The Valve,safety Relief, cataloged under National Stock Number 4820-01-321-1790, is classified within Federal Supply Class 4820 (Valves, Nonpowered) of the Valves group. The manufacturer of record is Emerson Automation Solutions Final Control Us Lp Div Navy Product Team. Government technical data includes 28 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through both NSN and commercial part number lookups. 3 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 4820-01-321-1790 |
| Primary Part Number | NMP121-3/4IN-L2122C-200 PSI |
| Item Name | Valve,safety Relief |
| FSC / FSG | 4820 / 48 — Valves, Nonpowered |
| Manufacturer | Emerson Automation Solutions Final Control Us Lp Div Navy Product Team |
| Status | ACTIVE |
| Flow Control Device | DISK |
| Flange Shape | ROUND WITH HOLES FIRST END |
| Nominal Pipe Size Accommodated | 0.750 INCHES SECOND END IN |
| Flange Face Design | PLAIN FIRST END |
| Connection Style | SOCKET SECOND END |
| Bolt Circle Nominal Diameter | 3.188 INCHES FIRST END IN |
| Connection Type | UNTHREADED INTERNAL PIPE SECOND END |
| Connection Type | FLANGE FIRST END |
| Style Designator | ANGLE |
| Bolt Hole Nominal Diameter | 0.562 INCHES FIRST END IN |
| Operating Pressure | 200.0 POUNDS PER SQUARE INCH (PSI) MAXIMUM SECOND RESPONSE LBS |
| Operating Pressure | 400.0 POUNDS PER SQUARE INCH (PSI) MAXIMUM FIRST RESPONSE LBS |
| Bonnet Type | INSIDE SCREW |
| Maximum Operating Temp | 425.0 FAHRENHEIT SECOND RESPONSE DEGF |
| Maximum Operating Temp | 150.0 FAHRENHEIT FIRST RESPONSE DEGF |
| Nominal Outside Diameter | 4.312 INCHES FIRST END IN |
| Bolt Hole Quantity | 4 FIRST END |
| Bonnet Attachment Method | THREADED |
| Media for Which Designed | STEAM SECOND RESPONSE |
| Media for Which Designed | WATER, FRESH THIRD RESPONSE |
| Media for Which Designed | AIR FIRST RESPONSE |
| Material | BRONZE BODY |
| Material | NICKEL ALLOY SEAT |
| Material | BRONZE FLOW CONTROL DEVICE |
| Material | COPPER ALLOY STEM |
| Opening Pressure Setting | 200.0 POUNDS PER SQUARE INCH LBS |
| Valve Operation Method | AUTOMATIC |
| Nominal Thickness | 0.688 INCHES FIRST END IN |
| 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 |
|---|---|
| NMP121-3/4IN-L2122C-200 PSI PRIMARY | Emerson Automation Solutions Final Control Us Lp Div Navy Product Team (USA) |
| Reference | Meaning |
|---|---|
| NMP121-3/4IN-L2122C-200 PSI | 5/9 Secondary reference Anderson Greenwood Lp Dba Anderson Greenwood Crosby |
| NMP121-3/4IN-L2 | C/1 Advisory reference — outside the item-of-supply concept Kunkle Industries Inc Lonergan Valve Div |
| NMP121-3/4IN-L2122C-200 PSI | 5/9 Secondary reference Kunkle Industries Inc Lonergan Valve Div |
NSN 4820-01-321-1790 is a Valve,safety Relief, manufactured by Emerson Automation Solutions Final Control Us Lp Div Navy Product Team, classified under FSC 4820, Valves, Nonpowered. Status: active.
NSN 4820-01-321-1790 has 1 manufacturer part number on file: NMP121-3/4IN-L2122C-200 PSI (Emerson Automation Solutions Final Control Us Lp Div Navy Product Team).
Key specifications for NMP121-3/4IN-L2122C-200 PSI: Flow Control Device: DISK; Flange Shape: ROUND WITH HOLES FIRST END; Nominal Pipe Size Accommodated: 0.750 INCHES SECOND END IN; Flange Face Design: PLAIN FIRST END. 28 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.