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Threadolet branches
- AllanD
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12 years 8 months ago - 12 years 8 months ago #8104 by AllanD
Threadolet branches was created by AllanD
Hi I'm looking for a little help with some branch details.
I have to look after a design of an oil pipeline and the sugested design is to use threadolets for the branch points. the current design has DN20 threadolets on DN 250 & DN300 main pipes, DN25 threadolets on DN250 & DN400 main pipes and DN40 threadolets on DN250 main pipes. Due to other design issues I don't have a lot of confidence in the designer.
I have been more used to working on older systems where stub in / out was the standard practise.
So I am not really sure as to the point in using threadolets, especially as the design requires a threaded pipe to fit the threadolet, and a flange on the pipe. That seems to be 3 connections where failure is a posibility as opposed to stub in / out which would only have 2 connections where failure is a posibility.
Any comments would be greatfully received.
Thanks
I have to look after a design of an oil pipeline and the sugested design is to use threadolets for the branch points. the current design has DN20 threadolets on DN 250 & DN300 main pipes, DN25 threadolets on DN250 & DN400 main pipes and DN40 threadolets on DN250 main pipes. Due to other design issues I don't have a lot of confidence in the designer.
I have been more used to working on older systems where stub in / out was the standard practise.
So I am not really sure as to the point in using threadolets, especially as the design requires a threaded pipe to fit the threadolet, and a flange on the pipe. That seems to be 3 connections where failure is a posibility as opposed to stub in / out which would only have 2 connections where failure is a posibility.
Any comments would be greatfully received.
Thanks
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- 11echo
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12 years 8 months ago - 12 years 8 months ago #6351 by 11echo
Replied by 11echo on topic Re: Threadolet branches
Thread-o-let, sock-o-let, and weld-o-let are far superior connections then a stub-in! The only issue with the O-let connections is they require more welding then a stub-in, and in larger sizes can have the main header at the branch connection glowing cherry red! Rule of thumb in my part of the world, you use red tees (or split tees) for branch connections down to about half the size of the main header, below that we call out O-lets. Stub-ins are only used on very low pressure systems …i.e. gravity drains & some vent lines. Good Luck!
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- hc
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12 years 7 months ago - 12 years 7 months ago #6168 by hc
Replied by hc on topic Re: Threadolet branches
Are you positive they are referencing threadolets as your branch connection? On an oil pipeline my experience says that your connection would be a sockolet if your branch is small bore and a weldolet or reducing tee if its large bore (depending on sizing). Question: Shouldn't you be welding until after your first valve? KEEP IN MIND I don't have a ton of experience with stub-ins but in my limited experience stub-ins have been quick and dirty old skool type connections....I only see them in very tight conditions or special conditions when an olet/red tee won't fit. There ends up being less welding with a stub-in but, correct me if I'm wrong.....a stub-in needs to be engineered where a olet doesn't.
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- AllanD
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12 years 7 months ago - 12 years 7 months ago #6172 by AllanD
Replied by AllanD on topic Re: Threadolet branches
Hi hc, yes the drawings clearly states threadolets. They have now changed 2 to weldolets becuase it wasn't pissible to screw the pipe into the threadolet.
And they are also welding the branch pipes to the threadolets after they have been threaded in. I am tearing my hair out with a bunch of clowns who have no idea what they are doing.
My expereince is mainly from the shipping industry where cost is what matters, and thats why I am more used to seeing stub ins.
And they are also welding the branch pipes to the threadolets after they have been threaded in. I am tearing my hair out with a bunch of clowns who have no idea what they are doing.
My expereince is mainly from the shipping industry where cost is what matters, and thats why I am more used to seeing stub ins.
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- hc
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12 years 7 months ago - 12 years 7 months ago #6374 by hc
Replied by hc on topic Re: Threadolet branches
So they are putting in a threadolet and then backwelding it. Is this new construction or an existing tie-in? Will there be a valve installed at the branch.....does it need to be back welded?
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- Jop
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12 years 7 months ago - 12 years 7 months ago #6420 by Jop
Do it once and Do it Right
Replied by Jop on topic Re: Threadolet branches
Allan, D
There seems to be a contradiction in your information.
You posted your “Years of Experienceâ€: as “1†year. This would suggest that you are a novice.
Then you went on to make the following statements:
1. I have to look after a design of an oil pipeline – This implies that you are “Supervising†others as well as the work. What is your Title, Role and responsibility on this project?
2. I don't have a lot of confidence in the designer. – This implies that you are not a “Piping Designer†What are you?
3. I have been more used to working on older systems – This implies a history and or experience with some kind of piping. How long was this?
4. I am tearing my hair out with a bunch of clowns who have no idea what they are doing. – This implies that you are calling the piping Designers “Clownsâ€. Is that really what you are thinking and saying?
5. My experience is mainly from the shipping industry where cost is what matters. - This again implies some undetermined amount of prior experience. What kind of experience was this and how long were you in this particular job? You may also want to consider that whether it is Drilling, Pipelining, Refining or Shipping the first and most important issue is "Safety", cost is not first in any of these.
These all suggest that you might have much more experience than one year. So, what is it “one†year or something else?
If you in fact have more than one years experience then you should know who is in charge of the Piping Material Line Class Specifications. You would also know what this document includes and the proper route to questioning both the method of construction (Butt-welded, Screwed, or Socket-welded) and the Branch Table which every Line Class is to use.
There seems to be a contradiction in your information.
You posted your “Years of Experienceâ€: as “1†year. This would suggest that you are a novice.
Then you went on to make the following statements:
1. I have to look after a design of an oil pipeline – This implies that you are “Supervising†others as well as the work. What is your Title, Role and responsibility on this project?
2. I don't have a lot of confidence in the designer. – This implies that you are not a “Piping Designer†What are you?
3. I have been more used to working on older systems – This implies a history and or experience with some kind of piping. How long was this?
4. I am tearing my hair out with a bunch of clowns who have no idea what they are doing. – This implies that you are calling the piping Designers “Clownsâ€. Is that really what you are thinking and saying?
5. My experience is mainly from the shipping industry where cost is what matters. - This again implies some undetermined amount of prior experience. What kind of experience was this and how long were you in this particular job? You may also want to consider that whether it is Drilling, Pipelining, Refining or Shipping the first and most important issue is "Safety", cost is not first in any of these.
These all suggest that you might have much more experience than one year. So, what is it “one†year or something else?
If you in fact have more than one years experience then you should know who is in charge of the Piping Material Line Class Specifications. You would also know what this document includes and the proper route to questioning both the method of construction (Butt-welded, Screwed, or Socket-welded) and the Branch Table which every Line Class is to use.
Do it once and Do it Right
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