The Valve,safety Relief, cataloged under National Stock Number 4820-00-540-1872, is classified within Federal Supply Class 4820 (Valves, Nonpowered) of the Valves group. Government technical data includes 27 specifications, cited from the U.S. Government catalog. 4 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog.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 | 4820-00-540-1872 |
| Item Name | Valve,safety Relief |
| FSC / FSG | 4820 / 48 — Valves, Nonpowered |
| Status | ACTIVE |
| Flow Control Device | POPPET |
| Connection Style | GASKET SEAL(BOSS) SECOND END |
| Connection Style | FLARED (TUBE) FIRST END |
| Connection Type | THREADED EXTERNAL TUBE FIRST END |
| Connection Type | THREADED INTERNAL BOSS SECOND END |
| Style Designator | STRAIGHT THRU |
| Operating Pressure | 250.0 POUNDS PER SQUARE INCH (PSI) MAXIMUM SINGLE RESPONSE LBS |
| Features Provided | PRESSURE TIGHT OUTLET SIDE |
| Bonnet Type | PACKING RETAINING |
| Thread Direction | RIGHT-HAND SECOND END |
| Thread Direction | RIGHT-HAND FIRST END |
| Nominal Thread Size | 0.437 INCHES FIRST END IN |
| Nominal Thread Size | 0.548 INCHES SECOND END IN |
| Seat Angle | 37.0 DEGREES FIRST END |
| Maximum Operating Temp | 200.0 FAHRENHEIT SINGLE RESPONSE DEGF |
| Disk Loading Method | SPRING |
| Media for Which Designed | OIL, HYDRAULIC SINGLE RESPONSE |
| Thread Class | 3A FIRST END A |
| Thread Class | 3B SECOND END |
| Material | STEEL CORROSION RESISTING FLOW CONTROL DEVICE |
| Material | ALUMINUM BODY |
| Material | RUBBER SYNTHETIC SEAT |
| Thread Series Designator | UNIFIED NATIONAL JOINT FINE (UNJF) SECOND END |
| Thread Series Designator | UNF FIRST END |
| Opening Pressure Setting | 105.0 POUNDS PER SQUARE INCH LBS |
| Valve Discharge Flow Rate | 1.0 GALLONS PER MINUTE |
| 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 |
|---|---|
| 4446441-105PS1 | 5/2 Secondary reference U.S. Government activity |
| 4446441-501 | 5/2 Secondary reference U.S. Government activity |
| 2R1450 | 3/2 Design control — primary reference U.S. Government activity |
| 4446441-501 | 5/9 Secondary reference The Boeing Company |
NSN 4820-00-540-1872 is a Valve,safety Relief, classified under FSC 4820, Valves, Nonpowered. Status: active.
Key specifications for 4820-00-540-1872: Flow Control Device: POPPET; Connection Style: GASKET SEAL(BOSS) SECOND END; Connection Style: FLARED (TUBE) FIRST END; Connection Type: THREADED EXTERNAL TUBE FIRST END. 27 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.