— mm
MINIMUM — your pipe's MEASURED wall must be at least this thick.
Anything thicker is fine; it is a floor, not a size.
Nominal is not measured. The tube standards themselves allow the wall to
run under nominal — EN 10219-2 and EN 10210-2 −10%, EN 10255
−10% welded and −12,5% seamless, EN ISO 1127 −7,5% to
−15% by class. Work to the standard your pipe is made to, or measure it.
Same figure on the drawing and in the pack.