[Yaroslav Golovchenko]

is it allowed in engineering practice to weld T-piece with T-piece?
(see the picture below)

In my opinion it can be a problem, because the weld end for T-piece is bigger (wider) compere to pipe or any other fittings,
I mean that the weld between two T-pieces will be wider compared to weld of T-piece and pipe.

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Discussion

[James Pennock]

Yaroslav,
There is absolutely no problem welding two TEE fittings end to end on the run or welding an elbow fitting to the branch of a TEE fitting.
If you are close to a fitting supplier or a pipe fabrication shop it would be worthwhile to take a trip to these places and have them show you real life examples of these.

It would be helpful if you would give us some information about yourself, such as your training in piping and your years and type of experience

[Yaroslav Golovchenko]

Dear Jop, thank you very much for your answer
I our practice direct connection is difficult, but the most important moment in case of alterations, both details (fittings) will be unusable if there no intermediate pipe considered. Isn’t it?
____________________________
About myself, I am piping engineer/designer as already for 7 years, mainly for Gas, Oil, Less for Water projects, (I will update my profile)

[James Pennock]

Yaroslav,
This: “I our practice direct connection is difficult, but the most important moment in case of alterations, both details (fittings) will be unusable if there no intermediate pipe considered. Isn’t it?” type of thinking is wrong.

The way your sketch shows the piping configuration is correct. Do not add extra pipe spools between fittings unless it is required for specific Fitting make-up.

It would be advisable for you to spend some time (before work, during lunch, after work, at home on the week-end) looking through all the posts on this forum. You will find that this type of question has already been asked.

[Mark Layport]

I’d like to add something to this, abit different than JOP’s explanation (although he’s input is not wrong), and that is COST $$$! …Every time you weld pipe it cost money, the bigger the pipe, the higher the cost. SO if you can generate a piping configuration that reduces the number of welds the better the design! …Now having said that their are other aspects of a “good piping design” so don’t think just reducing the number of welds is the only way to a “good design”! …AND, it’s not unheard of cutting out fittings (normally large diameter or special alloy fittings) and re-dressing the ends to be re-welded in some other configuration. But again, this takes time …time is money, so be sure that it is worth the effort to do this, as apposed to just re-ordering another fitting and welding it in.

[Anton Dooley]

Yaroslav,

Take a look at this:http://pipingdesigners.com/contents/blog/146-blog-1p-fitting-to-fitting and all the other articles under the “Content” menu.

There is some really useful information there.

Better still, print them, and make a binder to use as a reference / training / refresher manual.

[SHAY O'CONNOR]

Yaroslav,

Looking at the piping arrangement here there’s absolutely no issue with butt welding fittings together of any sort on typical SS or CS specs and the like.
To reiterate 11echo in other words:
In fact all good piping designers should strive for this type of configuration because of cost as well as design.
You are saving in shop labour here reducing welds on time spent welding and material costs with the extra pipe piece between.
As a designer coming from a piping fabrication and installation company back ground this is how we were always taught to design taking into account the fab shop and associated extra costs. Too many designers are not aware of this and will add in extra fittings and welds when they are not necessary.
I understand there will be cases where there needs to be pipe between fittings in high purity situations to allow the weld head in to produce the weld.
Personally if I took a design with poc pieces of pipe between fittings I would alter and produce the iso’s butted together for reasons giving.
This is what I instruct my team to do also where applicable as good piping practise.

[Clarkson Heaney]

Hi Guys,

Newcomer to the site, I’d just like to add something, drawing from my Pipefitting back ground.

Agreed Shay and 11echo, cost must be at the forefront of all designers work, but i think what Yaroslav means when he said ” weld between two T-pieces will be wider compared to weld of T-piece and pipe” is refering to the asthetics of the finished weld. We all know the the most important factor in butt welds is the matching ID (inside diameter) making it look pretty is then up to the welder. 🙂

[Author]

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