The Valve,safety Relief, cataloged under National Stock Number 4820-00-893-2107, 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25 specifications, cited from the U.S. Government catalog. 1 additional reference document (drawings, advisory and superseded references) is recorded in the U.S. Government catalog. Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 4820-00-893-2107 |
| Item Name | Valve,safety Relief |
| FSC / FSG | 4820 / 48 — Valves, Nonpowered |
| Status | ACTIVE |
| Flow Control Device | POPPET |
| Flange Shape | ROUND WITH HOLES FIRST END |
| Flange Shape | ROUND WITH HOLES SECOND END |
| Flange Face Design | RAISED STRAIGHT SECOND END |
| Flange Face Design | RAISED STRAIGHT FIRST END |
| Bolt Circle Nominal Diameter | 3.500 INCHES SECOND END IN |
| Bolt Circle Nominal Diameter | 2.625 INCHES FIRST END IN |
| Criticality Code Justification | ZZZY |
| Connection Type | FLANGE SECOND END |
| Connection Type | FLANGE FIRST END |
| Style Designator | ANGLE |
| Bolt Hole Nominal Diameter | 0.750 INCHES SECOND END IN |
| Bolt Hole Nominal Diameter | 0.625 INCHES FIRST END IN |
| Features Provided | VALVE STEM LOCK SHIELD |
| Nominal Outside Diameter | 3.750 INCHES FIRST END IN |
| Nominal Outside Diameter | 4.875 INCHES SECOND END IN |
| Disk Loading Method | SPRING |
| Bolt Hole Quantity | 4 SECOND END |
| Bolt Hole Quantity | 4 FIRST END |
| Material | NICKEL ALLOY FLOW CONTROL DEVICE |
| Material | NICKEL ALLOY BODY |
| Material | COBALT ALLOY BODY LINING |
| Opening Pressure Setting | 850.0 POUNDS PER SQUARE INCH LBS |
| Valve Operation Method | AUTOMATIC |
| Reference Number Differentiating Characteristics | SELECTED AND TESTED FOR NUCLEAR PROPULSION PLANT SYSTEMS |
| Acquisition Status | ACTIVE |
| DEMIL Code | DEMIL F — Mutilate — Cut |
| Hazard | No hazard code in the DLA record (HMIC N) |
| Criticality Code | C |
| Reference | Meaning |
|---|---|
| 5330F | 3/1 Design control — primary reference Atwood & Morrill Co., Inc. Dba Weir Valves and Controls Usa |
NSN 4820-00-893-2107 is a Valve,safety Relief, classified under FSC 4820, Valves, Nonpowered. Status: active.
Key specifications for 4820-00-893-2107: Flow Control Device: POPPET; Flange Shape: ROUND WITH HOLES FIRST END; Flange Shape: ROUND WITH HOLES SECOND END; Flange Face Design: RAISED STRAIGHT SECOND 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.
NSN 4820-00-893-2107 has DEMIL Code F. Demilitarization may be required before disposal or transfer to non-military entities.
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.