The Seat,valve, cataloged under National Stock Number 4820-01-442-0424, is classified within Federal Supply Class 4820 (Valves, Nonpowered) of the Valves group. Government technical data includes 14 specifications, cited from the U.S. Government catalog. 6 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. 3 items share a part number with this NSN in the catalog (possible match — not a government interchangeability claim). Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 4820-01-442-0424 |
| Item Name | Seat,valve |
| FSC / FSG | 4820 / 48 — Valves, Nonpowered |
| Status | ACTIVE |
| Flange Seat to Disk End Height | 0.600 INCHES NOMINAL IN |
| Flange Diameter | 5.750 INCHES NOMINAL IN |
| Body Outside Diameter | 5.360 INCHES NOMINAL IN |
| Thread Length | 0.650 INCHES NOMINAL SINGLE THREADED PORTION IN |
| Hardness Rating | 115.0 ROCKWELL R NOMINAL SEAT |
| Style Designator | PLAIN FLANGED |
| Body Inside Diameter | 4.625 INCHES NOMINAL IN |
| Nominal Thread Size | 5.500 INCHES SINGLE THREADED PORTION IN |
| Under Flange Height | 0.775 INCHES NOMINAL IN |
| Thread Class | 3A SINGLE THREADED PORTION A |
| Thread Quantity Per Inch | 12 SINGLE THREADED PORTION |
| Material | PLASTIC POLYTETRAFLUOROETHYLENE SEAT |
| Thread Series Designator | UN SINGLE THREADED PORTION |
| Seating Surface Shape | FLAT |
| 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 |
|---|---|
| 218020208 | 3/9 Design control — primary reference Naval Sea Systems Command |
| 2643-1002-63 | D/9 Drawing number reference only U.S. Government activity |
| 801-6556655 FIND A5 | 5/9 Secondary reference Naval Sea Systems Command |
| 2643-1002-63 FN A5 | 5/9 Secondary reference U.S. Government activity |
| 801-6556655-A5 | 5/9 Secondary reference Naval Sea Systems Command |
| 6556655 | D/9 Drawing number reference only Naval Sea Systems Command |
NSN 4820-01-442-0424 is a Seat,valve, classified under FSC 4820, Valves, Nonpowered. Status: active.
3 possible matches (shared part number, not a government interchangeability claim): 4820-01-442-0439, 4820-01-442-0749, 4820-01-442-0793. Verify interchangeability with system specifications before substitution.
Key specifications for 4820-01-442-0424: Flange Seat to Disk End Height: 0.600 INCHES NOMINAL IN; Flange Diameter: 5.750 INCHES NOMINAL IN; Body Outside Diameter: 5.360 INCHES NOMINAL IN; Thread Length: 0.650 INCHES NOMINAL SINGLE THREADED PORTION IN. 14 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.