The Valve,safety Relief, cataloged under National Stock Number 4820-01-516-3833, is classified within Federal Supply Class 4820 (Valves, Nonpowered) of the Valves group. The manufacturer of record is Curtiss-Wright Flow Control Corporation Dba Farris Engineering Div Curtiss-Wright Valves Division- Farris. 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 | 4820-01-516-3833 |
| Primary Part Number | 646B-3-3/8-2 |
| Item Name | Valve,safety Relief |
| FSC / FSG | 4820 / 48 — Valves, Nonpowered |
| Manufacturer | Curtiss-Wright Flow Control Corporation Dba Farris Engineering Div Curtiss-Wright Valves Division- Farris |
| Status | ACTIVE |
| Connection Style | PLAIN,OPTIONAL END(PIPE) SECOND END |
| Connection Style | PLAIN (PIPE) FIRST END |
| Minimum Operating Temp | -40.0 FAHRENHEIT DEGF |
| Connection Type | THREADED INTERNAL PIPE SECOND END |
| Connection Type | THREADED EXTERNAL PIPE FIRST END |
| Style Designator | ANGLE |
| Adjustable Pressure Range | +40.0 TO 125.0 POUNDS PER SQUARE INCH LBS |
| Thread Direction | RIGHT-HAND SECOND END |
| Thread Direction | RIGHT-HAND FIRST END |
| Nominal Thread Size | 0.3750 INCHES FIRST END IN |
| Nominal Thread Size | 0.3750 INCHES SECOND END IN |
| Maximum Operating Temp | 250.0 FAHRENHEIT SINGLE RESPONSE DEGF |
| Disk Loading Method | SPRING |
| Material | STEEL COMP 303 BODY |
| Thread Series Designator | NPT SECOND END |
| Thread Series Designator | NPT FIRST END |
| 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 |
|---|---|
| 646B-3-3/8-2 PRIMARY | Curtiss-Wright Flow Control Corporation Dba Farris Engineering Div Curtiss-Wright Valves Division- Farris (USA) |
NSN 4820-01-516-3833 is a Valve,safety Relief, manufactured by Curtiss-Wright Flow Control Corporation Dba Farris Engineering Div Curtiss-Wright Valves Division- Farris, classified under FSC 4820, Valves, Nonpowered. Status: active.
NSN 4820-01-516-3833 has 1 manufacturer part number on file: 646B-3-3/8-2 (Curtiss-Wright Flow Control Corporation Dba Farris Engineering Div Curtiss-Wright Valves Division- Farris).
Key specifications for 646B-3-3/8-2: Connection Style: PLAIN,OPTIONAL END(PIPE) SECOND END; Connection Style: PLAIN (PIPE) FIRST END; Minimum Operating Temp: -40.0 FAHRENHEIT DEGF; Connection Type: THREADED INTERNAL PIPE SECOND END. 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.