AutoCAD MEP

[#1]

What can I do to export a PCF file from Autocad MEP 2013 for creating pipe construction Isometric drawings with Isometrics WS?

The only way is to re-draw the pipe line created with MEP in Plant 3D? Anyway, does Plant 3D accept the MEP part catalog?

[#2]

You will have to redraw in plant 3D.  I am not familiar with Plant 3D but I am about 99.9 percent positive that it cannot load an Autocad MEP catalog.  Autocad MEP 2013 did introduce a universal connector that will allow you to connect to plant 3d piping though.  Not much of help to you though.  :-(