BS EN 558:2017 pdf free.Industrial valves- Face-to-face and centre-to-face dimensions of metal valves for use in flanged pipe systems- PN and Class designated valves. BS EN 558 This European Standard specifies the "face-to-face" (FTF) and "centre-to-face" (CTF) dimensions for PN and Class designated metal valves used in flanged pipe systems.This European Standard covers valves with the following PN, Class and...