Good point of "want to know the truth" aspect. An ultrasound is only as accurate as the person taking it. When you look at a cut out pc of firebox or barrel for that matter, you see only what you see. Much like an ultra sound taken in the middle of a 4" square may not tell the whole truth of the corrosion or thickness. The pictures above say volumes. Much like doing a biopsy looking for cancer. If you hit healthy tissue your biopsy is going to show you your good to go. On the bottom of that organ or two inches over you may have serious problems that can kill you if not taken care of.

At one museum who had two boilers under repair at the same time had different approaches. One boiler was ultrasounded 3x by 3 different people with 3 sets of different results. Eventually a volunteer was getting some scary numbers and wasn't sure what was going on. I was told that the steel was de-laminating/separating and he was finding those spots? I was not involved and this was what was my understanding. The entire firebox was gutted including the crown sheet which up till that time was considered ok? Think this, was in the end the best thing that could of happen, but that was after a lot of money had been stuck into that firebox. We all learn from our mistakes, and we all make them.

The other privately owned boiler had a professional ultra sound done by a NDT company out of Neenah Wi {I think}. Same things still applies to how good a job that company person did? But they gave a detailed engineering style report that looked good when handed in. THis company specialized in NDT. That boiler passed every FRA inspection with flying colors and is operating still. Though next year the ticket is up I think? Later on when we went into that boiler and major repairs were being made, we found some sadness that we were originally unaware of and then those repairs were made as well. The ultrasound is not the end all testing to determine your boilers health that is for sure. It is a start maybe. In my not so humble opinion based on my experiences. Regards, John.

When we did the UT inspection on 4-6-2 S.P. 2472's boiler about 20 years ago, we hired a UT expert to train our volunteers in where to inspect, and how to prep the surfaces to inspect. A lot of the work is laying out the grid on the boiler shell, prepping the spots to inspect, and recording the measurements.

- Doug Debs

As a follow up to my previous comment, and photo:

Today the Nevada Northern posted this photo on Facebook. Notice that the UT transducer marks are just above, and immediately adjacent to the staybolts. The work has been performed above the running board.

Read the regulation:49 CFR 230.32(b) Method of inspection —

(1) Entire boiler. During the 1472 service day inspection, the entire boiler shall be examined for cracks, pitting, grooving, or indications of overheating and for damage where mud has collected, or heavy scale formed. The edges of plates, all laps, seams, and points where cracks and defects are likely to develop, shall be thoroughly inspected. Rivets shall be inspected for corrosion and looseness.

If you use ultrasonic testing, do not limit it to just thickness testing in a grid pattern in general, seek out the cracks, pitting and grooving as per the regulation. Yes this requires some research to find where and how to locate the defects.

Question for discussion, how big of a pit (in area) that is below minimum thickness is acceptable if the rest of the component has sufficient thickness or does that pit automatically condemn that component of the boiler?
Mike Tillger

Sometimes you can drill and tap a pit or defect, then screw a plug into it, and be all right with the world again... except when you can't.

Wouldn't say condemn, but certainly any rational person would want to effect a repair since they don't tend to regrow missing metal in service, including any marginal areas adjacent to the defect.

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Can someone from ASR give us a detailed methodology and perhaps pictures of the recent NDT that was done on 2100's boiler? That would be a good example of up-to-date modern practice.

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I'm curious. Does the FRA require any level of competence in this area? My employers do quite a bit of NDE and the technicians have to be certified and have many years of experience. They call it Non Destructive Examination as "Testing" implies more . As an example a hydrostatic test shows that a vessel actually will hold a stated pressure where as an ultrasound shows thickness in that exact spot.

Hello Again,

Kelly was correct, my original post was directed toward generating some conversation regarding the UT examinations of boilers for the 1472 inspections.

There have been some very interesting comments.

Would like to mention a few items that seem important to the work:

      It is most important to have a calibration block (specimen) of the same type of material being examined. The block is used often to verify the machine and transducer are reading correctly.

      Strict attention should be paid to battery life on the machine. As the battery loses its strength, readings become more inconsistent. Another reason for frequent use of the calibration block.

      Surface preparation is, again, quite important. This can be accomplished quite well using a fine grit "flapper wheel". Taking a reading through a rough surface will not produce accurate results.

Below are two sites that provide good information on the how and why of the discipline.

https://en.wikipedia.org/wiki/Ultrasoni ... easurement

https://www.olympus-ims.com/en/applicat ... s-gauging/
An Introduction to Ultrasonic Thickness Gauging
ndt, panametrics-ndt, non destructive test equipment, ultrasonic transducers, ultrasonic sensors, non destructive testing, nondestructive testing, ultrasonic testing, gauge thickness, ultrasonic thickness measurements, crack detection, flaw meter, ultrasonic inspection, flaws detection, flaw theory, NDT theory, ultrasonic flaw detection
http://www.olympus-ims.com
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The information provided by Mr. Jordan is most informative and important......................thank you, Sir!!

Hoping this has been productive for all.

Respectfully,

Dave Griner