Fabricated Vs Forged Flanges-National Board Report

[vvvipin]

Can someone direct me to material (preferably online) on this topic. I understand that the National Board has an excellent report on this topic, detailing the "Chinese flange incident" of about a decade ago.What exactly is this 'incident' and how does one get to read this report?

As per this report it has been established that forged flanges are superior to fabricated ones.I require to convince my client about this.

Thanks

V.V.Vipin

 

Hello VVVipin,

You can contact the National Board of Boiler and Pressure Vessel Inspectors via e-mail. The article regarding failures of (fabricated) flanges made in China was published in one of the National Board Bulletins at the time of the incident - I don't remember which one. Perhaps you should e-mail Francis Brown, P.E., Staff Engineer, at:

fbrown@nationalboard.org

Mr. Brown will be able to help you to get a copy of the original bulletin with the article at issue. There were several follow-up articles published by the National Board and you may want to see if Mr. Brown can help you in getting a copy of the group. The US Nuclear Regulatory Commission also issued a warning to owners of nuclear power plants (et. al.) that there was an issue with flanges made in China. It would certainly be of benefit to obtain a copy of this NRC document to reinforce your argument.

As I remember the incident (AND THIS IS JUST THE UNRELIABLE MEMORY OF AN OLD MAN), the incident resulted from a breakdown in communications. We (the international engineering community) have Codes and Standards in place that allow us to include commodity ("off the peg&quot pressure rated components (which comply to National or International consensus Standards) in our piping systems rather than designing them for each new system.

The US Standard for flanges is ANSI/ASME B16.5. At some point in time, some flanges were manufactured in China and imported by various Western countries (perhaps others). The Chinese manufacturers were PRESUMMABLY not aware of the B16.5 requirement that the flanges be forged, one-piece construction. Some of these flanges were manufactured by fabricating (welding)them. When these flanges were installed in piping systems and the systems were hydrostatically tested (150 times design pressure), the flanges failed. The National Board was informed of this and they investigated; also the NRC investigated. The government of China investigated (and as I remember, they rectified the problem). The reports of these investigations were issued and they tell the real story. I WOULD STRONGLY SUGGEST THAT ANYONE WHO WANTS AN ACCURATE DESCRIPTION OF THE INCIDENT OBTAIN COPIES OF THE REPORTS. Do not rely upon the account above as being completely true.

The Internet is a great source of information.

For a list of Welding research council bulletins see:

http://www.forengineers.org/pvrc.htm

For National Board of Boiler and Pressure Vessel Inspectors "Classic" series see:

http://www.nationalboard.org/Classics/category.html

For more piping, pressure vessel, and tank discussion boards see:

http://www.asme.org/bboard/challenge.tcl?topic=Pressure Vessel and Piping

and

http://www.coade.com/

Regards, John

 

Hello,

Sorry I got the web site address for Welding Research Council Bulletins wrong in the response above.

The correct web site address is:

http://www.forengineers.org/wrc/wrcpvrcbulletin.htm

Regards, John.

 

Hello,

I should not type before I have had my coffee. Yes, I know that hydrostatic testing is done at 150 percent of design pressure and not at 150 times design pressure. This was an inadvertance - sorry 'bout that.

Regards, John.