JIS Wafer Butterfly Valves (IMPA 75-22-08)

JIS wafer-type butterfly valves are the workhorse isolation valve on Japanese-built and Japanese-standard ships, used throughout seawater cooling, ballast and general service piping where a compact, quarter-turn valve fits between pipe flanges. The wafer body clamps between two flanges without its own flange drilling, which keeps it light and short, and it is operated by a lever for smaller sizes or a gearbox for larger bores. Under the IMPA Marine Stores Guide the standard JIS wafer butterfly valve sits at code 75-22-08, with the six-digit code resolving to a specific nominal bore — for example 150 mm — and body and disc material. The wear components are the seat liner, which provides the seal and is matched to the service fluid, and the disc and stem assembly. Because these valves sit in seawater and general-service systems, the seat elastomer must resist the carried fluid and the valve must match the existing flange standard and pressure class. Buyers source by IMPA code, nominal bore and operation type, and confirm the seat material against the service. This curated subtype page covers JIS wafer butterfly valve selection and the identifiers a purchaser needs to order the correct valve and seat for a piping replacement.