{"dataset":"Valve Seat Leakage Class Cross-Reference Dataset","id":"leakage-classes","description":"Documented seat leakage classes and rates across API 598, ISO 5208 and BS 6755, with numeric limits and measurement basis where the source standard defines them.","publisher":"Vajra Industrial Solutions","publisherUrl":"https://www.vajravyuh.com","sourcePage":"https://www.vajravyuh.com/resources/valve-leakage-class-reference","downloadUrl":"https://www.vajravyuh.com/data/leakage-classes.json","license":"Free to use with attribution to Vajra Industrial Solutions (vajravyuh.com)","citation":"Vajra Valve Data Commons - Leakage Class Cross-Reference Dataset, Vajra Industrial Solutions, vajravyuh.com/data","disclaimer":"Engineering reference data for valve service; indicative only. Ratings and limits depend on concentration, temperature and service conditions. Verify against the governing standard and a qualified engineer before procurement.","recordDescription":"One record per class/rate label within a standard.","fields":["standard","class","definition","numericLimit","basis","typicalUse"],"recordCount":8,"records":[{"standard":"API 598","class":"Class A","definition":"Zero leakage (bubble-tight)","numericLimit":null,"basis":null,"typicalUse":"Metal seats, safety valves"},{"standard":"API 598","class":"Class D","definition":"Soft-seat maximum leakage","numericLimit":"0.18 mL/min per NPS (for NPS ≤ 2\" liquid)","basis":"per NPS (inch, nominal pipe size)","typicalUse":"General soft-seated valves"},{"standard":"ISO 5208","class":"Rate A","definition":"Zero leakage — no measurable leakage","numericLimit":null,"basis":null,"typicalUse":"Gas and toxic fluid service"},{"standard":"ISO 5208","class":"Rate D","definition":"Standard rate for most industrial valves","numericLimit":null,"basis":null,"typicalUse":"General industrial valves"},{"standard":"BS 6755","class":"Rate A","definition":"Zero leakage (bubble-tight) at test pressure","numericLimit":null,"basis":null,"typicalUse":"Toxic, hazardous or zero-leakage applications"},{"standard":"BS 6755","class":"Rate B","definition":"Maximum leakage per unit nominal bore","numericLimit":"0.006 cm³/min per mm DN","basis":"per mm DN (metric, nominal diameter)","typicalUse":"Gas and vapour service"},{"standard":"BS 6755","class":"Rate C","definition":"Maximum leakage per unit nominal bore","numericLimit":"0.18 cm³/min per mm DN","basis":"per mm DN (metric, nominal diameter)","typicalUse":"General liquid service"},{"standard":"BS 6755","class":"Rate D","definition":"Maximum leakage per unit nominal bore","numericLimit":"1.8 cm³/min per mm DN","basis":"per mm DN (metric, nominal diameter)","typicalUse":"Lower-criticality liquid isolation duties"}],"undocumentedClassRanges":[{"standardSlug":"api-598","standardCode":"API 598","note":"API 598 also defines intermediate Classes B and C between A and D; their specific numeric leak rates are not recorded in this reference — consult API 598 directly."},{"standardSlug":"iso-5208","standardCode":"ISO 5208","note":"ISO 5208 defines Rates A through F (F = most relaxed); only Rates A and D have numeric definitions recorded here — consult ISO 5208 directly for B, C, E and F."}]}