The Valve,safety Relief, cataloged under National Stock Number 4820-00-604-4656, is classified within Federal Supply Class 4820 (Valves, Nonpowered) of the Valves group. Government technical data includes 25 specifications, cited from the U.S. Government catalog. 3 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 4820-00-604-4656 |
| Item Name | Valve,safety Relief |
| FSC / FSG | 4820 / 48 — Valves, Nonpowered |
| Status | ACTIVE |
| Flow Control Device | POPPET |
| Furnished Items and Quantity | 1 DEFLECTOR CAP |
| Renewable Seat Ring Type | PRESSED-IN |
| Connection Style | PLAIN (TUBE) FIRST END |
| Connection Type | THREADED EXTERNAL TUBE FIRST END |
| Style Designator | STRAIGHT THRU W/BAFFLE |
| Nominal Outside Diameter Tube Accommodated | 0.250 INCHES FIRST END IN |
| Operating Pressure | 200.0 POUNDS PER SQUARE INCH (PSI) MAXIMUM SINGLE RESPONSE LBS |
| Thread Direction | RIGHT-HAND FIRST END |
| Nominal Thread Size | 0.438 INCHES FIRST END IN |
| Maximum Operating Temp | -40.0 FAHRENHEIT FIRST RESPONSE DEGF |
| Maximum Operating Temp | 250.0 FAHRENHEIT SECOND RESPONSE DEGF |
| Disk Loading Method | SPRING |
| Media for Which Designed | HELIUM FIFTH RESPONSE |
| Media for Which Designed | FUEL/OIL, HYDROCARBON FOURTH RESPONSE |
| Media for Which Designed | ALCOHOL, ETHYL SECOND RESPONSE |
| Media for Which Designed | AMMONIA, GASEOUS THIRD RESPONSE |
| Media for Which Designed | AIR FIRST RESPONSE |
| Thread Class | 3A FIRST END A |
| Material | ALUMINUM ALLOY SEAT |
| Material | ALUMINUM ALLOY BODY |
| Material | ALUMINUM ALLOY AND RUBBER BUTADIENE-ACRYLONITRILE CLASS NBR FLOW CONTROL DEVICE |
| Thread Series Designator | UNIFIED NATIONAL JOINT FINE (UNJF) FIRST END |
| Opening Pressure Setting | 50.0 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 |
| Reference | Meaning |
|---|---|
| D559A-4D-50 | 3/2 Design control — primary reference U.S. Government activity |
| 6153-30-50 | 5/9 Secondary reference Air Dry Co of America, Llc |
| 6153-30-50 | 3/2 Design control — primary reference U.S. Government activity |
NSN 4820-00-604-4656 is a Valve,safety Relief, classified under FSC 4820, Valves, Nonpowered. Status: active.
Key specifications for 4820-00-604-4656: Flow Control Device: POPPET; Furnished Items and Quantity: 1 DEFLECTOR CAP; Renewable Seat Ring Type: PRESSED-IN; Connection Style: PLAIN (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.