I used an average 40ft "double joint" length and rounded up a bit.
Pass thickness varies by rod diameter, weld technique and groove angle(s).
Considering XL83NL question, I might have been too fast choosing 3.5mm, being too liberal for the bevel geometry for this rather thick pipe. This weld will be pretty wide at the outside surface. It should have a compound bevel, reducing the OD width, but avg pass thickness may turn out to be even less. 3.5mm works OK for estimating pipelines, usually having thinner walls, in the 5-10mm range.
So let's take a closer look.
Adjusting for weld groove angle on each pipe end, typ plain 30° bevels, or compound bevels,
This "single bevel" chart says that my number of passes estimate of 10, only works for 2x30° bevels when wall thickness is around 0.5" (12mm) or less. Hence XL83NL's concern. For the 33mm (1-3/8") thickness and estimating for a compound bevel,.. could be 15x2 =30 passes ?? Can it be 15hrs? XL83NL, is that what you were thinking.