Forged Branch Outlet Fitting vs. Standard Weldolet

My understanding is that a Pipet is the same thing as a Weldolet/Thredolet etc. but the former is manufactured by WFI ad the latter is manufactured by Bonney Forge. Bonney Forge O'lets are commonly used in process piping. Whether to use a O'let versus a tee is based on size and economics/ease of welding. Piping spcifications will provide tables of size ranges where tees versus O'lets are to be used. Usually tees are used in full size branches or slight reductions in branch sizes and weldolets are used when branches are a lot smaller than runs.

Thank you Snickster. So I am assuming if specifications for a tee vs. an O'let allow for an O'let to be used, use of a three weld option or one weld option would really depend on if it costs more to buy a one weld outlet like the Pipet, than it would be to pay a welder to do 2 extra welds for a more standard O'let. Do you think this might be the reason more people are not using a one-weld option? Or do people not know something like that exists?

It appears you are conflating some things. A tee connection has 3 welds required and an O'let requires two welds (including branch weld) so extra welds (x1) would be required for a tee not an O'let. Everyone in piping knows an o'let exists and a pipet is just another name for an o'let by another manufacturer. So you use a tee or an o'let. O'lets have to be used in smaller diameter because tees only come in a few reduced sizes. For instance I think a 10" tee can only be found down to 4" branch sizes so there is no other choice when you get below 4" for a 10" run size.

However O'lets are usually not used for larger size branches versus run even though they may be cheaper or use less welds. I am not sure exactly why but it may be due to that they have a higher stress intensification factor (SIF) or other reasons.

Attched is a typical PIP piping spec which has the branch connection table that shows what branch connections are to be used for what size. Also the following link gives some information on O'lets and advantages. Also if you search "Olet versus tee" you will get more information on why one is used over other.

Note that in the branch connection tables of the PIP they list B-Branch Weld and P-Branch weld with reinforcement. However most clients do not use these connections but just use E-Reducing tee all the way down to the sizes where the W-weldolet and S-socolets are used.

Here is typical client 150# piping spec with branch table that shows what clients typically use for branch connections.

Steph07 said:

Pipet vs. a standard three-weld option like the Weldolet

Click to expand...

Are we all talking about the same terms or am I misunderstanding?

This image shows a flanged 'pipet' that does save some welding:



See

Pipet[sup]®[/sup] is WFI's brand name, used to avoid encroaching on Bonney Forge's trademarked terms Weldolet[sup]®[/sup], Thredolet[sup]®[/sup], etc.

A 'nipple olet' i.e. BF Nipolet[sup]®[/sup] or WFI Nipple Pipet[sup]®[/sup], is sometimes proposed instead of a SOL + TOE nipple to save a weld but the cost to do a small socket weld at least in a non-union shop environment is probably at best a wash vs the extra cost of the fitting. You also lose flexibility in nipple length.

Depending on the size and unit cost of the two butt welds eliminated you could maybe eke out a small savings with a 2" flanged olet vs WOL + pup + WNRF as shown in Gator's post above.

I'm pretty sure the OP and Gator is talking about what are sometimes called "weldoflanges"

I came across them about 30 years ago made by this lot - Promat -
Think the best use is the more exotic materials which can be a bitch to weld and tale time and money. Your standard weldolet and flange in A105, probably not much in it.

The Pipet name and a number of other seem to be mainly Indian based.

The world of piping design is very conservative and I guess the supposed advantages are not enough for the weldoflange to become dominant over the weldolet and separate flange combination.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

Thank you everyone for your comments. Very helpful. I think my original question was confusing and should have specified a flanged outlet. LittleInch made a good point, I think the advantages of the weldoflange are not enough. The advantages of a weldoflange would have to be greater than the time and cost it takes a welder to do one extra weld. THanks!

Haha, we call these weldoflanges a 'flangolet'.
In my experience (but we're EU based, so have less than perfect access to stocks from BF or WFI), is that anything other than a regular olet will cost you a fortune, and is likely never interesting from a commercial POV. Perhaps only in some circumstances under a mechanical point of view.

Huub
- You never get what you expect, you only get what you inspect.

O-lets that operate in the crrep regime have a weak point at 45 degrees from the intersection of the 2 pipe axes- for some high temp materials ( P91) one should incorporoate the weld
creep strength reduction factor in defining the required wall thickness at the weak point or bettter yet ,use a forged tee.

"...when logic, and proportion, have fallen, sloppy dead..." Grace Slick

I'm interested in using Nipolet/Pipet & Flanged Pipet/Flangeot in sizes <2" where buttwelds are more difficult in a field environment. Would come in handy in many situations, depending on service. I work in refining in a fairly remote region, without great access to welders, and union rates.