Please define "bubble-tight" service when we have butterfly valves. Does this apply only to ANSI rated high performance valves or does resilient seated valves also have such a rating?
"Bubble tight" means zero leakage. Second question -- no, not only ANSI high performance valves. Resilient seated valves are typically soft seated and as a result bubble tight. See ANSI FCI 70-2 for additional information. All Flo-Tite valves are tested to MSS SP-72 at 100 psi under water in Open and Closed positions.