Dear All,

The rules of UCS-79 of ASME BPVC SECTION VIII-1 are sourced from WRC-158, does any body have this valuable source in his/her library?
The rules of forming strains due to cold forming are also contained in "Heat Treatment in Pressure Vessel Technology" by C. Bouhelier of France, if anybody ...

Dear All,

I have following questions about the knock out vessel, the fluid is natural gas, the vessel is vertical

1- What is the acceptable range of the vapor velocity exiting the vessel?
2- What is the acceptable range of the liquid velocity exiting the vessel?
3- Why LCV is used at the outlet ...

Correct, it is 0.5 as per B31.3.

All material mentioned by you fall under ferrite category.
The value of Y is a function of material and the design temperature. The use of Y is also contained in ASME Section I and B31.1.
ASME Section VIII-1 and ASME Section IV use the value of Y always 0.4 and is incorporated this value in UG-27 ...

I assume you want to know which is more stringent API 650 or 620?

Overall I would say 620 is more stringent than 650 but you cannot use 650 in place of 620 if your tank falls under 620 scope.
Please read the scope and applicapability of both standards, that is a must.
Can I go to 650? Can I go to ...

Dear Salzx,

I fully agree with you, the case as you noted, seal welding becomes mandatory as per 114.2.3

Octane,
you asked
"Please explain what's the reason code says to cover all the threads with seal welding? "

Please read 2nd paragraph of Foreword of any ASME BPVC Code book. It reads " The Comitte's function is establish the rules of safety............." so covering the threads with seal welding ...

Now please see from VIII-1
UG-43(e) in VIII-1 says that other means of sealing, if provided, then other than standard taper threads may be used in threaded connections. Seal welding is one of the "Other means" as referenced in UG-43(e).
Expanded connections are prohibited for flamable and/or noxious ...

Section I (Rules for the construction of Power Boilers) also permits the seal welding at some places like PG-31, PG-59.1.1.4 etc.
Intersting in Section is that you may use seal welding of threaded fittings after final hydro test if PW-54.3 is satisfied.

Octane,

Let me now quote you from B31.3.
Para. 311.2.6 says seal welding may only be used to prevent the leakage not to contribute towards mechanical strength.
Then para. 328.5.3 says seal welding shall cover all the exposed threads and it shall be done by qualified welders.
Also, keep remember ...