Weld-O-Lets for Schedule 10 steel tube

By jon20013 (*****)

Date 05-15-2008 21:21

I wouldn't touch that one but not so much for the schedule 10 vs schedule 40, more because weld-o-lets usually require one helluva lot of weld due to their design and I just don't think it would be a great application on the schedule 10.

By Kix

Date 05-16-2008 13:16

Do you really need to weld the o-let all the way out when welding to a sched 10 piece of pipe?

By jon20013 (*****)

Date 05-16-2008 13:29

From a practical standpoint I would say no, you don't but if you don't and for some unknown reason there's a failure at that joint location the burden is on you to prove why. I recently had a similar question and posed it to those who are MUCH smarter than myself, the answer was only the manufacturer (of the -o-let) can say what amount of weld is actually required for an -o-let product as they are all design around proof testing. Do you want to assume such responsibility without calculations to back you?

By mooseye (**)

Date 05-15-2008 22:35 Edited 05-15-2008 22:38

>Schedule-10/Schedule-40 pipe are in

compliance with the following:
ASTM A-135, and NFPA 13. Both pipe
products have a working pressure rating
of 300 psi maximum and also meet the
stringent requirement for the following
tests:
* Welded Outlets
* Hydrostatic Pressure
* Side Wall Rupture
* Vibration Test.<
Allied Tube & Conduit 16100 S. Lathrop Avenue Harvey, IL

By swsweld (****)

Date 05-16-2008 01:43 Edited 05-18-2008 18:27

I have never installed sprinkler pipe but the jobsites that I work on usually use schedule 10 pipe with shop welded thread o lets not weld o lets. They are always shop welded. I have never read the specs on sprinkler pipe but the specifications in mechanical pipe state that you can install a fitting (weld o let, thread o let, etc) on a pipe that is two sizes larger than the branch diameter. That means that you can put a 2" TOL in a 4" and larger pipe but you cannot put a 2" TOL on a 2 1/2" pipe. When that is encountered you would use a tee. Most companies around here use victaulic fittings.

On a sprinkler system that is designed for safety there should be contract specifications to dictate what can and cannot be used. If still unsure you can send an RFI to the engineer to clarify any confusion on the matter.

By mechan

Date 05-16-2008 02:25

Any time working I worked permit for the sprinkler fitters it was always schd 40 carbon and some schd 80, but very little. Most of the connections we had were like 9/10 threaded, pretty much 0 welding, on the mains there were a couple welds but most were victaulic fittings with threaded on the headers and drops.

By js55

Date 05-16-2008 14:03

jon is right, to really know what amount of filler is required you have to get the info from the manufacturer. But the thing is your talking 1" to 2" O-lets there is going to be so little difference in production between reducing filler and filling them up it isn't even worth concerning yourself with.
The only time I would consider this an issue is with stainless steel or larger O-lets.

By jon20013 (*****)

Date 05-16-2008 15:07

Yeah, the case I was talking about (in my question) was an NPS 18" Sch 20 CuNi and some "idiot" designer had called out a 6" reducing weld-o-let.... HEAPS too much weld, a sweep-o-let would have been a much better choice in that case and, in that case I DID do the calculations and reduced sizing, considerably... still looked awfully odd after welding but good to go!

By js55

Date 05-16-2008 15:22

I've done those calcs too and had inspectors reject them because they didn't look right, and they didnt' think there was enough filler on them. After presenting the data to engineering and getting official approval the problem went away, with a little pouting by QC.

By jon20013 (*****)

Date 05-16-2008 15:44

I really hate to say this, given that many of us are inspectors in this Forum but I really love it when I can make QC pout, lol!!!

By jrw159

Date 05-16-2008 17:55

Jon,
I love it as well. But the reason I love it is because 95% of the times I have seen it, it has been a direct result of an inspector caught with his pants down and/or trying to play "QC God". And in situations like this I say "Let em pout!" :-)

John

By hogan

Date 05-16-2008 18:03

it builds character

By jrw159

Date 05-16-2008 18:08

This is true.

By welderdude (**)

Date 05-16-2008 20:43

i think what you mean is thread o let, right? and the thread o lets i've seen on sprinkler pipe (which was sch 10) didn't look like a 300 lb thread o let like you see in most welding shops. in fact, it looks a lot like a regular coupling. therefore, it will only require one pass with a MIG welder.

as for the sch 40 1" and 2" pipe to be threaded into these thread o lets, it needs to be thicker because of how much clamp down pressure the pipe wrenches will be putting on the pipe. 1" and 2" sch 10 is about the same thickness as the same size copper pipe. if you try cranking down on that with a pipe wrench you're just gonna flatten it.

the contractor who bid the job with sch 10 mains is just trying to cut the cost of the job by using thinner pipe, which is perfectly fine. the reason they want to use thread o lets instead of a victaulic fitting is because of the extravagant cost of victaulic fittings. a thread o let, including the labor to install it would cost at least 5 times less than a similar victaulic fitting. they'll use victaulic for the mains, just because that's about the only efficient way to join 2 pieces of sch 10 together.

the other reason for using sch 10 is because it's lightweight. a crew can throw up a few hundred feet of it in a day using victaulic fittings for the main joints.

the other thing to look at is your application. i don't know what the specific codes say, but i'm sure they differ between residential, commercial, and industrial.

By mechan

Date 05-17-2008 13:59

Uh, since when are vic'd fittings used for the drops to the headers or the actual heads ... oh oh wait their not, nor did the original post give you that information. You see alot of sprinkler lines installed by mechanical means for the mere fact that sprinkler fitters != welders and it is not fesible to be burning rod in alot of those situations. If you can't throw up a few hundered feet of schd 40 a day I think you ought to look for a new job or stop dragging ass, mains don't typically have HUGE amounts of offsets you are throwing up 21'+ foot sticks.

By welderdude (**)

Date 05-17-2008 20:45

from the main line to a branch you can use a vic fitting that has U bolts on one side that go around the pipe and the other side is a cast steel plate with a flat O ring glued to it...that way you can drill a hole in the main and put the vic fitting on and tighten it down. those fittings are very expensive, so that's probably why you've never seen them. i never said anything about using vic fittings on the whole thing all the way down to the sprinkler head. i said threaded.

as for throwing a few hundred feet up in a day, what i mean by crew size is a 3 man crew. what i mean by a few hundred feet of main line sch 10 is 500 ft, including layout of pipe in an area, drilling holes for hangers into concrete, transporting pipe, greasing the ends and the gaskets, tightening the bolts, etc. you also need to look at the environment. if it's a commercial building where all the other trades are working right beside you, then i guess you're just gonna have to work around them. if you're 27 stories up in a tower i don't think you're gonna have access to a forklift...maybe a duct jack. and if it's an occupied building, then it'll take even more time and you probably CAN'T get a duct jack into the area. in that case you might wanna look at sch 10 pipe in 10' sections.

so, the process goes like this:

1. hang main lines
2. drill holes in main lines OR the main lines already have THREAD-O-LETS welded onto them IN THE SHOP
3. fit up vic fittings over holes OR thread pipes into thread-o-lets
4. if using vic branch fittings, use a vic coupling to attach the branch line
5. if using vic branch fittings, the other side of the branch line will have threads on it so you can THREAD more fittings onto it or more pipe to go where you want.

my company has already priced out this whole process for a chilled water system using sch 40 pipe. i've seen the plethora of vic fittings you can get. i've also seen the prices. and that's why you see most branches off of a main as a welded thread-o-let about the thickness of a coupling instead of a vic branch fitting.

i don't have all the answers because i don't know the situation or the codes for his particular area. i'm laying out the possible options, which is NOT what you think i did. i think you need to read my post again, not just skim over it.

By ssbn727 (*****)

Date 05-18-2008 00:07

"We don't need no stinkin Weld-o-lets for that size diameter, schedule 10 pipe... Or is it really tubing??? ahh!!! Now that may raise an eyebrow or two!" ;)
Overkill if you ask me but, what do I know???

Btw, I love being able to make anyone "pout" Yes of course, We need to pay attention in our calcs for the correct fillet weld size as Jeff & Jon mentinoed. ;)

Respectfully,
Henry

By MBSims

Date 05-19-2008 03:37

I just don't see why an "o-let" reinforced branch fitting is needed for this. Why not a threaded half-coupling?

By js55

Date 05-19-2008 13:16

Marty hit the nail on the head. O-lets on sched 10?

By welderdude (**)

Date 05-19-2008 20:27

exactly. the thread o lets they use look EXACTLY like couplings. it's straight, no bevel, is about 3/16" thick, and has threads inside it. these guys all think the first post is talking about a full size 300 lb weld o let. wrong! and all it takes is a standard 3/16"-1/4" FILLET weld to seal it up. no high pressure involved. no UT. no X-ray. in fact, no QC for that matter. all they do is hydro test. fill it up with water and pressurize it to 100 psi and look for leaks. and for all you doubters out there, the victaulic fittings are what usually leak, not the welds on the thread o lets.

By swsweld (****)

Date 05-20-2008 01:52

Looked at some sprinkler pipe on a job Friday and it looks like thread protectors used instead of thread o lets. Shop welded w/GMAW. Thread protectors being the same thing as couplings. What welderdude describes is what I see on the commercial jobs I often work on.