The Valve,safety Relief, cataloged under National Stock Number 4820-01-233-8959, 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18 specifications, cited from the U.S. Government catalog. 2 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 4820-01-233-8959 |
| Item Name | Valve,safety Relief |
| FSC / FSG | 4820 / 48 — Valves, Nonpowered |
| Status | ACTIVE |
| Flow Control Device | DISK |
| Connection Style | PLAIN,OPTIONAL END(PIPE) FIRST END |
| Connection Style | PLAIN (PIPE) SECOND END |
| Connection Type | THREADED INTERNAL PIPE FIRST END |
| Connection Type | THREADED EXTERNAL PIPE SECOND END |
| Style Designator | ANGLE |
| Operating Pressure | 250.0 POUNDS PER SQUARE INCH (PSI) MAXIMUM SINGLE RESPONSE LBS |
| Adjustable Pressure Range | +5.0 TO 250.0 POUNDS PER SQUARE INCH LBS |
| Thread Direction | RIGHT-HAND ALL ENDS |
| Nominal Thread Size | 1.250 INCHES FIRST END IN |
| Nominal Thread Size | 1.000 INCHES SECOND END IN |
| Maximum Operating Temp | 406.0 FAHRENHEIT SINGLE RESPONSE DEGF |
| Media for Which Designed | GAS, INERT SECOND RESPONSE |
| Media for Which Designed | STEAM THIRD RESPONSE |
| Media for Which Designed | AIR FIRST RESPONSE |
| Material | COPPER ALLOY OVERALL |
| Thread Series Designator | NPT ALL ENDS |
| 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 |
|---|---|
| 1543F-1IN5T250PSI | 3/9 Design control — primary reference Dresser, Inc. Dba Dresser Equipment Group Div Industrial Valve Operations, Dresse |
| 1543-1-F | 5/9 Secondary reference Dresser, Inc. Dba Dresser Equipment Group Div Industrial Valve Operations, Dresse |
NSN 4820-01-233-8959 is a Valve,safety Relief, classified under FSC 4820, Valves, Nonpowered. Status: active.
Key specifications for 4820-01-233-8959: Flow Control Device: DISK; Connection Style: PLAIN,OPTIONAL END(PIPE) FIRST END; Connection Style: PLAIN (PIPE) SECOND END; Connection Type: THREADED INTERNAL PIPE FIRST 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.