The Valve,safety Relief, cataloged under National Stock Number 4820-01-256-8527, 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 6 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. 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 | 4820-01-256-8527 |
| Primary Part Number | 203579940M |
| 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 |
| Criticality Code Justification | FEAT |
| Style Designator | ANGLE |
| Material Document and Classification | QQ-N-281,CLASS A FED SPEC 1ST MATERIAL RESPONSE OR QQ-N-281 CLASS B FED SPEC 2ND MATERIAL RESPONSE BODY |
| Operating Pressure | 6800.0 POUNDS PER SQUARE INCH (PSI) MAXIMUM SINGLE RESPONSE LBS |
| Media for Which Designed | OXYGEN, GASEOUS SINGLE RESPONSE |
| Material | NICKEL ALLOY 400 OR NICKEL ALLOY R-405 BODY |
| Acquisition Status | ACTIVE |
| DEMIL Code | DEMIL A — No Demilitarization Required |
| Hazard | No hazard code in the DLA record (HMIC N) |
| Criticality Code | S |
| Part Number | Manufacturer |
|---|---|
| 203579940M PRIMARY | Emerson Automation Solutions Final Control Us Lp Div Navy Product Team (USA) |
| 203579940MCP | Naval Inventory Control Point Mechanicsburg (USA) |
NSN 4820-01-256-8527 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 4820-01-256-8527 has 2 manufacturer part numbers on file: 203579940M (Emerson Automation Solutions Final Control Us Lp Div Navy Product Team), 203579940MCP (Naval Inventory Control Point Mechanicsburg).
1 possible match (shared part number, not a government interchangeability claim): 4820-01-270-6204. Verify interchangeability with system specifications before substitution.
Key specifications for 203579940M: Criticality Code Justification: FEAT; Style Designator: ANGLE; Material Document and Classification: QQ-N-281,CLASS A FED SPEC 1ST MATERIAL RESPONSE OR QQ-N-281 CLASS B FED SPEC 2ND MATERIAL RESPONSE BODY; Operating Pressure: 6800.0 POUNDS PER SQUARE INCH (PSI) MAXIMUM SINGLE RESPONSE LBS. 6 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.