The Valve,safety Relief, cataloged under National Stock Number 4820-01-346-6202, is classified within Federal Supply Class 4820 (Valves, Nonpowered) of the Valves group. The manufacturer of record is Naval Sea Systems Command. Government technical data includes 16 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through both NSN and commercial part number lookups. 2 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog.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 | 4820-01-346-6202 |
| Primary Part Number | 6511599-2 |
| Item Name | Valve,safety Relief |
| FSC / FSG | 4820 / 48 — Valves, Nonpowered |
| Manufacturer | Naval Sea Systems Command |
| Status | ACTIVE |
| Flow Control Device | DISK |
| Connection Style | PLAIN (SCREW-IN CARTRIDGE) ALL ENDS |
| Connection Type | THREADED CARTRIDGE ALL ENDS |
| Style Designator | SCREW-IN CARTRIDGE |
| Thread Direction | RIGHT-HAND ALL ENDS |
| Nominal Thread Size | 0.250 INCHES ALL ENDS IN |
| Maximum Operating Temp | 250.0 FAHRENHEIT SINGLE RESPONSE DEGF |
| Media for Which Designed | AIR SECOND RESPONSE |
| Media for Which Designed | HYDROGEN THIRD RESPONSE |
| Media for Which Designed | ACETYLENE FIRST RESPONSE |
| Media for Which Designed | REFRIGERANT 12 FIFTH RESPONSE |
| Media for Which Designed | GAS, INERT FOURTH RESPONSE |
| Material | STEEL COMP 316 BODY |
| Thread Series Designator | NPT ALL ENDS |
| Opening Pressure Setting | 20.0 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 |
|---|---|
| 6511599-2 PRIMARY | Naval Sea Systems Command (USA) |
| Reference | Meaning |
|---|---|
| 559T1-2MP-20 | 5/2 Secondary reference U.S. Government activity |
| 6511599 | 7/1 Vendor item drawing reference Naval Sea Systems Command |
NSN 4820-01-346-6202 is a Valve,safety Relief, manufactured by Naval Sea Systems Command, classified under FSC 4820, Valves, Nonpowered. Status: active.
NSN 4820-01-346-6202 has 1 manufacturer part number on file: 6511599-2 (Naval Sea Systems Command).
Key specifications for 6511599-2: Flow Control Device: DISK; Connection Style: PLAIN (SCREW-IN CARTRIDGE) ALL ENDS; Connection Type: THREADED CARTRIDGE ALL ENDS; Style Designator: SCREW-IN CARTRIDGE. 16 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.