The Valve,safety Relief, cataloged under National Stock Number 4820-00-956-0641, is classified within Federal Supply Class 4820 (Valves, Nonpowered) of the Valves group. The manufacturer of record is Curtiss-Wright Electro-Mechanical Corp Dba Steam & Air Solutions Div Curtiss-Wright Steam and Air Solutions. Government technical data includes 15 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through both NSN and commercial part number lookups. 5 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 4820-00-956-0641 |
| Primary Part Number | MLW125496G1 |
| Item Name | Valve,safety Relief |
| FSC / FSG | 4820 / 48 — Valves, Nonpowered |
| Manufacturer | Curtiss-Wright Electro-Mechanical Corp Dba Steam & Air Solutions Div Curtiss-Wright Steam and Air Solutions |
| Status | ACTIVE |
| Flow Control Device | DISK |
| Nominal Pipe Size Accommodated | 0.500 INCHES FIRST END IN |
| Connection Style | PLAIN (PIPE) FIRST END |
| Connection Type | THREADED EXTERNAL PIPE FIRST END |
| Style Designator | ANGLE |
| Operating Pressure | 3000.0 POUNDS PER SQUARE INCH (PSI) MAXIMUM SINGLE RESPONSE LBS |
| Bonnet Type | INSIDE SCREW |
| Thread Direction | RIGHT-HAND FIRST END |
| Nominal Thread Size | 0.500 INCHES FIRST END IN |
| Bonnet Attachment Method | THREADED |
| Material | STEEL BODY |
| Material | STEEL SEAT |
| Thread Series Designator | NPT FIRST END |
| Opening Pressure Setting | 3500.0 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 |
|---|---|
| MLW125496G1 PRIMARY | Curtiss-Wright Electro-Mechanical Corp Dba Steam & Air Solutions Div Curtiss-Wright Steam and Air Solutions (USA) |
| Reference | Meaning |
|---|---|
| 3W28577T3 | 5/9 Secondary reference Ingersoll Rand Co |
| MLW125496G1 | 3/9 Design control — primary reference Siemens Energy, Inc. Dba Dresser-Rand |
| MLW125496G1 | 5/9 Secondary reference U.S. Government activity |
| 3W28577T3 | 5/9 Secondary reference U.S. Government activity |
| MLW125496G1 | 5/9 Secondary reference Curtiss-Wright Electro-Mechanical Corporation Dba Curtiss-Wright Steam and Air Solutions Div Steam and Air Solutions |
NSN 4820-00-956-0641 is a Valve,safety Relief, manufactured by Curtiss-Wright Electro-Mechanical Corp Dba Steam & Air Solutions Div Curtiss-Wright Steam and Air Solutions, classified under FSC 4820, Valves, Nonpowered. Status: active.
NSN 4820-00-956-0641 has 1 manufacturer part number on file: MLW125496G1 (Curtiss-Wright Electro-Mechanical Corp Dba Steam & Air Solutions Div Curtiss-Wright Steam and Air Solutions).
Key specifications for MLW125496G1: Flow Control Device: DISK; Nominal Pipe Size Accommodated: 0.500 INCHES FIRST END IN; Connection Style: PLAIN (PIPE) FIRST END; Connection Type: THREADED EXTERNAL PIPE FIRST END. 15 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.