The Valve,safety Relief, cataloged under National Stock Number 4820-00-168-1741, is classified within Federal Supply Class 4820 (Valves, Nonpowered) of the Valves group. The manufacturer of record is Northrop Grumman Systems Corporation Dba Electronic Systems. Government technical data includes 11 specifications, cited from the U.S. Government catalog. The record lists 2 manufacturer part numbers for this item, enabling identification through both NSN and commercial part number lookups. 1 additional reference document (drawings, advisory and superseded references) is recorded in the U.S. Government catalog. Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 4820-00-168-1741 |
| Primary Part Number | 990C843801 |
| Item Name | Valve,safety Relief |
| FSC / FSG | 4820 / 48 — Valves, Nonpowered |
| Manufacturer | Northrop Grumman Systems Corporation Dba Electronic Systems |
| Status | ACTIVE |
| Flow Control Device | DISK |
| Connection Style | EXTERNAL SEAT FOR GASKET SEAL (BOSS) FIRST END |
| Connection Type | THREADED EXTERNAL BOSS FIRST END |
| Style Designator | STRAIGHT THRU W/BAFFLE |
| Thread Direction | RIGHT-HAND FIRST END |
| Nominal Thread Size | 0.750 INCHES FIRST END IN |
| Thread Class | 2A FIRST END A |
| Material | STEEL CORROSION RESISTING FLOW CONTROL DEVICE |
| Material | ALUMINUM BODY |
| Thread Series Designator | UNF 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 |
|---|---|
| 990C843801 | Northrop Grumman Systems Corporation Dba Electronic Systems (USA) |
| 990C843H01 | Northrop Grumman Systems Corporation Dba Electronic Systems (USA) |
| Reference | Meaning |
|---|---|
| D513A8D41 | 3/2 Design control — primary reference U.S. Government activity |
NSN 4820-00-168-1741 is a Valve,safety Relief, manufactured by Northrop Grumman Systems Corporation Dba Electronic Systems, classified under FSC 4820, Valves, Nonpowered. Status: active.
NSN 4820-00-168-1741 has 2 manufacturer part numbers on file: 990C843801 (Northrop Grumman Systems Corporation Dba Electronic Systems), 990C843H01 (Northrop Grumman Systems Corporation Dba Electronic Systems).
Key specifications for 990C843801: Flow Control Device: DISK; Connection Style: EXTERNAL SEAT FOR GASKET SEAL (BOSS) FIRST END; Connection Type: THREADED EXTERNAL BOSS FIRST END; Style Designator: STRAIGHT THRU W/BAFFLE. 11 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.