Okay, I think what you are asking is 'how far apart at a minimum must two separate weld joints be?' So, you have two circumferential welds on 30" X .500 wall pipe and need to know how far apart the applicable code says they must be spaced? Right?
First, if the engineer, or manufacturer/owner on the project, has accepted D1.1 welder qualifications, even a welder qualified to a plate test would be qualified. Anything over 24" can be qualified by plate.
Now, vague as my memory is on things API and ASME I believe that this question has arisen many times on the forum and could probably be found using the 'search' function. But, I'm sure some of the pipe guys will be along to correct me if I misspeak my opinion of your query.
As I recall the discussions, and as far as D1.1 goes, there is nothing in the codes that dictate a set distance nor formula to determine distance between joints.
While there may be practical and even metallurgical reasons for such separation, it is a question left to the specific engineers on the job to determine if they want any particular space between joints.
As with many other issues, there are wives tales and rules of thumb abounding on what the spacing should be. I believe in this case it is normally considered to be a multiple of the diameter of the pipe, either 1 1/2 X or 2 1/2 X , again from my poor memory. So with your 30" pipe it would be between 45" and 75" for a MINIMUM according to a rule of thumb. But, rules of thumb have no bearing in codes. It is either in the code or it is not. As far as I know, especially for D1.1, it is NOT.
The other perspective that you could be referring to is how to align the seam welds for offset from one section to the next so that they are not in line which would lend itself to an extended inline weakness. I don't believe that is in the codes either. Again, there are rules of thumb and standard practices by some companies but nothing called out in the codes. You will often see 1/3 offsets. Sometimes other ratios. But nothing code wise as far as I recall.
He Is In Control, Have a Great Day, Brent
Regarding the publications you've listed, I doubt you will fing any info. If there is such a requirement it is usually in the owners QC. Offsets of 1/4 diameter are common. No seam on the bottom quarter due to that is where any oil/sludge from compression processes can cause internal corrosion is a common requirement. ASME IV - Low pressure Heating boilers, were you thinking of VIII?
D1.1 (2010) 5.22.3.1, also says longitudinal weld seams shall be staggered at least 90°, unless closer spacing is agreed upon by the owner and fabricator.
I seem to nail pile drivers all the time on that one.