Live monitoring of crack on equipment

[vesselguy]

Hi all,

I don't have much operating experience so I would like to get some input from those of you who are in facilities engineering. Is there a way to live monitor cracking of the bottom shell to floor joint on a storage tank. If this can be done effectively then an owner can minimize the amount of entry into a tank for checking this joint.

The only live checking of cracks I know of is acoustic emission. But this technique is labor intensive and not suited for automated everyday live monitoring.

 

[Bonswa]

What's the product? Why would you need LIVE monitoring? Acoustic Emmission is the only test that comes to mind. I've asked before about using acoustic emissions on pressure vessels and piping in caustic and amine type services as a constant automatic monitor.

I dont think it's truly necessary for a storage tank, unless its under some type of pressure. If it's atmospheric, and you're that worried about it, you should just schedule an Acoustic Emission contractor to come out and perform the inspection on a routine basis. Monthly, perhaps, would suffice.

 

[vesselguy]

Bonswa,

This is just a general question. Someone asked me this few months ago and I don't know of anyother method except for accoustic emission. I just like to have an answer for my own knowledge. That client's operator is thinking of ways to reduce man entry to a tank to check for integrety of the "T" weld joint there.

 

[Bonswa]

Are they currently on some type of schedule to enter this tank and check those "T" welds? If so, do you know how often?

Reason I ask is because it's not required, by API-653 for them to frequently enter this tank and check those "T" junctions. The client may have their own procedure though. If it's in some type of service with cracking as one of the damage mechanisms, then you should just perform magnetic particle testing on those welds during your NORMAL out-of-service inspection interval (20 years max).

Back to what I said before. If you wanted to do something ON-stream to check for cracking, there's nothing PERMANENT. You would have to have someone come in periodically to perform Acoustic Emission testing or Shear Wave. The client could put that in their monitoring program or schedule. The client could put AE testing or UT shear wave testing on a set interval and continuously monitor it.