The Valve,safety Relief, cataloged under National Stock Number 4820-01-273-3640, is classified within Federal Supply Class 4820 (Valves, Nonpowered) of the Valves group. Government technical data includes 18 specifications, cited from the U.S. Government catalog. 3 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog.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 | 4820-01-273-3640 |
| Item Name | Valve,safety Relief |
| FSC / FSG | 4820 / 48 — Valves, Nonpowered |
| Status | ACTIVE |
| Flow Control Device | DISK |
| Connection Style | PLAIN,OPTIONAL END(PIPE) SECOND END |
| Connection Style | PLAIN (PIPE) FIRST END |
| Connection Type | THREADED INTERNAL PIPE SECOND END |
| Connection Type | THREADED EXTERNAL PIPE FIRST END |
| Style Designator | ANGLE |
| Operating Pressure | 300.0 POUNDS PER SQUARE INCH (PSI) MAXIMUM SINGLE RESPONSE LBS |
| Thread Direction | RIGHT-HAND ALL ENDS |
| Nominal Thread Size | 0.750 INCHES ALL ENDS IN |
| Maximum Operating Temp | 406.0 FAHRENHEIT SINGLE RESPONSE DEGF |
| Disk Loading Method | SPRING |
| Media for Which Designed | STEAM SECOND RESPONSE |
| Media for Which Designed | AIR FIRST RESPONSE |
| Material | COPPER ALLOY BODY |
| Material | COPPER ALLOY FLOW CONTROL DEVICE |
| Thread Series Designator | NPT ALL ENDS |
| Opening Pressure Setting | 40.0 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 |
|---|---|
| 1542D 3/4IN 40PSI | 3/9 Design control — primary reference Ingersoll-Dresser Pump Co |
| 1542D 3/4IN 40PSI | 5/9 Secondary reference Ashcroft Inc Dba Heise |
| F-202 PART 844 | 5/9 Secondary reference Ingersoll-Dresser Pump Co |
NSN 4820-01-273-3640 is a Valve,safety Relief, classified under FSC 4820, Valves, Nonpowered. Status: active.
Key specifications for 4820-01-273-3640: Flow Control Device: DISK; Connection Style: PLAIN,OPTIONAL END(PIPE) SECOND END; Connection Style: PLAIN (PIPE) FIRST END; Connection Type: THREADED INTERNAL PIPE SECOND END. 18 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.