Centre to centre distance between two nozzles lying on a blind

[Someone11]

Can anyone please tell me where shall I find the requirement for the minimum centre to centre distance between two nozzles lying on a blind? I have a blind flange of 24" Raised Face. Above this blind, there are three nozzles: two of 2" size and one of 4" size. While running this on pv elite, the error is given saying:
" 4.5.13 spacing violation detected between : Nozzle 'A' and Nozzle 'B'.
The Centerline Dist. is 8.00 while the sum of the ins. Radii is 9.25

4.5.13 spacing violation detected between : Nozzle 'B' and Nozzle 'C'.
The Centerline Dist. is 8.00 while the sum of the ins. Radii is 9.25 "
I am running the analysis using Codecase 2695. I am not understanding how the software is calculating the value 9.25??

 

[XL83NL]

Is this for an VIII-1 vessel? If so, it seems UG-39 is appropriate.

 

[Soft2008]

@aadya,
From your query, I presume you added insulation to your nozzle cylinder OD which cause interfere. (sum of the ins. Radii means insulation radius of nozzle A and nozzle B ?)
please check if your nozzle was added insulation, and if insulation is necessary, consider to avoid the overlap of each nozzle's insulation.