The Valve,safety Relief, cataloged under National Stock Number 4820-01-256-3582, is classified within Federal Supply Class 4820 (Valves, Nonpowered) of the Valves group. Government technical data includes 19 specifications, cited from the U.S. Government catalog. 4 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 4820-01-256-3582 |
| Item Name | Valve,safety Relief |
| FSC / FSG | 4820 / 48 — Valves, Nonpowered |
| Status | ACTIVE |
| Flow Control Device | POPPET |
| Connection Style | PLAIN (TUBE) ALL ENDS |
| Connection Type | THREADED EXTERNAL TUBE ALL ENDS |
| Style Designator | STRAIGHT THRU |
| Operating Pressure | 200.0 POUNDS PER SQUARE INCH (PSI) MAXIMUM SINGLE RESPONSE LBS |
| Thread Direction | RIGHT-HAND ALL ENDS |
| Nominal Thread Size | 0.437 INCHES ALL ENDS IN |
| Maximum Operating Temp | 400.0 FAHRENHEIT SECOND RESPONSE DEGF |
| Maximum Operating Temp | -100.0 FAHRENHEIT FIRST RESPONSE DEGF |
| Media for Which Designed | NITROGEN, GASEOUS FIFTH RESPONSE |
| Media for Which Designed | HYDROGEN FOURTH RESPONSE |
| Media for Which Designed | HELIUM THIRD RESPONSE |
| Media for Which Designed | CARBON DIOXIDE SECOND RESPONSE |
| Media for Which Designed | AIR FIRST RESPONSE |
| Thread Class | 3A ALL ENDS A |
| Material | ALUMINUM ALLOY BODY |
| Thread Series Designator | UNIFIED NATIONAL JOINT FINE (UNJF) ALL ENDS |
| Opening Pressure Setting | 28.0 POUNDS PER SQUARE INCH LBS |
| Valve Operation Method | AUTOMATIC |
| Acquisition Status | ACTIVE |
| DEMIL Code | DEMIL A — No Demilitarization Required |
| Hazard | No hazard code in the DLA record (HMIC N) |
| Criticality Code | X |
| Reference | Meaning |
|---|---|
| Z02RV04A280S | 5/2 Secondary reference U.S. Government activity |
| 524A-4D-28 | 3/2 Design control — primary reference U.S. Government activity |
| Z02RV04A280S | 5/9 Secondary reference Zevco Inc |
| 412732 | 7/1 Vendor item drawing reference U.S. Government activity |
NSN 4820-01-256-3582 is a Valve,safety Relief, classified under FSC 4820, Valves, Nonpowered. Status: active.
Key specifications for 4820-01-256-3582: Flow Control Device: POPPET; Connection Style: PLAIN (TUBE) ALL ENDS; Connection Type: THREADED EXTERNAL TUBE ALL ENDS; Style Designator: STRAIGHT THRU. 19 specifications are documented in the U.S. Government catalog.
No hazard code in the DLA record (HMIC N). Hazard information on this page is shown exactly as it appears in the DLA record.
U.S. Government catalog: edition PUBLOGDVD v12.0.0 (OCT 2026), edition date 2026-10-01, retrieved 2026-10-16.
U.S. Government catalog: edition PUBLOGDVD v12.0.0 (OCT 2026), edition date 2026-10-01, retrieved 2026-10-18.