The Valve,safety Relief, cataloged under National Stock Number 4820-01-187-6822, is classified within Federal Supply Class 4820 (Valves, Nonpowered) of the Valves group. The manufacturer of record is Hydrasearch Company, Llc. Government technical data includes 19 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through both NSN and commercial part number lookups. 5 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 4820-01-187-6822 |
| Primary Part Number | 6VR57-4-3 |
| Item Name | Valve,safety Relief |
| FSC / FSG | 4820 / 48 — Valves, Nonpowered |
| Manufacturer | Hydrasearch Company, Llc |
| Status | ACTIVE |
| Flow Control Device | DISK |
| Connection Style | PLAIN (PIPE) ALL ENDS |
| Connection Type | THREADED EXTERNAL PIPE ALL ENDS |
| Style Designator | ANGLE |
| Operating Pressure | 6000.0 POUNDS PER SQUARE INCH (PSI) MAXIMUM SINGLE RESPONSE LBS |
| Features Provided | PRESSURE TIGHT OUTLET SIDE AND VALVE STEM LOCK SHIELD |
| Bonnet Type | INSIDE SPRING |
| Thread Direction | RIGHT-HAND ALL ENDS |
| Nominal Thread Size | 1.250 INCHES FIRST END IN |
| Nominal Thread Size | 0.500 INCHES SECOND END IN |
| Maximum Operating Temp | 225.0 FAHRENHEIT SINGLE RESPONSE DEGF |
| Bonnet Attachment Method | UNION |
| Media for Which Designed | WATER-OIL-GAS SINGLE RESPONSE |
| Material | BRONZE BODY |
| Material | STEEL COMP 304 SEAT |
| Material | PLASTIC POLYAMIDE NYLON FLOW CONTROL DEVICE |
| Thread Series Designator | NPT ALL ENDS |
| Opening Pressure Setting | 3000.0 POUNDS PER SQUARE INCH LBS |
| 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 |
|---|---|
| 6VR57-4-3 PRIMARY | Hydrasearch Company, Llc (USA) |
| Reference | Meaning |
|---|---|
| 157A 1-2X1 1-4I | C/1 Advisory reference — outside the item-of-supply concept U.S. Government activity |
| MV57-9 | C/1 Advisory reference — outside the item-of-supply concept Derbyshire Marine Products, Llc Dba Derbyshire Marine Products Llc |
| MV57-9 | 5/9 Secondary reference Derbyshire Machine & Tool Co |
| 157A 1/2X1 1/4 3000T6000PSI | 3/2 Design control — primary reference U.S. Government activity |
| 883117664 | D/9 Drawing number reference only U.S. Government activity |
NSN 4820-01-187-6822 is a Valve,safety Relief, manufactured by Hydrasearch Company, Llc, classified under FSC 4820, Valves, Nonpowered. Status: active.
NSN 4820-01-187-6822 has 1 manufacturer part number on file: 6VR57-4-3 (Hydrasearch Company, Llc).
Key specifications for 6VR57-4-3: Flow Control Device: DISK; Connection Style: PLAIN (PIPE) ALL ENDS; Connection Type: THREADED EXTERNAL PIPE ALL ENDS; Style Designator: ANGLE. 19 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.