What code says about branch connections?

[ukmet]

Dear All,
I am here once again to learn from your precious experience. Please guide me on following points:

1. What are the requirements of code for branch reduced connection. We have 3" line from which 1/2" branch connection is to be made.Why we cannot direct weld it with pipe ? Why reducing tee or weldolet is required?

2. Is there any limitations where to use a reducing tee and where to use a weldolet?

Please quote me code references if possible.

 

[BigInch]

Weld metal must be replaced and sufficient reinforcement must be provided to compensate for the metal not present due to the outlet hole through the wall thickness. A weld-o-let will provide that for you. The easy rule is, if you see a commercial reducing tee in the catelog in the size you need, use the commercial size tee. If there is not a reducing tee in the catelog for the sizes you think you need, then use the weld-o-let. The code references are easy to find. Look for the big pictures right after the sections on wall thickness sizing. B31.1, 3, 4 and 8 all have them.

"People will work for you with blood and sweat and tears if they work for what they believe in......" - Simon Sinek

 

[StevenHPerry]

1) Lots of code requirements per code and lots of codes to choose from. ASME B31.x will probably allow you to use a stub-on for 3"x0.5" connection, but a calculation or two will be required.

2) Your code probably does not limit the selection of tees, weldolets, stub-on's etc, but economics probably does. There are standard tees (ASME B16.9 for instance) and standard weldolets (see Bonney Forge's catalog). The advantage of weldolets is that there are two weld on a continuous pipe. Tees require cut and prep on the header pipe and three welds. However, at some sizes and pressures, the weld from the weldolet to the header pipe can require more weld than making the "extra" weld on a tee. Weldolets can also require weld thicknesses large enough to enter the heat-treat-required size ranges.

But that's mostly academic if your test case is a 3x0.5. Use a sockolet and move on.

- Steve Perry
This post is designed to provide accurate and authoritative information in regard to the subject matter covered. It is offered with the understanding that the author is not engaged in rendering engineering or other professional service. If you need help, get help, and PAY FOR IT.

 

[BigInch]

Besides, you will appreciate the added reinforcement at the connection when the small line vibrates all the time, or some heavy guy steps on it.

"People will work for you with blood and sweat and tears if they work for what they believe in......" - Simon Sinek

 

[ukmet]

thankyou very much to you all