B31.1

By LCMP Date 04-13-2006 11:56

I have a question for all you more experienced hands. I'm recently moved over from NDE to a QC Manager position, and ever since I've been here, I've felt like I'm in a little over my head!

Anyway, here is the question. When referencing B31.1 table 136.4 (NDE requirements) are the thicknesses in the second column based on single or double wall? furthermore, is weld reinforcement included?

Any help would be greatly appreciated!

By MNSTRBLDR (**)

Date 04-13-2006 15:28

My guess is that it is for single wall, and the thickness should be only the wall thickness of the pipe. I don't believe it includes the weld. I am a new Q.C. myself, but that's the way I read it. I don't see any notes to say other wise. I'm sure there are alot more experienced people in here to answer your question, but that's the way I read it. Hope this helps.

By NDTIII

Date 04-13-2006 17:42

The thicknesses in the column you are referring to are nominal single wall thicknesses.
Reinforcement shall be no more than that permittted by Table 127.4.2.
To answer your question, yes reinforement may be included for determining IQI requirements.
For radiography, your IQI shall be based on the single wall thickness plus the maximm reinforcement permitted by the referencing code.
That means if Table 127.4.2 permit 1/16" reinforcement, that means 1/16" for each face of the weld. Root and cap.
Generally the IQI is based on the thickness of the area of interest, which in this case is the weld.

By LCMP Date 04-14-2006 19:10

Thanks for the info. I knew it worked that way for the IQI (I'm an ex RT hand myself) but wasn't sure if it applied when selecting whether or not the piece would be inspected.

Again thanks, and I'm sure you'll see my postings here in the future!

By NDTIII

Date 04-15-2006 05:41

Yes, that's exactly what that table is for. It tells you that different types of welds over a given design temperature and pressure require inspection. All welds require visual.
For example if you have a girth weld in a 3" pipe and it is designed for temperatures over 750 degrees F, it gets RT or UT. If it is NPS (Nominal Pipe Size) 2" or less, it gets PT or MT. However, if you look at Note 2, it may recieve RT in lieu of MT or PT.