BS EN ISO 27509:2020 pdf free.Petroleum and natural gas industries —Compact flanged connections with IX seal ring. BS EN ISO 27509 This document specifies detailed manufacturing requirements for circular steel and nickel alloy compact flanged connections and associated seal rings, for designated pressures and temperatures in class designations CL 150 (PN 20> to CL 1500 (PN 260> for nominal sizes...