ASME Section III, Class 3 Valve W/ "N" Stamp 2

[Powerman81]

Hi,

I am working on a modification that requires the replacement of ASME Section III, Class 3 valve which requires the "N" stamp. The valve is needed for the upcoming outage that is 2 months from now. Unfortunately, the lead time for new valve is no less than 48 weeks. I am reaching out to other utilities to locate a valve that I can use. What I need to know is what process to I need to follow to qualify the new valve for my application and how long the process takes.

Thanks

 

[jpankask]

You need to provide the specifics of the needed valve to your plant's procurement department or procurement engineering. They can search other plants inventory or call plants to find a valve that may work. The valve they find will likely be certified to a different Code year than what you require and may even be of a different configuration than you currently have. Your engineering change process will need to address all of the differences in the valve and you will need to perform a Code reconciliation between the Code years in order to be able to use the valve.

Alternately, you may need to go with a different type of valve that your plant already has in stock, or different size. If you need a 2" gate valve, but you have a 3" gate valve in your warehouse, you could use that with a modification. There are lots of possibilities but valve companies just don't stock ASME valves on the shelf anymore. Worst case, you might need to temporarily use something else until you can get the proper original design valve delivered and then replace it again.

Also, there are companies you can order the valve from that will perform the required Code reconciliations, etc. for you. NLI is one company we use quite a bit. Structural Integrity Associates is another company that does Code reconciliation a lot.

 

[rcchap]

There is one other thing you need to be aware of. Specific requirements might have been originally specified for the valves used during construction of your plant (such as additional NDE or specific seismic accelerations). For a 2" valve, you probably have a small bore valve spec that was used, and you need to review that. If you get a valve out of stock from a different plant, it will probably not meet all these requirements. If it is a matter of reanalzying for different seismic accelerations, that is one thing. But the NDE requirements may be a show stopper, and these requirements may be difficult to waive.

All of this comes out when performing the code reconciliation, which is required per ASME Section XI IWA-4000. If you have never done one of these before, you will need help, and jpankask's recommendations above are good ones, but I am sure you have engineers at your plant who can also help.

BTW, I wouldn't recommend putting a 3" valve on a 2" line. You will have a "head scratcher" installed for the life of your plant. What I mean by that is that people will see the valve, stop and scratch their heads, and say "What idiot engineer did THAT?" Also, the additional weight would likely cause some piping analysis issues.

The best solution is to defer the mod to the following outage so you can get the proper valve.