On the actual MLP itself, LH2 Side 4 the transfer (white) line is about 10in diameter. the vent (grey) line is 12in if I remember correctly. On the LOX (side 2) side, i believe the transfer line is 8, the vent is 10
thanks for your information and the great photos, I am pleased that you announced yourself. I found in the meantime some informations about the MLP LOX/LH2 pipes and also diameters in the STS-111 FLIGHT READINESS REVIEW.
Afterwards it is to concern double-walled pipes with the diameters of the H2 Vent Line: 14'' x 16'' on Side 4 and 10'' x 12'' on Side 1 to Valve Skid (Presenter: Brad McCain)
For my MLP build I only need the outside diameters. If I convert the diameters from your 2nd photo, I come on 15'' for the transfer line (white) and 17'' for the vent line (grey) on Side 1 right beside the LH2 Valve Skid.
What do you think of my method? So I could determine myself also the diameters of the lines on Side 2 and to the left of the LOX Valve Skid.