Bolt lengths in ASME B16.47 2

[anders_1]

ASME B16.47's dimension tables list stud bolt lengths for raised face and ring joint flanges but don't specify what combination of WNF or Blind Flanges this applies to. This is unclear, as their thicknesses vary significantly - for example, a #900 NPS 28 flange is 5.62" thick for WNF but 6.75" for Blind. This is based on Nonmandatory Appendix D: Method for Calculating Bolt Lengths.

How should I interpret the bolt lengths values?

 

[LittleInch]

What year is that code?

I'm looking at 2017 and that column has disappeared, perhaps because of that exact issue....

Google seems to say e.g. 19.75 for a 28" class 900.

One source says it is calculated based on one WN flange connected to a blind flange, which sounds good to me

e.g

https://www.federalflange.com/images/standards/B16.47 A&B.pdf

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[bcd]

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 Appendix D for the method to calculate bolt length.

 

[anders_1]

I was looking at the 2020 edition. I missed that sentence in Paragraph 6.5.2, but just took a look and you are correct, thanks @bcd.

(And thanks for the response @LittleInch, I definitely should have included the year of the standard in my question)