The Valve,safety Relief, cataloged under National Stock Number 4820-00-421-5869, is classified within Federal Supply Class 4820 (Valves, Nonpowered) of the Valves group. The manufacturer of record is Northrop Grumman Systems Corporation. Government technical data includes 22 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through both NSN and commercial part number lookups. 3 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. 1 item shares a part number with this NSN in the catalog (possible match — not a government interchangeability claim). Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 4820-00-421-5869 |
| Primary Part Number | A51H9032-1 |
| Item Name | Valve,safety Relief |
| FSC / FSG | 4820 / 48 — Valves, Nonpowered |
| Manufacturer | Northrop Grumman Systems Corporation |
| Status | ACTIVE |
| Flow Control Device | DIAPHRAGM |
| Connection Style | EXTERNAL SEAT FOR GASKET SEAL (BOSS) FIRST END |
| Connection Type | THREADED EXTERNAL BOSS FIRST END |
| Style Designator | ANGLE |
| Nominal Outside Diameter Tube Accommodated | 0.250 INCHES FIRST END IN |
| Bonnet Type | PACKING RETAINING |
| Thread Direction | RIGHT-HAND FIRST END |
| Nominal Thread Size | 0.437 INCHES FIRST END IN |
| Maximum Operating Temp | 330.0 FAHRENHEIT SINGLE RESPONSE DEGF |
| Disk Loading Method | SPRING |
| Surface Treatment | PAINT AND PRIMER LOCATION NOT OTHERWISE SPECIFIED |
| Media for Which Designed | NITROGEN, GASEOUS SECOND RESPONSE |
| Media for Which Designed | AIR FIRST RESPONSE |
| Thread Class | 3A FIRST END A |
| Thread Quantity Per Inch | 20 FIRST END |
| Material | STEEL COMP 630 BODY |
| Material | STEEL COMP 630 SEAT |
| Material | COPPER ALLOY 170 FLOW CONTROL DEVICE |
| Thread Series Designator | UNF FIRST END |
| Opening Pressure Setting | 4500.0 POUNDS PER SQUARE INCH LBS |
| Valve Discharge Flow Rate | 15.0 CUBIC FEET 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 |
| Part Number | Manufacturer |
|---|---|
| A51H9032-1 | Northrop Grumman Systems Corporation (USA) |
| Reference | Meaning |
|---|---|
| 34670-3 | 3/2 Design control — primary reference U.S. Government activity |
| A51H9032-1 | 5/9 Secondary reference Northrop Grumman Systems Corporation |
| A51H9032-1 | 5/9 Secondary reference Northrop Grumman Systems Corporation Dba Northrop Grumman Systems Corp Div Northrop Grumman Aeronautics Systems |
NSN 4820-00-421-5869 is a Valve,safety Relief, manufactured by Northrop Grumman Systems Corporation, classified under FSC 4820, Valves, Nonpowered. Status: active.
NSN 4820-00-421-5869 has 1 manufacturer part number on file: A51H9032-1 (Northrop Grumman Systems Corporation).
1 possible match (shared part number, not a government interchangeability claim): 2815-01-311-4006. Verify interchangeability with system specifications before substitution.
Key specifications for A51H9032-1: Flow Control Device: DIAPHRAGM; Connection Style: EXTERNAL SEAT FOR GASKET SEAL (BOSS) FIRST END; Connection Type: THREADED EXTERNAL BOSS FIRST END; Style Designator: ANGLE. 22 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.