As you know instead of having one long stud bolt, since valve is threaded, two shorter machine bolts are installed which meet each other at the mid point of the valve, how do we differentiate the flange analysis for lug type valves from from the conventional valves-bolts?
Thanks

Don't try at home.

Jozm
Did you mean flange leakage analysis?
If so, I am not sure it's the applicable case...

Are you saying that you have a lug-type valve with a full penetration for bolt holes, that are each threaded from either side to permit a bolt to be clockwise tightened?

I'd double check to verify whether or not the bolts are actually supposed to meet in the center - they shouldn't - and I'd not even have a full penetration were I the manufacturer so as to prevent accidental reverse-threading if someone accidentally put in a longer bolt than intended.

Otherwise, flange leakage analysis should be the same as normal.

Mr. Fletcher,

Can the Lug type butterfly valve's connection to pipe be treated as a flange? Would you explain more?

I thought only flange type butterfly valve is applicable to flange leakage analysis.

MK,

It's worth noting that lug type butterfly valves often are designed not to be used with a gasket, but in of itself serves the role of gasket between two flanges. You'll want to validate with the manufacturer to get the values you need to perform your leak analysis if this is the case. If it is not, then treat it as any other valve.

To that end, the manufacturer is providing an element that mates with an ASME flange, and it is their responsibility to meet the flange's capabilities or emphatically announce what the limitations of their product is if it does not.

Thank you for the detailed explanation.

Thanks Michael, I expressed it badly, of course there should be some gaps b/w bolts...
good to know that they shall meet ANSI flange criteria.