Welding Pipe

bob_50

on the specs. In my experience most specs call for anything over 2" to be welded unless it's a Vic job. bob

RonL

Welding Pipe

Does anyone still thread 3 and 4 inch pipe? If so, why? I know this is a hot topic and people have emotional attachment to the way they do things, but what is the reasons behind doing it the way you do? Studies?
I would think that with all the advancements in welding technology that welding pipe would be more common than it is. Any reason to not weld?

Jeff Elston

pipe

I use gruvlok at at those sizes, anyway who wants to weld? just kidding welding has its place I just havent needed to!

Blackoakbob

weld vs. threaded....

I do both but welding under special circumstances. If absolutely necessary, in a customers building with all safety precautions like a fire watch, fire extingusher, smoke ventilation, etc. Notice the underlying theme of fire and smoke? There is something about the sparks, heat, smoke and flame in a dry, old house that just takes some of the fun out of the job, ya know? Most of my welding work is done at the shop and flanged together. I have even thought of trying gruv-lock fittings for steam, but I haven't seen or heard of any use. Don't get me wrong ,in the right setting,( a concrete and metal commercial building) I love the smell of burning welding rod in the morning! Also, the last time I asked for a 4" threaded elbow the supplier said " I can order it, but it may be two to three weeks to get it." Best Regards, RonL.

hr

If it can be done off site

it is certainly a do-able option. Wwelded pipe makes for a very good connection, and nice looking attachment.

Check out www.earthlee.com for some really nice welded headers and custom manifolds.

I had a local shop weld some nipples in a steel tank recently. They used a TIG weld and the joints were picture perfect. Didn't leak either

hot rod

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Mark J Evans

I do not know of any instance where grooved pipe is allowed on steam. Hot water, yes.

Brad White_57

Welded vs. Screwed

We specify welded on anything 2-1/2" and up, allowing screwed fittings or soldered copper with dielectric isolation for 2" and under.

Within that we break the valves into butterfly type 2-1/2" and up, ball valves 2" and under.

Generally, Grooved (Vic) is an option in place of welded for 2-1/2" and up. As Mark said, water only, not for steam.

Just our normal specification practice but we have allowed ball valves up to 4" on occasion.

Bill Jirik,

weld vs screwed

On large steamers 4"pipe and larger with headers we still screw together the headers with swing joints for expansion and contraction after that a lot of it gets welded, have you checked the cost of really large cast iron fittings today, besides never had to put a union in to fix a leaky weld fitting.

Josh_10

I am with Brad. In my opinion threads don't belong on anything over 2 1/2". It's like 4 wheelin in a Geo Metro. It is only going to last so long. I think the real issue here is that it takes years and good training to become a certified pipe welder. I know it wasn't easy for me. I am assuming that not too many hydronic guys can justify the expense or the time...

RonL

Weld vs Screwed

Cannot the appropriate swing joints and drop headers be done up with welded pipes?

Brad White_57

Yes, of course

The thermal stresses imposed by expansion and contraction on piping are within the pipe wall material itself and the joints themselves should not move, ideally. I can imagine though that any screwed joint would have some minor creeping, just within it's seal range.

The total length of involved piping in the offset or expansion loop would be the same, screwed or not.

I would submit that welding is the best method for joining piping, but is more costly, requires trained and certified welders and imposes occasional fire hazards. That said, if I could have all welded joints, I would. Just not realistic.