Welding Problem 1500# Sch 160 to 1500# Sch 129

[RussKunzman]

I need to size a probe to be installed in a power plant steam line. The main line is 16 inch 1500# Schedule 120. The port to be welded on this line for the probe is 4 inch 1500# Schedule 160 and will terminate with a 4 inch 1500# flange to attach the probe to. My question is this, What options are there for this and what minimum length can be achieved for the distance from the outside face of the 4 inch flange and the outside wall of the 16 inch line.

I am a chemist and not an engineer so I am not familiar with the code requirements.

I have been told that the weld-o-let necessary to do this has a hub lenght of 10 inches and this sounds crazy fo a 4 inch port.

Thanks for any help you can give me.

 

[pablo02]

I'd suggest reviewing your requirements with someone (qualified) in your company or a hired welding engineer to assist you... you'll need to know the material of the pipe, the appropriate welding materials, any stress relief requirements, as well as any reinforcement of the joint needed, any NDT required, as well as what it will take to appease the AI (authorized inspector) for your facility. Many of us can tell you what we would do, but....

you're right, a "weld-o-let" sounds crazy... check with the crew or contractors who perform your boiler repairs, they should be able to assist you or provide a contact

 

[unclesyd]

I heartily agree with Pablo02 in that you should get some engineering assistance from someone well versed in ASME B-31.1 or the codes for power piping in your jurisdiction. A weldolet or long weld neck flange are often used in power piping to minimize stresses. Your company should have some type of piping code to cover the power piping on your site. Usually long nozzles are used for clearance, insulation, bolt removal, etc.

Your nozzle addition to the steam line needs to be engineered.

 

[bvi]

The minimum distance between the flange and the run pipe will be governed by consideration of bolt removal. The opening cut into the run pipe may require additional metal for reinforcement, which can be provided by a branch connection fitting such as a weldolet. Alternatively, there may be sufficient metal already available in the pipe wall, such that the branch can be welded directly to the run pipe without additional reinforcement, another alternative is the use of pad reinforcement if additional reinforcement is needed. To determine this requires Code calculations to be performed. Use of a standard fitting for the application, such as a weldolet, does not require such calculations.

 

[GenB]

Depending of what part of the Country (US) or the world are you. in the US and Canada you will need a certified ASME Stamp holder of S or pp to perform the engineering/responsibility of the job,
you should consult the jurisdiction boiler Inspector for advise.
ER