The Valve,safety Relief, cataloged under National Stock Number 4820-00-772-3191, is classified within Federal Supply Class 4820 (Valves, Nonpowered) of the Valves group. The manufacturer of record is Essex Industries, Inc. Dba Essex Industries. Government technical data includes 25 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through both NSN and commercial part number lookups. 1 additional reference document (drawings, advisory and superseded references) is recorded in the U.S. Government catalog. Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 4820-00-772-3191 |
| Primary Part Number | K1221-8-9 |
| Item Name | Valve,safety Relief |
| FSC / FSG | 4820 / 48 — Valves, Nonpowered |
| Manufacturer | Essex Industries, Inc. Dba Essex Industries |
| Status | ACTIVE |
| Flow Control Device | POPPET |
| Connection Style | FLARED (TUBE) SECOND END |
| Connection Style | FLARED (TUBE) FIRST END |
| Connection Type | THREADED EXTERNAL TUBE FIRST END |
| Connection Type | THREADED EXTERNAL TUBE SECOND END |
| Style Designator | STRAIGHT THRU |
| Nominal Outside Diameter Tube Accommodated | 0.625 INCHES FIRST END IN |
| Nominal Outside Diameter Tube Accommodated | 0.500 INCHES SECOND END IN |
| Adjustable Pressure Range | +4.0 TO 6.0 POUNDS PER SQUARE INCH LBS |
| Features Provided | PRESSURE TIGHT OUTLET SIDE |
| Thread Direction | RIGHT-HAND SECOND END |
| Thread Direction | RIGHT-HAND FIRST END |
| Nominal Thread Size | 0.750 INCHES SECOND END IN |
| Nominal Thread Size | 0.875 INCHES FIRST END IN |
| Seat Angle | 37.0 DEGREES FIRST END |
| Seat Angle | 37.0 DEGREES SECOND END |
| Disk Loading Method | SPRING |
| Thread Class | 3A FIRST END A |
| Thread Class | 3A SECOND END A |
| Thread Quantity Per Inch | 16 SECOND END |
| Thread Quantity Per Inch | 14 FIRST END |
| Thread Series Designator | UNF FIRST END |
| Thread Series Designator | UNF SECOND END |
| Valve Discharge Flow Rate | 6.5 GALLONS 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 |
|---|---|
| K1221-8-9 PRIMARY | Essex Industries, Inc. Dba Essex Industries (USA) |
| Reference | Meaning |
|---|---|
| 4025T84P01 | 1/2 Source control — Government-approved source U.S. Government activity |
NSN 4820-00-772-3191 is a Valve,safety Relief, manufactured by Essex Industries, Inc. Dba Essex Industries, classified under FSC 4820, Valves, Nonpowered. Status: active.
NSN 4820-00-772-3191 has 1 manufacturer part number on file: K1221-8-9 (Essex Industries, Inc. Dba Essex Industries).
Key specifications for K1221-8-9: Flow Control Device: POPPET; Connection Style: FLARED (TUBE) SECOND END; Connection Style: FLARED (TUBE) FIRST END; Connection Type: THREADED EXTERNAL TUBE FIRST END. 25 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.