The Valve,safety Relief, cataloged under National Stock Number 4820-01-057-6793, is classified within Federal Supply Class 4820 (Valves, Nonpowered) of the Valves group. The manufacturer of record is Naval Air Systems Command Managed Original Design Activity Not Material/parts Supplier. Government technical data includes 20 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through both NSN and commercial part number lookups. 3 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 4820-01-057-6793 |
| Primary Part Number | 639AS1366-2 |
| Item Name | Valve,safety Relief |
| FSC / FSG | 4820 / 48 — Valves, Nonpowered |
| Manufacturer | Naval Air Systems Command Managed Original Design Activity Not Material/parts Supplier |
| Status | ACTIVE |
| Flow Control Device | POPPET |
| Connection Style | PLAIN,OPTIONAL END(PIPE) ALL ENDS |
| Connection Type | THREADED INTERNAL PIPE ALL ENDS |
| Style Designator | STRAIGHT THRU NOTE: TO BE USED FOR VALVE BODIES OF SEPARABLE SECTIONS. |
| Material Document and Classification | ASTM A582,TYPE 303,COND A ASSN STD SINGLE MATERIAL RESPONSE BODY |
| Material Document and Classification | ASTM A582,TYPE 303,COND A ASSN STD SINGLE MATERIAL RESPONSE SEAT |
| Material Document and Classification | L-P-410 ASSN STD SINGLE MATERIAL RESPONSE FLOW CONTROL DEVICE |
| Thread Direction | RIGHT-HAND ALL ENDS |
| Nominal Thread Size | 0.250 INCHES ALL ENDS IN |
| Maximum Operating Temp | 250.0 FAHRENHEIT SINGLE RESPONSE DEGF |
| Disk Loading Method | SPRING |
| Surface Treatment | PASSIVATE LOCATION NOT OTHERWISE SPECIFIED |
| Media for Which Designed | WATER-OIL-GAS SINGLE RESPONSE |
| Material | STEEL COMP 303 SEAT |
| Material | PLASTIC POLYAMIDE NYLON FLOW CONTROL DEVICE |
| Material | STEEL COMP 303 BODY |
| Thread Series Designator | NPT ALL ENDS |
| Opening Pressure Setting | 5500.0 POUNDS PER SQUARE INCH LBS |
| Valve Discharge Flow Rate | 500.0 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 |
|---|---|
| 639AS1366-2 | Naval Air Systems Command Managed Original Design Activity Not Material/parts Supplier (USA) |
| Reference | Meaning |
|---|---|
| 639AS1366 | 7/1 Vendor item drawing reference Naval Air Systems Command Managed Original Design Activity Not Material/parts Supplier |
| 5349T-2PP-L-5500 | 5/9 Secondary reference U.S. Government activity |
| 5349T-2PP-L-5500-2 | 3/2 Design control — primary reference U.S. Government activity |
NSN 4820-01-057-6793 is a Valve,safety Relief, manufactured by Naval Air Systems Command Managed Original Design Activity Not Material/parts Supplier, classified under FSC 4820, Valves, Nonpowered. Status: active.
NSN 4820-01-057-6793 has 1 manufacturer part number on file: 639AS1366-2 (Naval Air Systems Command Managed Original Design Activity Not Material/parts Supplier).
Key specifications for 639AS1366-2: Flow Control Device: POPPET; Connection Style: PLAIN,OPTIONAL END(PIPE) ALL ENDS; Connection Type: THREADED INTERNAL PIPE ALL ENDS; Style Designator: STRAIGHT THRU NOTE: TO BE USED FOR VALVE BODIES OF SEPARABLE SECTIONS.. 20 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.