The Valve,safety Relief, cataloged under National Stock Number 4820-01-481-7638, is classified within Federal Supply Class 4820 (Valves, Nonpowered) of the Valves group. Government technical data includes 15 specifications, cited from the U.S. Government catalog. 1 additional reference document (drawings, advisory and superseded references) is recorded in the U.S. Government catalog. Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 4820-01-481-7638 |
| Item Name | Valve,safety Relief |
| FSC / FSG | 4820 / 48 — Valves, Nonpowered |
| Status | ACTIVE |
| Flow Control Device | POPPET |
| Connection Style | PLAIN,OPTIONAL END(PIPE) SECOND END |
| Connection Style | PLAIN (PIPE) FIRST END |
| Connection Type | THREADED INTERNAL PIPE SECOND END |
| Connection Type | THREADED EXTERNAL PIPE FIRST END |
| Style Designator | STRAIGHT THRU NOTE: TO BE USED FOR VALVE BODIES OF ONE SECTION ONLY. |
| Operating Pressure | 3000.0 POUNDS PER SQUARE INCH (PSI) MAXIMUM SINGLE RESPONSE LBS |
| Thread Direction | RIGHT-HAND ALL ENDS |
| Nominal Thread Size | 0.250 INCHES ALL ENDS IN |
| Maximum Operating Temp | 121.0 CELSIUS SINGLE RESPONSE DEGC |
| Material | COPPER ALLOY 360 FLOW CONTROL DEVICE |
| Material | RUBBER BUTADIENE-ACRYLONITRILE CLASS NBR PACKING |
| Material | COPPER ALLOY 345 OR COPPER ALLOY 360 BODY |
| Thread Series Designator | NPT ALL ENDS |
| 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 |
|---|---|
| B-4CP6-1/3 | 3/9 Design control — primary reference Nupro Co |
NSN 4820-01-481-7638 is a Valve,safety Relief, classified under FSC 4820, Valves, Nonpowered. Status: active.
Key specifications for 4820-01-481-7638: Flow Control Device: POPPET; Connection Style: PLAIN,OPTIONAL END(PIPE) SECOND END; Connection Style: PLAIN (PIPE) FIRST END; Connection Type: THREADED INTERNAL PIPE SECOND END. 15 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.