The Valve,safety Relief, cataloged under National Stock Number 4820-00-166-8791, 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 26 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through both NSN and commercial part number lookups. 4 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. 2 items share a part number with this NSN in the catalog (possible match — not a government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 | 4820-00-166-8791 |
| Primary Part Number | 20274K51MC1D883116768 |
| 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 |
| Furnished Items and Quantity | 2 NUT AND 1 LEVER AND 2 TAILPIECE |
| Nominal Pipe Size Accommodated | 0.500 INCHES ALL ENDS IN |
| Connection Style | SOCKET ALL ENDS |
| Connection Type | UNTHREADED INTERNAL PIPE ALL ENDS |
| Style Designator | ANGLE |
| Material Document and Classification | QQ-N-281 FED SPEC 1ST MATERIAL RESPONSE OR QQ-N-288 FED SPEC 2ND MATERIAL RESPONSE SEAT |
| Material Document and Classification | QQ-N-281 FED SPEC 1ST MATERIAL RESPONSE OR QQ-N-288 FED SPEC 2ND MATERIAL RESPONSE BODY |
| Material Document and Classification | QQ-N-281 FED SPEC 1ST MATERIAL RESPONSE OR QQ-N-288 FED SPEC 2ND MATERIAL RESPONSE STEM |
| Operating Pressure | 400.0 POUNDS PER SQUARE INCH (PSI) MAXIMUM SINGLE RESPONSE LBS |
| Adjustable Pressure Range | +46.0 TO 72.0 POUNDS PER SQUARE INCH LBS |
| Features Provided | PRESSURE TIGHT OUTLET SIDE |
| Bonnet Type | INSIDE SPRING |
| Specification/standard Data | 81349-MIL-V-22549 GOVERNMENT SPECIFICATION |
| Maximum Operating Temp | 400.0 FAHRENHEIT SINGLE RESPONSE DEGF |
| Disk Loading Method | SPRING |
| Bonnet Attachment Method | THREADED |
| Media for Which Designed | AIR SINGLE RESPONSE |
| Test Data Document | 81349-MIL-S-901 SPECIFICATION (INCLUDES ENGINEERING TYPE BULLETINS, BROCHURES,ETC., THAT REFLECT SPECIFICATION TYPE DATA IN SPECIFICATION FORMAT; EXCLUDES COMMERCIAL CATALOGS, INDUSTRY DIRECTORIES, AND SIMILAR TRADE PUBLICATIONS, REFLECTING GENERAL TYPE DATA ON CERTAIN ENVIRONMENTAL AND PERFORMANCE REQUIREMENTS AND TEST CONDITIONS THAT ARE SHOWN AS "TYPICAL", "AVERAGE", "NOMINAL", ETC.). |
| Material | NICKEL ALLOY STEM |
| Material | NICKEL ALLOY SEAT |
| Material | NICKEL ALLOY BODY |
| Material | NICKEL ALLOY AND PLASTIC POLYTETRAFLUOROETHYLENE FLOW CONTROL DEVICE |
| Opening Pressure Setting | 72.0 POUNDS PER SQUARE INCH LBS |
| Valve Discharge Flow Rate | 101.0 CUBIC FEET PER MINUTE |
| 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 |
|---|---|
| 20274K51MC1D883116768 PRIMARY | Emerson Automation Solutions Final Control Us Lp Div Navy Product Team (USA) |
| Reference | Meaning |
|---|---|
| 20274K51M | C/1 Advisory reference — outside the item-of-supply concept Anderson Greenwood Lp Dba Anderson Greenwood Crosby |
| MIL-V-22549 | 4/1 Identification reference U.S. Government activity |
| 20274K51MC1D883116768 | 5/9 Secondary reference Anderson Greenwood Lp Dba Anderson Greenwood Crosby |
| MIL-V-22549G1-2 400-46T072SBU | 5/1 Secondary reference Naval Inventory Control Point Mechanicsburg |
NSN 4820-00-166-8791 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 4820-00-166-8791 has 1 manufacturer part number on file: 20274K51MC1D883116768 (Emerson Automation Solutions Final Control Us Lp Div Navy Product Team).
2 possible matches (shared part number, not a government interchangeability claim): 4820-01-061-1507, 4820-01-279-5112. Verify interchangeability with system specifications before substitution.
Key specifications for 20274K51MC1D883116768: Flow Control Device: DISK; Furnished Items and Quantity: 2 NUT AND 1 LEVER AND 2 TAILPIECE; Nominal Pipe Size Accommodated: 0.500 INCHES ALL ENDS IN; Connection Style: SOCKET ALL ENDS. 26 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.