Search the internet for the Valmet Flow Control Manual. Pg 70 explains Xt. You can download for free. Also download the control valve sizing coefficients book from Valmet. There are pages of various valve types and the Xt values are in the tables for each valve type.
I am very familiar with the codes you listed, plus some others for valve testing, including fire and fugitive emission testing.
They do not require 3rd party witness for the tests. The customer decides if they are willing to find and pay someone to witness the test, and the manufacturer...
There is no "common practice" Some chose to take the valves apart to avoid melting the seals, and others chose to weld with the valve fully assembled. There are pros and cons for each.
One place I worked initially demanded all socket weld valves be disassembled before welding. A high...
API 609 refers to APi 598 for pressure testing butterfly valves. Per API 598, all resilient seated butterfly valves are "no seat leakage" during the closure test. API 598 also states that triple-offset butterfly valves with laminate seats are to be considered resilient seated. So triple...
Most common standards for cold temperature testing are MSS SP-134 and ISO 28921-1.
MSS SP-134 is referenced by ASME B16.34 and some API standards, including API 609 which is butterfly valves for the oil & gas industry.
ISO 28921-1 was developed to replace BS 6364 as the BS standard is...
I looked at the 2020 edition. Paragraph 6.5.2 states tabulated stud bolt lengths, dimension "L" in Tables 31 through 41, are based on using 2 heavy hex nuts on two welding neck flanges. Other types of flanges including blind flanges may require different bolt lengths. Refer to nonmandatory...
The definition of double block and bleed varies by standard.
API 6D has pressure coming from both ends of the valve simultaneously and there is a vent in the center body cavity to verify both seats are sealing.
API 608 definition has the pressure direction from only one port, and both seats...
I think the item to focus on is the pressure in the line upstream and downstream from the valve. When you crack it open, you essentially have a fixed orifice size. If the flow rate is changing during this time, then the pressure upstream and downstream of the valve must be changing. This is...
Please read the standard again. Paragraph 6.1 says to use Table 3A, 3B OR Mandatory Appendix VI to determine minimum wall thickness.
Appendix B is Nonmandatory and is for information only.
I don't know what you mean by "design calculation". Wall thickness is simply looked up in Table 3A or...
ASME B16.34 does not provide information on how to calculate the thickness of the bonnet flange. It only provides instructions regarding the required area of the bonnet bolting.
The valve designer must choose the method to determine the bonnet flange thickness. It could be any of the...
You have the right paragraph for flanged valves. It is 6.2.2. It says, "Flanged ends shall be prepared with flange facing, nut-bearing surfaces, outside diameter, thickness, and drilling in accordance with ASME B16.5..."
Flange facing is applicable
nut-bearing surface is not applicable...
