The present standard gives a selection of external diameters and thicknesses of tubes according to ISO 2964. These tubes shall be used for conveying fluids such as kerosen, oil, air, etc… for engine application.
AECMA PREN 3717-1991 history
1991AECMA PREN 3717-1991 Aerospace Series Tubes Selection for Engines Fluid Systems Issue P 1
1990AECMA PREN 3717-1990 Aerospace Series Tubes, Selection and Tolerances for Engines Fluid Systems Edition 1; Supersedes C8