It is acceptable when the TOTAL length of the cracks does not exceed 1/8 inches (3.2 mm).
Example:
There are three cracks each measuring 1 mm, so the total length will be 3 mm, less than 3.2 mm or 1/8 inches. Acceptable.
There are three cracks each measuring 1.5 mm, so the toal length will be 4.5 mm, more than 3.2 or 1/8 inches. Not acceptable.
If there are cracks, it's advisable to observe them by means of a magnifying lens.
Giovanni S. Crisi
Sao Paulo - Brazil
I normally agree with Mr. Crisi, but in this case disagree. The code is silent on cumulative length being a factor in the acceptance criteria. Thus, my opinion is that it doesn't matter with respect to the code.
Our company imposes more resrictive criteria than the code in cases like this. We only allow a maximum of five indications and the combined length (using the max dimension of each indication) may not exceed 3/8".
Other companies we have had experience with set even tougher acceptance criteria. Whenever that is the case, we have never argued the point as we generally are attempting to gain them as clients.
Charles
I read it like Charles.
1104 uses the term "aggregate length", and that isn't used here.
We've done quite a bit of work under the API 1104 code over the years, and I don't know of anybody that adheres stricktly to it, The gas/oil companies imposes harsher criteria than what the code calls for in every case I know of. Meaning that even if the code allows it, I don't know of and have never heard of anyplace a welder could pass a test with three cracks in a strap.
JTMcC.
Beg your pardon, Gentlemen, I was thinking of ASME IX.
The API 1104 I've got on hand in this moment says that the total length of cracks must not exceed the smaller of the following figures:
- one half of an inch
- one eigth of an inch plus the pipe thickness.
The mistake is corrected.
Giovanni S. Crisi
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