A - little or no action B - moderate action C - strong action S - unknown FLUID OR MATERIAL CONVEYED NR NBR EPDM HYPALON® Fatty acids C B/C C C Ferric bromide A S A A Ferric chloride A A A A Ferric nitrate A A A A Ferric sulfate A A A A Ferrous acetate C S B C Ferrous chloride A A A A Ferrous hydroxide B/C S A/B B Ferrous sulfate A A/B A A Fluoboric acid B S A A Fluorine gas C C C C Fluorobenzene S S S S Fluosilicic acid B S A A Formaldehyde B C S A Formalin B S A A Formic acid B S A B Freon 12 C S C C Freon 22 C C C C Freon SO2 S S S S Fuel B (ASTM) C A C C Fuel C (ASTM) C A C C Fuel oil C A C C Furan C C C C Furfural C C C S Furfuryl alcohol C C C S