Flanges for Heat Exchanger
Flanges for Heat Exchanger
(OP)
I have a problem to specify the appropiate material of flanges of a heat exchanger, this is a old equipment and only a section required replace, this section will be formed by a rolled plate (ASTM A-516 Gr 70) with a flange in each end. The original drawings of equipment are not available, only a detail drawing of flanged joints is available. First, we think use flanges according to ASTM A105 (26 in. diameter) but the dimensions on detail drawing are not similar to flange standard (dimension ANSI B16.47)
One supplier propose us fabricate flanges for steel casting with similar composition to ASTM A105.
Other supplier propose us fabricate flanges upon ASTM A216 WCB steel casting and then to forge according to ASTM A105.
I think that fabrication is the correct choice, because the dimensions required are not standard, but... How do I request these flanges?.
One supplier propose us fabricate flanges for steel casting with similar composition to ASTM A105.
Other supplier propose us fabricate flanges upon ASTM A216 WCB steel casting and then to forge according to ASTM A105.
I think that fabrication is the correct choice, because the dimensions required are not standard, but... How do I request these flanges?.





RE: Flanges for Heat Exchanger
I should supply us more information about your heat exchanger in order to clearly defined the situation.
Your flanges caould be made by ASTM A105 or ASTM A-350 LF2 thinking that the rolled material was made by ASTM A-516 Gr.70. You should take into account design data and fluid composition.
Anyway if the mating flanges are not standard you will purchase a custon flanges, which might be coupled with the existing one, specifying all necessary technical data to the selected mill supplier.
SD
RE: Flanges for Heat Exchanger
I would expect that you would need to have the final flange design verified and that you might need a code stamp on the replacement part(s). This is something you might want to investigate.
Regarding the flange materials, I have only ever seen either ASME SA105, SA105N, or SA350 LF2 (Class 1 or Class 2) forged flange materials used with 516-70 shells. The choice would be dependent on service conditions (e.g., H2S, temperature, pressure rating).
RE: Flanges for Heat Exchanger
Are you an experienced pressure vessel design engineer to tackle this sensitive job? As you can see from replies, you are being reminded of the principles of designing flanges, taking in account many factors for material selection and even the applicable code selection.
If not, you should hire a professional designer to perform the design calculation for the replaced section.
Cheers,
gr2vessels
RE: Flanges for Heat Exchanger
See the section on "Large OD and TEMA Flanges"
Regards,
Mike
RE: Flanges for Heat Exchanger
RE: Flanges for Heat Exchanger
RE: Flanges for Heat Exchanger
I'm not pressure vessel engineer design, I work for a construction company, a client sent us a detail drawing for this job, my problem is... how request bids to flange suppliers?, obviously they need data about material, dimensions and ratings standards.
The reply of SnTMan and their reference to TEMA is new to me.
I think for the required flanges, dimensions should be according TEMA and material according to ASTM A105 forged and rolled steel.
Does it correct?
RE: Flanges for Heat Exchanger
Also, you should investigate the regulatory requirements in your location. In many locations, you would only be permitted to fabricate pressure vessel parts if you held a Certificate of Authorization from ASME and could Code Stamp the vessel and/or parts. In addition, fabrication may need to be inspected by an "Authorized Inspector".
I am aware of one situation where an end user provided drawings for two old heat exchangers and asked a fabricator to build "replacements in kind". The fabricator was not particularly knowledgeable on the ASME Code rules and by the time the vessels were finished, there were serious enough problems that the vessels did not meet the Code requirements and they were not accepted by the regulatory authority. I don't think the fabricator was ever paid for their work since the vessels could not be used.
ASME is the American Society of Mechanical Engineers and they publish a general pressure vessel code called Section VIII Division I which can be used for designing and building any pressure vessel including heat exchangers. Only very recently have they included specific rules for designing and building heat exchangers.
TEMA is the Tubular Exchanger Manufacturers Association and they have published rules relating to the specific design of heat exchangers for many years. Before ASME included specific rules for heat exchangers, the TEMA rules were used. Even now, the TEMA rules are often used instead of the ASME rules.
RE: Flanges for Heat Exchanger
Regards,
Mike