The Valve,safety Relief, cataloged under National Stock Number 4820-01-284-4242, is classified within Federal Supply Class 4820 (Valves, Nonpowered) of the Valves group. The manufacturer of record is Naval Inventory Control Point Mechanicsburg. Government technical data includes 21 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through both NSN and commercial part number lookups. 2 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 4820-01-284-4242 |
| Primary Part Number | 9979B51MCP |
| Item Name | Valve,safety Relief |
| FSC / FSG | 4820 / 48 — Valves, Nonpowered |
| Manufacturer | Naval Inventory Control Point Mechanicsburg |
| Status | ACTIVE |
| Flow Control Device | DISK |
| Furnished Items and Quantity | 2 TAILPIECE AND 1 PLUGGED DRAIN AND 1 WRENCH |
| Nominal Pipe Size Accommodated | 1.250 INCHES FIRST END IN |
| Nominal Pipe Size Accommodated | 0.375 INCHES SECOND END IN |
| Connection Style | SOCKET WITH BRAZING RING ALL ENDS |
| Criticality Code Justification | ZZZY |
| Connection Type | UNTHREADED INTERNAL PIPE ALL ENDS |
| Style Designator | ANGLE |
| Material Document and Classification | ASTM B61 ASSN STD SINGLE MATERIAL RESPONSE BODY |
| 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 |
| Operating Pressure | 3000.0 POUNDS PER SQUARE INCH (PSI) MAXIMUM SINGLE RESPONSE LBS |
| Adjustable Pressure Range | +1401.0 TO 1800.0 POUNDS PER SQUARE INCH LBS |
| Maximum Operating Temp | 150.0 FAHRENHEIT SINGLE RESPONSE DEGF |
| Disk Loading Method | SPRING |
| Material | NICKEL ALLOY 400 OR NICKEL ALLOY R-405 STEM |
| Material | NICKEL ALLOY 400 OR NICKEL ALLOY R-405 SEAT |
| Material | COPPER ALLOY 922 BODY |
| Opening Pressure Setting | 1401.0 POUNDS PER SQUARE INCH LBS |
| Valve Operation Method | MANUAL |
| Reference Number Differentiating Characteristics | CLEANING, PACKAGING, AND MARKING IAW THE LATEST REVISION OF MIL-STD-1330 |
| 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 |
|---|---|
| 9979B51MCP | Naval Inventory Control Point Mechanicsburg (USA) |
| Reference | Meaning |
|---|---|
| 9979B51M | 3/1 Design control — primary reference Emerson Automation Solutions Final Control Us Lp Div Navy Product Team |
| 9979B51M | 5/9 Secondary reference Anderson Greenwood Lp Dba Anderson Greenwood Crosby |
NSN 4820-01-284-4242 is a Valve,safety Relief, manufactured by Naval Inventory Control Point Mechanicsburg, classified under FSC 4820, Valves, Nonpowered. Status: active.
NSN 4820-01-284-4242 has 1 manufacturer part number on file: 9979B51MCP (Naval Inventory Control Point Mechanicsburg).
Key specifications for 9979B51MCP: Flow Control Device: DISK; Furnished Items and Quantity: 2 TAILPIECE AND 1 PLUGGED DRAIN AND 1 WRENCH; Nominal Pipe Size Accommodated: 1.250 INCHES FIRST END IN; Nominal Pipe Size Accommodated: 0.375 INCHES SECOND END IN. 21 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.