The Valve,safety Relief, cataloged under National Stock Number 4820-00-287-4644, 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 19 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through both NSN and commercial part number lookups. 13 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. 1 item shares a part number with this NSN in the catalog (possible match — not a government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 | 4820-00-287-4644 |
| Primary Part Number | FIG1251 1/2IN |
| 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 |
| Renewable Seat Ring Type | THREADED |
| Connection Style | SOCKET (TUBE) ALL ENDS |
| Connection Type | UNTHREADED INTERNAL TUBE ALL ENDS |
| Style Designator | ANGLE |
| Nominal Outside Diameter Tube Accommodated | 0.500 INCHES ALL ENDS IN |
| Operating Pressure | 400.0 POUNDS PER SQUARE INCH (PSI) MAXIMUM SECOND RESPONSE LBS |
| Operating Pressure | 200.0 POUNDS PER SQUARE INCH (PSI) MAXIMUM FIRST RESPONSE LBS |
| Adjustable Pressure Range | +136.0 TO 169.0 POUNDS PER SQUARE INCH LBS |
| Maximum Operating Temp | 425.0 FAHRENHEIT FIRST RESPONSE DEGF |
| Maximum Operating Temp | 150.0 FAHRENHEIT SECOND RESPONSE DEGF |
| Disk Loading Method | SPRING |
| Media for Which Designed | WATER-OIL-GAS SECOND RESPONSE |
| Media for Which Designed | STEAM FIRST RESPONSE |
| Material | COPPER ALLOY BODY |
| Material | NICKEL ALLOY FLOW CONTROL DEVICE |
| Material | NICKEL ALLOY SEAT |
| Material | COPPER 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 |
|---|---|
| FIG1251 1/2IN PRIMARY | Emerson Automation Solutions Final Control Us Lp Div Navy Product Team (USA) |
| 20058Q51M PRIMARY | Emerson Automation Solutions Final Control Us Lp Div Navy Product Team (USA) |
| Reference | Meaning |
|---|---|
| S4824H3163773PC1T018 | 3/1 Design control — primary reference Naval Sea Systems Command |
| 3076-10ALT10PCV49 | 5/9 Secondary reference U.S. Government activity |
| 1806CCU | 5/1 Secondary reference Ashcroft Inc Dba Heise |
| 5119-4824-3801PC1T0-16 | 5/1 Secondary reference Naval Sea Systems Command |
| FIG1251 1/2IN | 5/9 Secondary reference Anderson Greenwood Lp Dba Anderson Greenwood Crosby |
| 5119-4824-3801PC1T0-16 | 5/9 Secondary reference U.S. Government activity |
| 5119-4824-3801PC1T016 | 5/9 Secondary reference U.S. Government activity |
| R6309HHPC1T016 | 5/1 Secondary reference Ashcroft Inc Dba Heise |
| 20058Q51M | 5/9 Secondary reference Anderson Greenwood Lp Dba Anderson Greenwood Crosby |
| S4824H3163773PC1T018 | 5/9 Secondary reference U.S. Government activity |
| 1806 1-2-136-169 | 5/1 Secondary reference Ashcroft Inc Dba Heise |
| 5119-4824-3801PC1T016 | 5/1 Secondary reference Naval Sea Systems Command |
| K1-4900-1000250ALT10PC49 | 5/1 Secondary reference U.S. Government activity |
NSN 4820-00-287-4644 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 4820-00-287-4644 has 2 manufacturer part numbers on file: FIG1251 1/2IN (Emerson Automation Solutions Final Control Us Lp Div Navy Product Team), 20058Q51M (Emerson Automation Solutions Final Control Us Lp Div Navy Product Team).
1 possible match (shared part number, not a government interchangeability claim): 4820-00-289-3863. Verify interchangeability with system specifications before substitution.
Key specifications for FIG1251 1/2IN: Flow Control Device: DISK; Renewable Seat Ring Type: THREADED; Connection Style: SOCKET (TUBE) ALL ENDS; Connection Type: UNTHREADED INTERNAL TUBE ALL ENDS. 19 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.