Use of Piping Components in Vessels

[johnnymist2003]

Hi all,

perhaps someone could help clarify the following :

I have an heat exchanger, designed to ASME Section VIII, Div.1 & TEMA. It is a single pass unit, the shell is made from say NPS 6 pipe (or any similar nominal pipe size). Because it is a single pass unit, it has no partition plates.

Am I permitted, in terms of the rules of ASME Section VIII, Div.1 & TEMA, to make use of piping flanges to ASME B16.5 (or for bigger sizes ASME B 16.47), for the girth flanges and flat channel covers (if there are any)?

Please could you also tell me where in ASME Section VIII, Div.1 it prohibits or endorses the use of ASME B 16.5 / B16.47 piping components for girth flanges / flat covers in particular.

Thanks.
John

 

[bmoorthy]

UG 34 for Flat heads (this does not prohibit use of standard flanges)

Appendis 2 for girth flanges. here again use of standard flanges are not prohibited

 

[jte]

Hi Johnnymist-

Take a look at the following sections of Div. 1:

U-3 provides a list of the latest standards referenced, including B16.5 and B16.47.

UG-11(a)(2): "Flanges and flanged fittings may be used at the pressure-temperature ratings specified in the appropriate standard listed in this Division..."

Finally, UG-44: "The following standards covering flanges and pipe fittings are acceptable for use under this Division in accordance with the requirements of UG-11."
UG-44(a) ASME/ANSI B16.5, Pipe Flanges and Flanged Fittings
UG-44(i) ASME/ANSI B16.47, Large Diameter Steeel Flanges, NPS 26 Through NPS 60

Between UG-44 and UG-11, it seems that the use of B16.5 and B16.47 flanges (to include blind flanges) for Div. 1 vessels is explicitly acceptable. Their location is not discussed (for example, they are not limited to use for nozzles only); therefore whether they are nozzle or girth flanges is irrelevant.

I would suggest that for girth flanges which could be handling a large moment (or tensile load) that you calculate an equivalent pressure and account for the moment or load that way. From Section III (though I havent checked a recent edition) the formula is:

Peq = (16*M/pi*G^3) + (4*F/pi*G^2)

Peq is equivalent pressure, M is moment in in*lb, G is diameter of gasket reaction (see VIII-1 Table 2.5.2), F is axial load in pounds.

jt

 

[bmoorthy]

I agree with jte.