The Valve,safety Relief, cataloged under National Stock Number 4820-01-180-8478, 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 12 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through both NSN and commercial part number lookups. 2 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 4820-01-180-8478 |
| Primary Part Number | 20257FM41M |
| 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 |
| Nominal Pipe Size Accommodated | 0.250 INCHES ALL ENDS IN |
| Connection Style | SOCKET WITH BRAZING RING ALL ENDS |
| Connection Type | UNTHREADED INTERNAL PIPE ALL ENDS |
| Style Designator | ANGLE |
| Operating Pressure | 1500.0 POUNDS PER SQUARE INCH (PSI) MAXIMUM SINGLE RESPONSE LBS |
| Adjustable Pressure Range | +535.0 TO 755.0 POUNDS PER SQUARE INCH LBS |
| Bonnet Type | INSIDE SCREW |
| Bonnet Attachment Method | BOLTED |
| Material | COPPER ALLOY BODY |
| Material | NICKEL ALLOY STEM |
| 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 |
|---|---|
| 20257FM41M PRIMARY | Emerson Automation Solutions Final Control Us Lp Div Navy Product Team (USA) |
| Reference | Meaning |
|---|---|
| 20257FM41M | 5/9 Secondary reference Anderson Greenwood Lp Dba Anderson Greenwood Crosby |
| 20257EM41M | C/1 Advisory reference — outside the item-of-supply concept Anderson Greenwood Lp Dba Anderson Greenwood Crosby |
NSN 4820-01-180-8478 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 4820-01-180-8478 has 1 manufacturer part number on file: 20257FM41M (Emerson Automation Solutions Final Control Us Lp Div Navy Product Team).
Key specifications for 20257FM41M: Flow Control Device: DISK; Nominal Pipe Size Accommodated: 0.250 INCHES ALL ENDS IN; Connection Style: SOCKET WITH BRAZING RING ALL ENDS; Connection Type: UNTHREADED INTERNAL PIPE ALL ENDS. 12 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.