The Seat,valve, cataloged under National Stock Number 4820-01-157-5578, is classified within Federal Supply Class 4820 (Valves, Nonpowered) of the Valves group. The manufacturer of record is Naval Sea Systems Command. Government technical data includes 12 specifications, cited from the U.S. Government catalog. The record lists 1 manufacturer part number for this item, enabling identification through both NSN and commercial part number lookups. 1 additional reference document (drawings, advisory and superseded references) is recorded in the U.S. Government catalog. Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 4820-01-157-5578 |
| Primary Part Number | 803-4384536-1XXX-46 |
| Item Name | Seat,valve |
| FSC / FSG | 4820 / 48 — Valves, Nonpowered |
| Manufacturer | Naval Sea Systems Command |
| Status | ACTIVE |
| Flange Seat to Disk End Height | 0.091 INCHES NOMINAL IN |
| Flange Diameter | 0.719 INCHES NOMINAL IN |
| Thread Length | 0.234 INCHES NOMINAL SINGLE THREADED PORTION IN |
| Style Designator | THREADED FLANGED |
| Body Inside Diameter | 0.250 INCHES NOMINAL IN |
| Nominal Thread Size | 0.625 INCHES SINGLE THREADED PORTION IN |
| Under Flange Height | 0.315 INCHES NOMINAL IN |
| Thread Class | 3A SINGLE THREADED PORTION A |
| Material | NICKEL ALLOY OVERALL |
| Seat Angle in Deg | 15.500 NOMINAL |
| Thread Series Designator | UNEF SINGLE THREADED PORTION |
| Seating Surface Shape | ANGULAR |
| Acquisition Status | ACTIVE |
| DEMIL Code | DEMIL A — No Demilitarization Required |
| Hazard | No hazard code in the DLA record (HMIC N) |
| Criticality Code | X |
| Part Number | Manufacturer |
|---|---|
| 803-4384536-1XXX-46 PRIMARY | Naval Sea Systems Command (USA) |
| Reference | Meaning |
|---|---|
| 803-4384536-1XXX-46 | 3/2 Design control — primary reference U.S. Government activity |
NSN 4820-01-157-5578 is a Seat,valve, manufactured by Naval Sea Systems Command, classified under FSC 4820, Valves, Nonpowered. Status: active.
NSN 4820-01-157-5578 has 1 manufacturer part number on file: 803-4384536-1XXX-46 (Naval Sea Systems Command).
Key specifications for 803-4384536-1XXX-46: Flange Seat to Disk End Height: 0.091 INCHES NOMINAL IN; Flange Diameter: 0.719 INCHES NOMINAL IN; Thread Length: 0.234 INCHES NOMINAL SINGLE THREADED PORTION IN; Style Designator: THREADED FLANGED. 12 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.