Predictions? I will go with 1500 lbs
PVC drop pipe: male adapters vs threading the pipe
- Thread starter Paltus
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VAWellDriller
Active Member
I pulled on 4.5" well casing glued together one time with #15000 and it didn't budge.
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Paltus
Member
So how do I translate that into how much I should torque the pipe together. That's what I am after.
The pump will probably be sub-1 hp.
I don't think the answer should depend on the pump size. It should depend on material ( PVC sch 80 ) and pipe size ( 1" )
thanks much for your other points.
Gonna measure torque on a pipe wrench? Yes, it could be done, but it is not common.
https://www.lascofittings.com/threads says "The right way to assemble a threaded PVC joint-Schedule 40 or 80 is finger tight plus one to two turns-no more." So maybe go with finger tight plus 1.5 turns or hand tight plus 1.
Paltus
Member
I am curious which end will fail first, and how, too -- the glued male adapter or the threaded PVC pipe ...
Any bets ? The test pipe is curing now but it looks like the test may extend into the next week. Tried threading
PVC today with electric threader and the threads look crappy. The ones where I reversed many times
look almost stripped. The best one so far is from electric threading forward in one pass, then unscrewing
the pipe from the die backwards by hand, little by little back and forth. Still looks crappy comparing to factory made male adapter though.
Not only factory made male adapter threads look better, they are quite a bit thicker also.
The ID of the adapter is smaller than the pipe and the thread is higher
The glued joint is a question mark of course.
Paltus
Member
I'd be fine with this spec for above ground outdoor irrigation or some such but I am not sure why
there is no more accurate spec for a well drop pipe in 2021. Its an expensive and pretty inconvenient failure potentially.
Paltus
Member
BTW there is a torque table on page 101 of http://pdf.lowes.com/productdocuments/11f47356-6978-439e-89c6-2a4ca885d60e/01158459.pdf
but it is for CPVC, not PVC, and 7 ft lbs feels like not enough for a drop pipe
I was inexperienced several years ago as you are and was nervous about properly torquing the threaded schedule 80 1" PVC pipe with stainless couplings on my 100' drop pipe. Cary instructed me at the time to tighten until it "pops" as he has in this thread. I was unsure. Assembled the first joint dry and when it felt like it was getting tight enough it will almost want to stop turning, and then audibly pop as it turns slightly more. I may have popped it twice because I always over tighten things (causes many problems for me 
).
We can sit here on the computer and discuss torque for pvc joints but my opinion is unless you are tightening larger than 2" pvc, just get outside and do it. You will find quickly it's pretty simple. I think it will pop no matter your location, elevation, what you ate for breakfast.
).We can sit here on the computer and discuss torque for pvc joints but my opinion is unless you are tightening larger than 2" pvc, just get outside and do it. You will find quickly it's pretty simple. I think it will pop no matter your location, elevation, what you ate for breakfast.
That is what I like about running it dry. Shouldn't have to take it apart but maybe once every 20-30 years. Even then it will still come unscrewed with some elbow grease.
Paltus
Member
I was inexperienced several years ago as you are and was nervous about properly torquing the threaded schedule 80 1" PVC pipe with stainless couplings on my 100' drop pipe. Cary instructed me at the time to tighten until it "pops" as he has in this thread. I was unsure. Assembled the first joint dry and when it felt like it was getting tight enough it will almost want to stop turning, and then audibly pop as it turns slightly more. I may have popped it twice because I always over tighten things (causes many problems for me
We can sit here on the computer and discuss torque for pvc joints but my opinion is unless you are tightening larger than 2" pvc, just get outside and do it. You will find quickly it's pretty simple. I think it will pop no matter your location, elevation, what you ate for breakfast.
I can pull 75' pump & pvc pipe from a well by hand. Its a bit heavy but manageable. So I'd not worry about 100' too much neither.
In the 75' well, it is hanging on sch 40 pvc, for many years, so that range depth gotta be pretty forgiving.
It doesnt feel like I can pull 280', that feels too heavy.
I think I can't pull 200' neither so I am worried.
The job will be in October sometime or later in the year so I have time to prepare which I am doing.
You are intending to use 10 ft schedule 80 pvc. You intend to lift maybe 11 ft, and somehow clamp the pipe, perhaps with a tool such as on https://www.deanbennettsupply.com/installation-tools.html
See if these inspire you:
If you do use polyethylene, use an extra-long barb on top, which accepts 3 worm-gear clamps.
Paltus
Member
thanks. I will be lowering first, the 200' well is undeveloped. Pulling I'll have to do if something goes wrong ( hopefully not but .. )
I'm planning to clamp with pipe vise below glued on male adapters
and tie a ladder to a truck to help support 10' pipe sections going in.
BTW I just had this thought. Why not put a couple self tapping SS screws through each adapter & pipe to help
prevent glue joint failure. Even if they leak a little, so what. Threaded joints without sealant might leak a little also.
VAWellDriller
Active Member
The answer DOES depend on the pump size.....it depends on the motor size....HA HA. If you're worried about something coming unscrewed; you need to base that on what force is making the torque; and that force is the motor start and stop.
Pull a 24" wrench with 5 lbs on the end on the handle: pull a 12" wrench with 10 lbs on the end. Like mentioned below, you're overthinking this; just do it; this scale is so small it will be pretty obvious when you go to do it. If you use glue on fittings they will likely bottom out. You can overtighten with metal couplings, I'm pretty sure the integral bell end pipe I use bottoms out.
VAWellDriller
Active Member
Since NPT won't fully seal on its own, a little silt and grit and anything in the water will find its way in the threads. I've twisted pipe off and broken some SCH80 that was put together dry and was in for a long time. Maybe it was old and brittle, but I find the extra few seconds for a dab of dope worthwhile.
Paltus
Member
No I don't think like that - when I am following BMW spec for torquing bolts on my car I know that if I undertorque they might unscrew or wont work and if I overtorque they might break or strip the threads etc .
similarly 1" sch80 PVC has to have optimal torquing force. If a pump is bigger than that, it just cant be used with sch80 PVC then period. And for all pumps that are smaller, the pvc should be torqued to that same optimal value, not values that match various pump sizes.
You are right I might be over-thinking it but I am surprised there is no numeric torque standard for 1" sch80 pvc in the industry.
wwhitney
In the Trades
Not necessarily. It's possible that the manufacturing tolerances on each side of the joint are large enough that the optimal torque for any particular joint varies. And that over many different joints (of the same size), the optimal value varies over a large range. I.e. torque may not be a suitable acceptance criterion.
Cheers, Wayne
Paltus
Member
sure, there is a range: between 1 pop and 2 pop. I'd be happy with a range also as long as it is in the units my torque wrench would understand
Measure the torque between the first and second pop. Perfect! Lol.
VAWellDriller
Active Member
This isn't a BMW so that manual does not apply. You asked if there was an industry standard to prevent pipe unscrewing in submersible pump installations. There IS and I quoted that standard. Franklin electric that invented submersible motors and sells millions of pumps and motors has published that spec in their AIM manual for decades.
NAPCO that makes threaded pvc drop pipe says 1" will handle up to 1.5HP AND 1.25" will handle up to 2HP. They say use dope NOT tape and torque to hand tight plus 1 full turn.
I'll admit that's not very scientific so I shoot for the published specs I know to work.
Paltus
Member
I will measure it in ft/lbs for PVC+SS dry, for factory threads on the adapter and for DIY threads on the other end of my test pipe,
and will post it
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