Surface Finish Requirements Surface Finish Code BPE Designation Inside Surface Outside Surface Ra Max. Polish Method Polish Method μ-in. μm PU SF0 Unpolished Unpolished PC SF1 20 0.51 Mechanical Polish Unpolished PL SF1 20 0.51 Mechanical Polish Mechanical Polish (32Ra) PD SF4 15 0.38 Mechanical Polish & Electropolish Unpolished. SF1 20 0.51 SF1 20 0.51 ... grade and the surface finish designation, or material identification number, depending on the size of the fitting. These numbers allow complete traceability of all component material back to the original material supplier. Material Test Reports (MTR) will be supplied on request. Please specify at time of order if. The pharmaceutical industry as well as components of a distribution system or conveyor belts, have an established guideline for their surface finish requirements called ASME-BPE. ASME-BPE is the leading Standard on how to design and build equipment and systems used in the production of biopharmaceuticals, which includes bioprocessing. "/>Sf1 surface finish