The Valve,safety Relief, cataloged under National Stock Number 4820-01-279-2983, is classified within Federal Supply Class 4820 (Valves, Nonpowered) of the Valves group. The manufacturer of record is Fluid Mechanics Valve Company. Government technical data includes 17 specifications, cited from the U.S. Government catalog. The record lists 1 manufacturer part number for this item, enabling identification through both NSN and commercial part number lookups. Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 4820-01-279-2983 |
| Primary Part Number | 42502-3310 |
| Item Name | Valve,safety Relief |
| FSC / FSG | 4820 / 48 — Valves, Nonpowered |
| Manufacturer | Fluid Mechanics Valve Company |
| Status | ACTIVE |
| Flow Control Device | DISK |
| Connection Style | GASKET SEAL(BOSS) ALL ENDS |
| Connection Type | THREADED INTERNAL BOSS ALL ENDS |
| Style Designator | ANGLE |
| Operating Pressure | 3000.0 POUNDS PER SQUARE INCH (PSI) MAXIMUM SINGLE RESPONSE LBS |
| Thread Direction | RIGHT-HAND ALL ENDS |
| Nominal Thread Size | 0.750 INCHES SECOND END IN |
| Nominal Thread Size | 1.062 INCHES FIRST END IN |
| Disk Loading Method | SPRING |
| Thread Class | 3B ALL ENDS |
| Thread Quantity Per Inch | 12 FIRST END |
| Material | COPPER ALLOY BODY |
| Material | PLASTIC POLYTETRAFLUOROETHYLENE SEAT |
| Thread Series Designator | UN FIRST END |
| Thread Series Designator | UNF SECOND END |
| Opening Pressure Setting | 660.0 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 |
| Part Number | Manufacturer |
|---|---|
| 42502-3310 PRIMARY | Fluid Mechanics Valve Company (USA) |
NSN 4820-01-279-2983 is a Valve,safety Relief, manufactured by Fluid Mechanics Valve Company, classified under FSC 4820, Valves, Nonpowered. Status: active.
NSN 4820-01-279-2983 has 1 manufacturer part number on file: 42502-3310 (Fluid Mechanics Valve Company).
Key specifications for 42502-3310: Flow Control Device: DISK; Connection Style: GASKET SEAL(BOSS) ALL ENDS; Connection Type: THREADED INTERNAL BOSS ALL ENDS; Style Designator: ANGLE. 17 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.