This Standard specifies stainless steel threaded fittings (hereafter referred to "fittings") used for ordinary piping for steam, air, gas, water, oil, etc.
JIS B 2308:2013 Referenced Document
ISO 6708:1995 Pipework components - Definition and selection of DN (nominal size)
JIS B 0151 Iron and steel pipe fittings -- Vocabulary*, 2018-03-20 Update