how to do hot tap on 30" existing line. branch=20"

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17 years 7 months ago - 17 years 7 months ago #8678 by zahra
Dear all
hi

I was wondering if it is possible to weld a 20" branch (stub on) on an 30" in line header?
30" line is pressurized with gas.

I appreciate your reply
Best Regards

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17 years 7 months ago - 17 years 7 months ago #3778 by Jop
Replied by Jop on topic Yes it is. Check around
Yes it is. Check around on this website for more information.

www.tdwilliamson.com

The address below has more specific date about possible line conditions

www.tdwilliamson.com/hottaptdw/tapping/860tm.htm

Do it once and Do it Right

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17 years 7 months ago - 17 years 7 months ago #3779 by Ollie
Replied by Ollie on topic Try this
• Attach a split 30 x20 tee
• Weld on a FB flanged by weld ball valve ( this would be a specialty item ie a modified Flg. BV )
• Attach hot tap drill to Flange face of BV
• Open BV
• Drill hot tape
• Withdraw drill
• Close BV
• Continue branch connection from Flange face of BV

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17 years 7 months ago - 17 years 7 months ago #3780 by zahra
Replied by zahra on topic Hi could you please tell me
Hi
could you please tell me that wheather the split tee is a pressure retaining part or it is just as a reinforcment ??

I had pland to weld a piece of 20" pipe on 30" header and then as a reinforcment fabricate a full or half saddel around header.
in this way the saddle is not a pressure retaining part and there is no need to have a circomfrencial weld.
two part of full saddel will be join together with two joining bar.
then weld a flange to 20" pipe and and then 20" full bore ball valve.
could anybody tell me if this is a practical design or not.

highly appreciated your reply

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17 years 7 months ago - 17 years 7 months ago #3781 by Jop
Replied by Jop on topic Zahra, Your plan as described, does
Zahra,

Your plan as described, does not sound like a good idea to me.

I do not recommend that you try to jury-rig some cheap, quick fix method to do this tie-in.

The people (T. D. Williamson and others) who do this for a living have made or assist others to make tie-ins and they know what works and what does not. I have never seen your suggested method offered by any of them. I also do not think your method will meet the B31.3 Code requirements for a reinforced branch.

Again, I strongly urge you to get a representative from T. D. Willianson or other Tie-in company to give you some proper and sound advice on your specific case.

Regards, Jop

Do it once and Do it Right

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17 years 7 months ago - 17 years 7 months ago #3782 by zahra
Replied by zahra on topic Hi I have studied the TDW
Hi
I have studied the TDW method as much as they described it in their web site .
also there will be a committe of profesional engineer which will consider my procedure before execution.
meanwhile I want to find my flaws.
what is the diffrence between my idea and what TDW will or other qualified companies do???
please correct my about weakpoints of my desing.

PS: In iran all the hot tap operation will be done by national iranian oil company and no forign company can be involved.
and they have highly qualified team.
but i am not sure about their method.


highly appreciated your reply

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