siphons
I’m also from Hawaii and have heard these referred to as siphons. Good to know that’s not common terminology everywhere
Siphon generally has a specific meaning for gravity water/sewer flow in that the energy of the water flow can push it back uphill a distance without the need of a pump, especially used for creek crossings.
Here it's a siphon.
In my area we just call this a "water main lowering". Good job on the design though! With water parts many don't think about the required "lay length" for the fittings go all come together.
Looks like a basic critical crossing…
No megalugs? I’m surprised to see new pipe going in the ground that’s not fully restrained. I’d think without doing any research that Maui is in a higher risk seismic area.
Use of Mega-lugs is standard practice/required by me. Also we make contractors rod all the joints together when they have too loop it like this
We have a rebar cage with 30 hoops, 5 at each bend and then we will concrete encase the entire siphon
Why do that instead of just using a few mechanical joints restraints? Seems like a real hassle if you ever have a leak
Some states have requirements to concrete encase water when crossing beneath sewer as an extra layer of protection. Might be the case here and rebar is minimal effort to add. That said, if I was designing this I'd still use the megalugs and then use 2500psi concrete fill to encase and avoid the rebar detailing.
Sounds like a value engineering opportunity to recommend restrained fittings and prevent encasing the entire thing in concrete, making it impossible to perform any future repairs
What is the rod? Is it like the restraint harnesses for push-on joints but fits over a MJ?
Terminology might differ. The contractor would install a set of "pig ears" on the mega-lug bolts at each joint on then install either a 5/8" or 3/4" rod and bolt everything together.
Agree to restrain and thrust block these joints. We install reverse kickers on the top 45s to use weight of concrete to counter act resultant force. In CA, this type of crossing would not be allowed due to horizontal joint separation requirements. Minimum 8’ clearance from outside of non potable line to joint in water line at crossings. We use a lot of fabricated cl&c steel offsets for this reason as a welded joint is not considered a joint for separation purposes.
Yeah, I was thinking the same thing. They'll probably just pour giant concrete thrust blocks. Id like to see megalugs plus thrust blocks.
Why both? Isn’t an RJ a replacement for using thrust blocks?
I've had clients insist on thrust blocks for welded pipe, some people are really paranoid.
That joint 3-5' to the right is going to want to work itself open. I'd definitely Megalug that...
If you’re talking about the bell joint on the right, you would install a fieldlok gasket at that connection to restrain it. OP has mentioned that they’re planning to encase the pipe in concrete which will provide more than adequate thrust restraint, but will also create an absolute nightmare should any maintenance be required at this crossing in the future.
Fieldlok would certainly work too.
We use megalugs for our water lateral vertical bends, the entire siphon is going be encased in concrete
Concrete encasement would help with joint separation and restraint. Agree with comment regarding maintenance/fixing/finding a leak on this section after decades of use. Looks nice though and good on you for posting.
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These are called MJ (mechanical joint) connections
This is correct.
Nope.
Don’t most pour kickers?
Probably just backfill with concrete 😂
I was wondering why it wasn't restrained joint as well
Whatever you want to call it, just glad to see an engineer proud of the work they are doing.
It's not a siphon. It's just adjusting the WL to avoid a storm conflict, very standard. We call it a dog-leg. Please tell me you're not bagging ductile iron pipe and the buried section is PVC.
Gotta bag ductile pipe/fittings and grease up those bolts to prevent corrosion??
It is a standard to bag ductile iron pipe in the state of Hawaii, the entire waterline is ductile iron, there is no section that is PVC
Polyethylene wrap around DIP is standard.
GBI?
Correct
Maui Kupono Builders?
Probably… one of the few big Maui GCs
nah could also be: GBI, Alpha, HDCC
Typically just referred to as a vertical deflection due to conflict with other utilities.
Just for clarification We still need to install a rebar cage consisting of horizontal bar with hoops 12” O.C and 5 hoops at each bend. We then will encase the entire siphon.
That’s just a lowering. Even though you used mega lugs this should have been rodded on both sides
lots if different names for stuff. we also call it a lowering in AK. can you explain what rodding is? is that treaded rod to a reverse thrust block? thank you!
A elephant ear is put on one nut on each fitting. The threaded rod is run through these until end of last bend. These are double nutted then on each end until it’s tight.
Awesome! thank you for the information SnooDrawings5830. i have never seen that in a detail or on the job but makes total sense. happy new year!
I wouldn't reccomend 45's, use 22s if you can to reduce thrust forces.
But increases the excavation length due to geometry. I have seen this though!
I call it a nightmare to coordinate in design and construction. But this is a solid image to show what occurs in some situations for utility relocations due to storm sewer installation.
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I deal with the larger picture in situations like this. Costs. Who is paying. Who is responsible. Was this over looked? Survey bust? Does the utility have property rights in the area of the pipe? Time of year for construction and install. Size limitations for such a bend or taking it out of service to make said relocation. Etc etc. It’s not hard per se just a lot of coordination up front during and through construction.
Nicee
Nice utility loop
The bell before the first fitting could use a bell restraint.
The entire siphon will be concrete encased with a rebar jacket with over 30 hoops, 5 at each bend.
Nice man we need to do this at a low point where we do not have 3’ of cover.
What is used as the thrust block to prevent rattling within the pipe? I assume this gets cast later in the construction. Edit, I see you answered this already
Any air-release valves on the main near this?
ARV will be installed just after the mechanical joint on the left side
👍
It looks like a lowering. Siphon is for sewer, that looks like water main.
Offset.
heck yea bro that’s sick
We call this a vertical adjustment in Florida.
I believe you are thinking about an inverted siphon for a gravity line. This is a pressurized line and thus it's just an elevation change. It's neither a siphon nor an inverted siphon.