The Valve,safety Relief, cataloged under National Stock Number 4820-01-181-8635, 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 27 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through both NSN and commercial part number lookups. 2 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. 2 items share a part number with this NSN in the catalog (possible match — not a government interchangeability claim). Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 4820-01-181-8635 |
| Primary Part Number | E8573D51M50 |
| 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 ALL ENDS |
| Flange Face Design | PLAIN ALL ENDS |
| Bolt Circle Nominal Diameter | 2.438 INCHES ALL ENDS IN |
| Connection Type | FLANGE ALL ENDS |
| Style Designator | ANGLE FLANGED ENDS |
| Material Document and Classification | QQ-N-281 FED SPEC SINGLE MATERIAL RESPONSE FLOW CONTROL DEVICE |
| Material Document and Classification | QQ-N-281 FED SPEC SINGLE MATERIAL RESPONSE STEM |
| Material Document and Classification | QQ-N-281 FED SPEC SINGLE MATERIAL RESPONSE SEAT |
| Material Document and Classification | ASTM B-61 ASSN STD SINGLE MATERIAL RESPONSE BODY |
| Bolt Hole Nominal Diameter | 0.563 INCHES ALL ENDS IN |
| Operating Pressure | 150.0 POUNDS PER SQUARE INCH (PSI) MAXIMUM SINGLE RESPONSE LBS |
| Valve Size | 0.500 INCHES IN |
| Adjustable Pressure Range | +20.0 TO 24.0 POUNDS PER SQUARE INCH LBS |
| Maximum Operating Temp | 150.0 FAHRENHEIT SINGLE RESPONSE DEGF |
| Second Connection Face to Centerline Distance | 3.000 INCHES IN |
| Nominal Outside Diameter | 3.563 INCHES ALL ENDS IN |
| Bolt Hole Quantity | 3 ALL ENDS |
| Media for Which Designed | AIR FIRST RESPONSE |
| Media for Which Designed | WATER, FRESH SECOND RESPONSE |
| First Connection Face to Centerline Distance | 3.000 INCHES IN |
| Material | NICKEL ALLOY STEM |
| Material | NICKEL ALLOY FLOW CONTROL DEVICE |
| Material | NICKEL ALLOY SEAT |
| Material | COPPER ALLOY 922 BODY |
| Valve Operation Method | AUTOMATIC |
| Nominal Thickness | 0.375 INCHES ALL ENDS 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 |
|---|---|
| E8573D51M50 PRIMARY | Emerson Automation Solutions Final Control Us Lp Div Navy Product Team (USA) |
| Reference | Meaning |
|---|---|
| E8573D51M50 | 5/9 Secondary reference Anderson Greenwood Lp Dba Anderson Greenwood Crosby |
| 8573 | D/9 Drawing number reference only Anderson Greenwood Lp Dba Anderson Greenwood Crosby |
NSN 4820-01-181-8635 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 4820-01-181-8635 has 1 manufacturer part number on file: E8573D51M50 (Emerson Automation Solutions Final Control Us Lp Div Navy Product Team).
2 possible matches (shared part number, not a government interchangeability claim): 7310-01-367-9532, 4820-01-481-1838. Verify interchangeability with system specifications before substitution.
Key specifications for E8573D51M50: Flow Control Device: DISK; Flange Shape: ROUND WITH HOLES ALL ENDS; Flange Face Design: PLAIN ALL ENDS; Bolt Circle Nominal Diameter: 2.438 INCHES ALL ENDS IN. 27 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.