Potable water pipe connections
Potable water pipe connections
(OP)
I've volunteered to work on a small, water distribution project in the Dominican Republic which will benefit the local community. One of the first goals is to install roughly 3000 feet of 4" pipe from a well to an open tank. Maximum pressure expected is only about 70 psi. The pipe will be steel, ductile iron is being proposed. I suspect galvanized steel or black iron may be considered as well. The pipe will be buried.
I'm very familiar with welded, flanged and other forms of pipe construction but I'm being told there's another, more simple method that might use some sort of mechanical joint similar to a Fernco coupling, but I gather these Fernco couplings are only intended for low pressure lines (less than 5 psi).
https://www.fernco.com/
Unfortunately, the dozen or so engineers who have volunteered for this work are not piping experts and my background is primarily industrial piping and I've never heard of anything like this kind of piping connection system.
Is there any other method of connecting steel piping for use at up to ~ 100 psi?
If there is no easy way to connect lengths of pipe, would PVC be a suitable solution?
I'm very familiar with welded, flanged and other forms of pipe construction but I'm being told there's another, more simple method that might use some sort of mechanical joint similar to a Fernco coupling, but I gather these Fernco couplings are only intended for low pressure lines (less than 5 psi).
https://www.fernco.com/
Unfortunately, the dozen or so engineers who have volunteered for this work are not piping experts and my background is primarily industrial piping and I've never heard of anything like this kind of piping connection system.
Is there any other method of connecting steel piping for use at up to ~ 100 psi?
If there is no easy way to connect lengths of pipe, would PVC be a suitable solution?





RE: Potable water pipe connections
You will likely not be able to find acceptable (forget qualified) welders to keep the pipes sanitary. Threaded connections with a few unions to make up the joints is likely the best bet. PLastic and its glued joints? Maybe - but I don't know how easily a 4 inch diameter long run of pipe will stand up.
Height difference from end to end? Any hills or slopes in the middle?
RE: Potable water pipe connections
Not sure about skilled labor yet. I suspect it won't be there so I feel there's a potential we end up going with PVC.
I wouldn't dismiss the idea of screwed fittings but this is fairly large diameter pipe for screwed fittings and it would also take some skill and effort to make the threads and rotate a 200 pound pipe.
RE: Potable water pipe connections
Call them to discuss the best and cheapest option if you want to go that way.
Some of these are end loading capable, but others may need thrust blocks.
At $" or 100mm for PE pipe, you can usually get long lengths ( 180+ m) reeled which means you only have a few joints to worry about.
PE is very flexible and forgiving long term to being dropped into a rocky trench.
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
RE: Potable water pipe connections
RE: Potable water pipe connections
http://www.google.com/url?sa=t&rct=j&q=&am...
http://ameind.com/expresseng/img/files/DRESSER_PIP...
RE: Potable water pipe connections
RE: Potable water pipe connections
http://www.pipingguide.net/2013/02/joingin-ductile...
Restrained fittings are used at changes of direction. Thrust blocks are an outdated design and should not be used.
PVC pipe is another option. PVC pipe is assembled in the same fashion with bell and spigot joints.
RE: Potable water pipe connections
David Simpson, PE
MuleShoe Engineering
In questions of science, the authority of a thousand is not worth the humble reasoning of a single individual. Galileo Galilei, Italian Physicist
RE: Potable water pipe connections
In most cases here I would agree with you, but the OP is talking about ductile Iron. There are millions of miles of ductile Iron pipe used in the water supply industry which last a lot longer than 20 years.
Also I usually reckon on max size of PE which can be reeled in long lengths as 180mm OD. So 4" approx. should be available on a reel. This means you can install it like a plough.
I don't think the Dominican Republic is going to import what is probably the best technological solution for a small water project though....
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
RE: Potable water pipe connections
I've seen HDPE SDR 13.5 in 4-inch spools, but limited to 766 ft. Nothing thinner.
David Simpson, PE
MuleShoe Engineering
In questions of science, the authority of a thousand is not worth the humble reasoning of a single individual. Galileo Galilei, Italian Physicist
RE: Potable water pipe connections
victaulic and dresser are not recommended below grade
Fernco is not recommended at all
threaded and flanged not recommended below grade
welded, no skilled labor to do it
glued pvc or bell and spigot are easy.
fused PE pipe requires skilled labor and equipment, but there would only be a few joints
schedule 40 pvc can use glued joints
AWWA C900 pvc uses bell and spigot joints
both are easy to joint but the bedding and compaction requirements are strict. installed properly, the life of buried pvc should be way more than 5 years.
ductile iron bell and spigot is also easy to assemble, although a lot heavier to lift. bedding and compaction requirements are much less strict for ductile. life should approach 100-years
PE pipe (drisco) can be assembled with minimal joints, bedding and compaction is not terribly difficult, but you will probably want to fuse the joints. there should not be many joints. buried would have a good lifetime, above ground would be susceptible to vandalism and damage.
i would stay away from galvanized steel or black iron - totally unsuitable for your particular application.
cement mortar lined and coated steel pipe would be good if the corrosion potential is low, however this takes considerable expertise to install and is very heavy. properly done would last easily 50 years. I am not convinced you could source this in the DR.
RE: Potable water pipe connections
~
bimr, interesting about the blocks. The discussion so far has been to use them. No mention of "restrained fittings" - can you explain what you mean by that?
~
zdas, thanks for the info. The longevity of the system is obviously important as is low maintenance. Do you have links to any studies that compare longevity? That would be very helpful in convincing others on the team the best direction to go.
Dropping a spool of HDPE or FRP sounds perfect but I have to believe the spool is going to be enormous and require a specialized truck to haul it and lay it. That said, I'll certainly follow up on all leads.
Regarding cathodic protection, I take it that's required for steel pipe. Any additional leads on that would be appreciated. As mentioned, my piping expertise is generally high pressure industry piping, not potable water nor underground so I'm groping a bit for what might be important here as well.
Thanks again for all the input.
Dave.
RE: Potable water pipe connections
RE: Potable water pipe connections
David Simpson, PE
MuleShoe Engineering
In questions of science, the authority of a thousand is not worth the humble reasoning of a single individual. Galileo Galilei, Italian Physicist
RE: Potable water pipe connections
Internally ribbed features in the couplings engage the grooves to provide restraint.
It is therefore a 'restrained coupling', in that it is very difficult to separate with axial force once assembled.
There is a rubber seal adjacent/inboard of the groove.
In the DR, I'd worry about scratching of the pipe surface and contamination with dirt making the seal leak, and also availability of the tooling and skill for prepping the pipe ends.
Victaulic stuff is popular in sprinkler piping.
A Dresser coupling is vaguely similar to a Victaulic, except that it's much, much lighter duty and requires no special end prep of the pipe.
The axial restraint is provided by a thin metal toothed sleeve, over the rubber seal, that bites into the pipe OD.
The axial restraint is _optional_; not all Dresser couplings have it, so not all are 'restrained', and even the restrained ones are not in the same class with the Victaulic.
I wouldn't use either one underground, not least because they both use a small number of tangential bolts to secure the joint. Unlike pipe flanges, corrosion/ failure of any one of the bolts would compromise the joint's integrity.
Mike Halloran
Pembroke Pines, FL, USA
RE: Potable water pipe connections
I'd stay away from ferrous materials - more corrosion prone, heavier, harder to install. Likewise, fusing HDPE takes experience to be successful.
I have no experience with FRP, but I generally respect zdas04's opinion. That might be worth checking out.
RE: Potable water pipe connections
I have never been to the DR, and I know that every island is a unique ecosystem, I have worked on other Caribbean Islands and all the digging was either in volcanic soil or coral, either one would be quite abrasive.
David Simpson, PE
MuleShoe Engineering
In questions of science, the authority of a thousand is not worth the humble reasoning of a single individual. Galileo Galilei, Italian Physicist
RE: Potable water pipe connections
For buried service, sliding couplings need not be harnessed if there is a sufficient length of pipe on both sides for soil friction to resist the thrust.
For ductile iron pipe, push-on and mechanical joints are the most commonly used for buried service. These joints allow for some pipe deflection (about to 5 degrees depending on pipe size) without sacrificing watertightness. Except in certain unstable soil buried joints are not required to support the weight of the pipe.
Restrained joints such as a bolted flange are not used underground unless needed to restrain thrust at a change in direction.
It is extremely rare in the municipal business to provide cathodic protection on a pipe.
Ductile iron is installed in a plastic bag. Ductile iron and PVC will have a service life of 50-100 years when installed properly and buried.
http://www.mrwa.com/WaterWorksMnl/Chapter%2021%20D...
RE: Potable water pipe connections
RE: Potable water pipe connections
David Simpson, PE
MuleShoe Engineering
In questions of science, the authority of a thousand is not worth the humble reasoning of a single individual. Galileo Galilei, Italian Physicist
RE: Potable water pipe connections
From another brochure of theirs a 110mm (equivalent to 4") is a reel 2.5m in internal, diameter, 3.1m external diameter, 570mm wide and weighs 206 kg. A fair size, but with enough men and women can be handled. For 3000 ft ~900m) this is only 9 joints. Just use an electo coupling which works off a car battery. I'm fairly sure you can get it in larger lengths and just tow it behind a 4 x 4 on a cable drum puller. something like this http://www.globalpipe.de/news-redefining-installat...
I endorse zdas04s concern over GRP and PVC. Great stuff in the right environment, but underground pipelines isn't it.
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
RE: Potable water pipe connections
It is the preferred material for potable water distribution and sanitary sewer collection piping in the southeast US and in general throughout the US.
There are sometimes reasons to use other kinds of piping, but I think that more than 90% of the pipe I've specified is PVC.
I've looked into PVC use in the US and it appears to have a long lifespan when installed correctly.
RE: Potable water pipe connections
A word of warning. Make sure you have done your homework on the design flow rate and let me know. We dont want too much friction loss for the 3000 foot length. The well pumps might over-pressurise the 110 line. Keep in touch and let me know what the flow rate and terrain profile looks like, or if you need help with a possible pipe material donor in DR.
RE: Potable water pipe connections
The few welds You need can do with the very easy electroweld system.
It's just great.
RE: Potable water pipe connections
This technology would only work with steel lines, I am not sure if it has been used with black or ductile iron.