if it’s still a nurbs pipe you’re lucky - go into edit buttons and press “UV Orco”. this means, when you map a texture using Orco (in the material buttons) it will be mapped using the original Uv coordinates of the nurbs object. nurbs objects have “implicit” UV-coordinates. (nurbs ALWAYS consist of cross-sections with four sides - this makes them less flexible then polygons, but easier to texture).
if you already converted hte pipe to a mesh, … delete it and make it again, it’s less time consuming than UV mapping the poly-pipe