The Seat,valve, cataloged under National Stock Number 4820-01-055-4056, is classified within Federal Supply Class 4820 (Valves, Nonpowered) of the Valves group. Government technical data includes 8 specifications, cited from the U.S. Government catalog. 1 additional reference document (drawings, advisory and superseded references) is recorded in the U.S. Government catalog. 2 items share a part number with this NSN in the catalog (possible match — not a government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 | 4820-01-055-4056 |
| Item Name | Seat,valve |
| FSC / FSG | 4820 / 48 — Valves, Nonpowered |
| Status | ACTIVE |
| Flange Seat to Disk End Height | 0.050 INCHES MINIMUM AND 0.060 INCHES MAXIMUM IN |
| Body Outside Diameter | 0.618 INCHES MINIMUM AND 0.623 INCHES MAXIMUM IN |
| Style Designator | PLAIN FLANGED |
| Body Inside Diameter | 0.316 INCHES NOMINAL IN |
| Surface Treatment | ANODIZE OVERALL |
| Under Flange Height | 0.900 INCHES MINIMUM AND 0.910 INCHES MAXIMUM IN |
| Material | ALUMINUM ALLOY 6061 OVERALL |
| 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 |
|---|---|
| 203160 | 3/2 Design control — primary reference U.S. Government activity |
NSN 4820-01-055-4056 is a Seat,valve, classified under FSC 4820, Valves, Nonpowered. Status: active.
2 possible matches (shared part number, not a government interchangeability claim): 4320-01-187-2083, 5305-01-317-8523. Verify interchangeability with system specifications before substitution.
Key specifications for 4820-01-055-4056: Flange Seat to Disk End Height: 0.050 INCHES MINIMUM AND 0.060 INCHES MAXIMUM IN; Body Outside Diameter: 0.618 INCHES MINIMUM AND 0.623 INCHES MAXIMUM IN; Style Designator: PLAIN FLANGED; Body Inside Diameter: 0.316 INCHES NOMINAL IN. 8 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.