UT (Keypoints) Reference Point

[InspectionSoftware]

I am presently writing a procedure for UT Wall Thickness Reference Points.

Searching the web and professional sites, I couldn't find any documentation on this subject.

I have asked many large Oil/Gas Operators if they had a draft of any sort procedure - None seem to exist!!?

OK So I have a 4" pipe that is 200 metres in length - How many UT points should be checked ? Obviously, using the 12,3,6,9 O'clock positions. Does any have any reference standards?

OSP


Dr. Ransom stated that 'Eldil' didn't exist. But we saw them in 'Out of the Silent'.

 

[dcasto]

Here's my opinion.
1) Taking too much data and you have a nice random number generator.
2) what makes you think you will find the spot where the mill defect is or the spot corrosion is?

It isn't the number of data points that count, its the location you select on the piece of pipe.

We've set up a table of the number of data points. Based on the following: Risk assement of the line which is probability of failure due to corrosive service vs severity of promblem if the line failed. Next we start with 5 point, then add points based on risk, lenght, 90's, low point, dead leags, ect. Then we train our people where the corrosion should be and start with those points to fill in the dtat point. In plant line will have from 5 to 15.

IF you want exact data, they make tools that clamp on the outside of lines and will give you 10,000 points at every angle, no need to do UT, the tool does it.

 

[sms]

I don't know of a standard off the top of my head, but there might be one in the Nuclear business. More likely than Oil and Gas anyway...

Back in the early 80's I did a couple projects in feedwater systems for Nuke plants. We looked at lines with wall thinning due to two phase flow. In that case we drew grids on the elbows with 1 inch spacing, and then went every foot or so down the straight run and took a sample with 1 inch spacing all the way around the pipe. That was 10" pipe and bigger..

What exactly are you looking for? That will probably decide your spacing...


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[Heckler]

Here is a link.

http://www.ndt.net/article/wcndt00/papers/idn713/idn713.htm

I think it would depend on what your contract states as far as testing the wall thickness of the pipe.

Heckler
Sr. Mechanical Engineer
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[InspectionSoftware]

Thanks for the comments guys!
To expand further I am looking for a procedure for UT Reference Points on Straight Pipe/Pipeworks. As stated by (DCASTO) Elbows, lows, etc are obvious UT Points

Whilst I appreciate that product, system, and risk are all variables in the selection of UT Points, there must be a basic standard that co relates to the length and dia of the pipe?

(SMS) mention that the Nuclear Industry might have a procedure?

Dr. Ransom stated that 'Eldil' didn't exist. But we saw them in 'Out of the Silent'.