Threading 3" pipe, anybody have experience with that ?

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I`m a maintenance engineer for a oil&gas company nowI have a job coming up to replace the sprinkler piping in the accomodation of an offshore platformAll the piping is threaded galvanised pipe, but it`s from 1985 and starting to rot (seawater in the pipes...)Piping to the sprinklers is 1", easy to replace thatBut the header is 3" threaded pipeWhen I was a pipefitter, I remember a job 15 years ago, where I was installing a lot of 3" threaded pipeIn my memory it was a nightmare, heavy fittings, hard to assemble, and we needed 36" and 48" pipe wrenches to get it tight enoughWhat`s your thought and experience on threading 3" pipe and assembling it ?My alternative is to fabricate the header out of 3" pipe with welded fittings and flanges, and hot-dip galvanise it afterwards
Reply:Sprinkler pipe of that size is all roll groove these days. Like Victaulic or Sprink.
Reply:If you must thread it, use Loctite 577 Hi Pressure Pipe Sealant. It will seal the joint even if it's not done up hard.
Reply:

Originally Posted by Woznme

If you must thread it, use Loctite 577 Hi Pressure Pipe Sealant. It will seal the joint even if it's not done up hard.
Reply:I threaded some 3” as a older teenager you definitely need a low iq muscle head for that job. back then i fit that discription As for tightening you will need at at 36” wrenches and will have a few leaks even 48” wrenches we will end up with a seepage here and there if you can change to bolted flange or those other ones someone up above mentioned it makes fixing problems a lot easier. I push 250 psi thru a couple of  victaulic fittings seem to hold up wellDo not argue with an idiot. He will drag you down to his level and beat you with experience.
Reply:victaulic fittings are the way to go IMO, welding and flanges would be great for smaller sections but if speccing a full system victaulic will be cheaper.Murphy's Golden Rule: Whoever has the gold, makes the rules.
Reply:The make electric hand thread machines.I have use lathes and single point the thread. But a had very large lathes.Dave

Originally Posted by bluemoon

I`m a maintenance engineer for a oil&gas company nowI have a job coming up to replace the sprinkler piping in the accomodation of an offshore platformAll the piping is threaded galvanised pipe, but it`s from 1985 and starting to rot (seawater in the pipes...)Piping to the sprinklers is 1", easy to replace thatBut the header is 3" threaded pipeWhen I was a pipefitter, I remember a job 15 years ago, where I was installing a lot of 3" threaded pipeIn my memory it was a nightmare, heavy fittings, hard to assemble, and we needed 36" and 48" pipe wrenches to get it tight enoughWhat`s your thought and experience on threading 3" pipe and assembling it ?My alternative is to fabricate the header out of 3" pipe with welded fittings and flanges, and hot-dip galvanise it afterwards
Reply:If I remember right rigid makes a adapter to thread 3 and 4 inch for thier machines but keep good dies in them lots of good cutting oil no cheap stuff you will find the galvanized loads up in the dies with cheap oil you will also find cutting the galvanized a lot easier with a band saw with cutting lubricant because the galvanized will plug up the teeth . If you use a rigid oiler one that catches the oil and reuses the cutting oil KEEP it clean that galvanized will get in the oiler and oiler won’t work !
Reply:The standard portable powered die driver goes on a orbital threader for doing the larger sizes. Nothing to it other than it is a little heavier piece.
Reply:I agree, the size is not a big deal.www.urkafarms.com
Reply:

Originally Posted by idacal

I threaded some 3” as a older teenager you definitely need a low iq muscle head for that job. back then i fit that discription As for tightening you will need at at 36” wrenches and will have a few leaks even 48” wrenches we will end up with a seepage here and there if you can change to bolted flange or those other ones someone up above mentioned it makes fixing problems a lot easier. I push 250 psi thru a couple of  victaulic fittings seem to hold up well
Reply:

Originally Posted by danielplace

The standard portable powered die driver goes on a orbital threader for doing the larger sizes. Nothing to it other than it is a little heavier piece.
Reply:blue,no one has mentioned LOKRING so I'll go ahead and suggest you consider that fitting system for the 3" pipe in your water flood mains.This system beats a butt weld & is so fast to install it's actually depressing for pipe welders who see it the first time!  Works using the plastic deformation of steel pipe wall to the annular raised profile 'ring' inside the fitting. Worth a look? likely not in your pipe spec (yet) but for joining pressure pipe small up to 3" - even up to XX wall- its a great system.I installed hundreds of feet of 3" on off shore platforms in the Cook Inlet in AK USA, and a crew of three welders couldn't even keep up just mounting and hanging those lines we installed. The fluids were hydrocarbons and water mixed and the cost of our install was 1/4 that of welded pipe in spools.  We installed and pressure tested the entire run in a couple of 12 hours shifts- there were entire stretches where the pipe was still hung by ropes! because the welders building mounts were a week or longer behind the pipe install. So we pressure tested all the joints to ANSI 300 for 3" in order to help the client production company become more comfortable with the fitting system.  Needless to say a 1,000 PSI hydro test for what would be good at 300 PSI showed what the fitting system could do!The pipe ends are cut and dressed w hand tools to length- a gauging tool confirms tolerances; then slip on a fitting- use the hydraulic compression tool to slide the 'lokring' and you're done. Typical sched. 40 steel pipe joint is 10-15 minutes with one man and half that with two.cheers,Kevin MorinKenai, AK
Reply:I've used lokring for years on refrigeration copper up to 1-5/8" on long runs and roof space work that's a fire hazard. Didn't know they had a system for steel pipe. It should be ideal for water.
Reply:Victaulic may have a fitting called a roust-a-bout, they don't require the groove, the clamps have opposing carbide pucks that bite into the OD of the pipe, they use the same type of gasketing, I used them on a low pressure steam line job in 1984 or early 85, easy to work with & a solid solution, just have to have the alignment close. I don't know if they still make them though.NRA LIFE MEMBERUNITWELD 175 AMP 3 IN1 DCMIDSTATES 300 AMP AC MACHINELET'S GO BRANDON!"Those who would give up essential Liberty, to purchase a little temporary Safety, deserve neither Liberty nor Safety.” BENJAMIN FRANKLIN
Reply:I've threaded a lot of 3", 4" and 6" conduit.  Get one of these...  You'll also need a pony, and pipe stand and a couple of big chain wrenches.

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