The Valve,safety Relief, cataloged under National Stock Number 4820-01-481-1838, 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 13 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through both NSN and commercial part number lookups. 2 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. 1 item shares a part number with this NSN in the catalog (possible match — not a government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 | 4820-01-481-1838 |
| Primary Part Number | 8573B51M |
| 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 |
| Flange Shape | ROUND WITH HOLES ALL ENDS |
| Furnished Items and Quantity | 1 WRENCH |
| Nominal Pipe Size Accommodated | 0.500 INCHES ALL ENDS IN |
| Connection Type | FLANGE ALL ENDS |
| Operating Pressure | 150.0 POUNDS PER SQUARE INCH (PSI) MAXIMUM SINGLE RESPONSE LBS |
| Adjustable Pressure Range | +10.0 TO 14.0 POUNDS PER SQUARE INCH LBS |
| Bonnet Type | INSIDE SPRING |
| Maximum Operating Temp | 150.0 FAHRENHEIT SINGLE RESPONSE DEGF |
| Disk Loading Method | SPRING |
| Bonnet Attachment Method | BOLTED |
| Media for Which Designed | AIR FIRST RESPONSE |
| Media for Which Designed | WATER, FRESH SECOND RESPONSE |
| 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 |
|---|---|
| 8573B51M PRIMARY | Emerson Automation Solutions Final Control Us Lp Div Navy Product Team (USA) |
| Reference | Meaning |
|---|---|
| 8573 | D/9 Drawing number reference only Anderson Greenwood Lp Dba Anderson Greenwood Crosby |
| 8573B51M | 5/9 Secondary reference Anderson Greenwood Lp Dba Anderson Greenwood Crosby |
NSN 4820-01-481-1838 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 4820-01-481-1838 has 1 manufacturer part number on file: 8573B51M (Emerson Automation Solutions Final Control Us Lp Div Navy Product Team).
1 possible match (shared part number, not a government interchangeability claim): 4820-01-683-4405. Verify interchangeability with system specifications before substitution.
Key specifications for 8573B51M: Flange Shape: ROUND WITH HOLES ALL ENDS; Furnished Items and Quantity: 1 WRENCH; Nominal Pipe Size Accommodated: 0.500 INCHES ALL ENDS IN; Connection Type: FLANGE ALL ENDS. 13 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.