Use a weldolet or a split tee ?

[eml]

When making a branch connection for a hot tap, we always use a split tee for a size-on-size connection. When we have a branch connection size smaller than the header, our piping designers always want to use weldolets. What is anyone's experience regarding the use of weldolets when you are close to size on size, i.e. 4" sch. 40 on a 6" sch 40 ?

 

[11echo]

In my experience you only start to think about using weld-o-lets when your at half the main header size ...so if you were talking about a 6" main header you would start to think about a weld-o-let at below 3". I say "think" because the contractors I've work with don't like weld-o-lets! ...except in the the real small sizes (1 1/2" and below). The reason is that weld-o-lets take a lot more work to install them ...more welding & installation time. That plus they can get the main header glowing red by the time you get all the welding done on a weld-o-let installation of any size. I use a lot of slit tees, Red. tees, and half couplings myself, but I ran across something called "Tee-Let" (check out this link)

http://www.meritmfg.com/

It explains the differences with a "tee-Let" & Weld-o-let installation. Hope this helps, Good Luck! ...Mark

 

[MJCronin]

11echo,

You cannot substitute any kind of piping "tee" or weldolet fitting for any other type of split/slit or weld-on fitting and be in conformance with the rules of the ASME B31.1/B31.3 piping codes.

If the piping system is installed to these codes, the tee(or intersection) must either meet the dimensional requirements of ASME/ANSI B16.9 or be certified by the manufacturer to specific pressures and temperatures.

Both codes also allow for calculation of "areas of reinforcement" for the unique field fabricated cases. These calculations are supposed to be performed by an Engineer....

For many years the folks at Bonney Forge (weldolets)and WFI have been warning against non-certifed, field designed, and "shade tree" engineered piping fittings. You simply cannot design, fabricate, slit and reweld-up anything that you want in a B31.1/B31.3 piping system......

I would like to see a Mr. John Breen weigh in on this issue

My thoughts only..................


MJC

 

[11echo]

MJC ...I agree with you TOTALLY, but you see the connecting fittings I indicated all comply to B31.3 & B31.8. These are all indicated in the piping spec.s of our client. However there are code compliant alternatives. I've seen a number of contractor made "field decisions" as to what they'll use (this is in the oil field area - a little more relaxed then say a refinery). All I'm suggesting is to talk with the contractor, get their ideas. Then walk it thru with the client or engineering dept. I find the being in the middle (design) you need to get both ends talking together BEFORE things are done out in the field, it'll save you big time in the long run!!! ...AGAIN, my 2 cents. ...Mark