Dear all

Problem is about design of a flange for pressure plus external loadings (Force and Bending Moment). The equipment is ASME SEC VIII DIV.1

We found the following in PV Elite output.

H = (3.14/4) *G^2 * Pequivalent---------(1)

But
Hp = 2b*3.14 G m P --------(2)and
Hydrostatic end force Hd= (3.14/4) B^2 P ------(3)

The query is why equivalent pressure is not used in equationw (2) and (3).

I understand that it is logical because the additional pressure due to F and M do not act on inside but only at gasket location. but I want to know the reference for the same from where PV Elite has taken this approach.

I will be thankfull if any user or PVElite reply for the same

You may see the statement in this post:
http://65.57.255.42/ubbthreads/ubbthreads.php?ubb=showflat&Number=11452

I will self-quote my opinion from another post:
"I would add that for me it makes sense to follow NC-3658.1(b) "the Design Pressure used for the calculation of H […] shall be replaced by a flange design pressure =P+Peq", rather than consider P+Peq as design pressure.

The reason of my opinion is based on Kellogg book that mention “[…] analysis and experience which indicates that, with a properly preightened flange, the bolt load changes very little when a moment is applied, whereas the gasket loading changes appreciably.”
That means Kellogg team expectations were to have external loads transmitted to gasket loads rather than to affect W preightening load, and their Peq concept is a measure of this effect.

Indeed, including Peq only in H (or better said only in HD and consequently in H) means indirectly to consider
HG=W-H= W-PI/4*G^2*(P+ 16*M/PI/G^3+4*F/Pi/G^2)=W-PI/4*G^2*P-F-4*M/G
which is in line with Kellogg approach/ theory of plates. "

Best regards.