The Valve,safety Relief, cataloged under National Stock Number 4820-00-203-8030, is classified within Federal Supply Class 4820 (Valves, Nonpowered) of the Valves group. Government technical data includes 29 specifications, cited from the U.S. Government catalog. 1 additional reference document (drawings, advisory and superseded references) is recorded in the U.S. Government catalog. 1 item shares a part number with this NSN in the catalog (possible match — not a government interchangeability claim). Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 4820-00-203-8030 |
| Item Name | Valve,safety Relief |
| FSC / FSG | 4820 / 48 — Valves, Nonpowered |
| Status | ACTIVE |
| Flow Control Device | POPPET |
| Flange Shape | ROUND WITH HOLES SECOND END |
| Renewable Seat Ring Type | THREADED |
| Nominal Pipe Size Accommodated | 1.500 INCHES FIRST END IN |
| Flange Face Design | PLAIN SECOND END |
| Connection Style | PLAIN,OPTIONAL END(PIPE) FIRST END |
| Bolt Circle Nominal Diameter | 3.375 INCHES SECOND END IN |
| Connection Type | FLANGE SECOND END |
| Connection Type | THREADED INTERNAL PIPE FIRST END |
| Style Designator | ANGLE FLANGED ENDS |
| Bolt Hole Nominal Diameter | 0.562 INCHES SECOND END IN |
| Operating Pressure | 100.0 POUNDS PER SQUARE INCH (PSI) MAXIMUM SINGLE RESPONSE LBS |
| Adjustable Pressure Range | +7.0 TO 25.0 POUNDS PER SQUARE INCH LBS |
| Features Provided | VALVE STEM LOCK SHIELD |
| Bonnet Type | EXPOSED SPRING |
| Thread Direction | RIGHT-HAND FIRST END |
| Nominal Thread Size | 1.500 INCHES FIRST END IN |
| Maximum Operating Temp | 425.0 FAHRENHEIT SINGLE RESPONSE DEGF |
| Second Connection Face to Centerline Distance | 2.188 INCHES IN |
| Nominal Outside Diameter | 4.500 INCHES SECOND END IN |
| Disk Loading Method | SPRING |
| Bolt Hole Quantity | 4 SECOND END |
| Bonnet Attachment Method | THREADED |
| Media for Which Designed | STEAM SINGLE RESPONSE |
| First Connection Face to Centerline Distance | 3.062 INCHES IN |
| Thread Quantity Per Inch | 11-1/2 FIRST END |
| Material | COPPER ALLOY BODY |
| Material | NICKEL ALLOY STEM |
| Material | NICKEL ALLOY FLOW CONTROL DEVICE |
| 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 |
|---|---|
| D4729 | 3/9 Design control — primary reference Lunkenheimer Co |
NSN 4820-00-203-8030 is a Valve,safety Relief, classified under FSC 4820, Valves, Nonpowered. Status: active.
1 possible match (shared part number, not a government interchangeability claim): 7025-01-702-0950. Verify interchangeability with system specifications before substitution.
Key specifications for 4820-00-203-8030: Flow Control Device: POPPET; Flange Shape: ROUND WITH HOLES SECOND END; Renewable Seat Ring Type: THREADED; Nominal Pipe Size Accommodated: 1.500 INCHES FIRST END IN. 29 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.