UTG of Tank

Date 02-12-2008 18:02

Does the unit have an echo to echo setting? If it does I don't know of a reason why you couldn't use it. Unless the paint is to thick to read through. It's difficult getting a good signal with echo to echo sometimes.

By hogan

Date 02-12-2008 19:47

even without an echo to echo function on your machine you can perform thickness readings through paint. any a scan machine can be calibrated to give thickness readings minus the coating. the echo to echo seem to be user friendly for some.

By rafael Angarita (*)

Date 02-13-2008 11:38

You can do UT with coat of paint; calibrate the equipment considering coat thicness. The CWI that mades the test can do this, but is not a common practice because the coat thickness may influence on results. Better do test with out coat.

By krautkrammer (*)

Date 02-13-2008 13:59

thank you guys for the response,but the problem is we dont know the paint coating thickness (unless we used a DFT equipment), this things normally happen when doing a tank inspection which include a ultrasonic thickness gauging(UTG). The tank owner, don't require any grinding works on the surface of the shell plates especially when the tank is still in-service. What i need to know here is if there's a UTG equipment/machine out there that can be use on measuring the thickness of tank shell plates coated with paint which can measure only the base metal thickness(even with paint coating).

By hogan

Date 02-13-2008 15:14

By jmdugan10 (*)

Date 02-14-2008 14:10

The simple answer is yes there are machines out there that can do that. As stated previously any A-scan can do it even if it doesnt have an echo to echo feature. I didn't think of that before. I just automaticlly think echo to echo when reading through paint. If you remove the paint in a small area and take a UT reading then take a reading next to that on the paint, that will at least give you an idea of the thickness of the paint. That way you can calibrate for the paint thickness. I still think echo to echo is the way to go.

By Bill M

Date 02-14-2008 14:16

Can't you simply measure the coating thickness a number of places and come up with an average coating thickness value (using an appropriate coating thickness measurement device).

Then take all the material thickness measurements with the UT thickness gage and subtract the ave. coating thickness value from every reading?

By Joey

Date 02-14-2008 15:01

1st Question ; Answer is Yes , there are many brand. You may ask your sales agent to do the demonstration before you purchase one.

2nd Question : Answer is Yes. You may ask for UTG history / or ask for previous test report to compare your current readings on painted surfaces. You can take readings on same TMLs to compare your current reading. As per API 653, the number of thickness measurement locations is to be decided by Owner-user, hence, you can take more readings than usual for verification (if you're the owner user!). Remember to indicate in your UTG report the actual condition of the surface whether coated or not coated for future reference by next UT technicians.

If no previous UTG record, check the thickness stated on drawing / and find out the nominal thickness used from mill test cert in MDR.

Regards
Joey

By krautkrammer (*)

Date 02-16-2008 14:22

Thank you mr. joey for your response,,actually you have the same explanation with our API 653 inspector(my boss). The storage tank is first time to be inspected so we don't have any previous report to compare our current readings. We have the drawings but it shows that we got a higher readings, compare what were indicated on the drawings.We suspected that the material thickness used is different on what were indicated on the drawing or maybe the drawing is not updated(in terms of the actual material thickness used).

The UTG equipment we used only shows the thickness reading, it is not a flaw type ultrasonic testing equipment that's why echo to echo technique is not applicable.

Thank you to all!!

By Joey

Date 02-16-2008 17:16

just call me "Joey" ...i can be Ms. sometimes :=)

It was my experienced from working with API 653 inspector.

Regards
Joey

By krautkrammer (*)

Date 02-18-2008 05:41

Joey,

What part of asia you are working? because i'm working here in singapore?

regards,

Raymund

By Joey

Date 02-18-2008 10:48

Raymund

Places are Kuala Lumpur, Johor Bahru, Singapore, Jakarta, Batam, Manila, Makati, Batangas, Bicol, Bangkok, Hadjai...etc. I've been in ASIA to check our sub vendors' fabrication work or attend inspection during site installation of steel structures and refinery equipment.

I like Singapore...very clean and chewing gum is prohibited., I have few friends working there in BT Engineering.
Keep in touch Bro, I may visit you there one day.

Regards
Joey

By dlmann

Date 02-18-2008 17:40

Hello krautkrammer:
We use a panametrics MG2 with D7906-SM through coat transducer. Works well and have had no problems with it.
Regards, Donnie Mann

By krautkrammer (*)

Date 02-19-2008 07:31

Donnie Mann,

We used the Panametrics 26MG with the transducer D799.
Is the D799 a through coat transducer?

Thanks,

By krautkrammer (*)

Date 02-19-2008 08:39

hi donnei mann,

I found the answer on my question and i want to thank you for leading me there. I just search/browse the panametrics website and found the following;

MG2 series & 37DL - are the corrosion thickness gages that can be used on measuring metal thickness through paint.

Probes/transducers;
D790,D791,D797 & D798 -can be use for echo-to-echo measurement
D7906-SM or a D7908 - can be used on Thru-Coat measurement.

Thanks again donnei.!! you are the MAN(n)!! :-)