The Seat,valve, cataloged under National Stock Number 4820-01-254-2983, 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14 specifications, cited from the U.S. Government catalog. 1 additional reference document (drawings, advisory and superseded references) is recorded in the U.S. Government catalog. Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 4820-01-254-2983 |
| Item Name | Seat,valve |
| FSC / FSG | 4820 / 48 — Valves, Nonpowered |
| Status | ACTIVE |
| Flange Seat to Disk End Height | 0.080 INCHES NOMINAL IN |
| Flange Diameter | 0.486 INCHES NOMINAL IN |
| FSC Application Data | AIRCRAFT HYDRAULIC VACUUM DEICING SYSTEMS |
| Surface Treatment Document and Classification | MIL-S-5002 MIL SPEC SINGLE TREATMENT RESPONSE OVERALL |
| Body Outside Diameter | 0.486 INCHES NOMINAL IN |
| Hardness Rating | 56.0 ROCKWELL C MINIMUM AND 60.0 ROCKWELL C MAXIMUM OVERALL |
| Style Designator | PLAIN FLANGED |
| Material Document and Classification | QQ-S-763 FED SPEC SINGLE MATERIAL RESPONSE OVERALL |
| Body Inside Diameter | 0.200 INCHES NOMINAL IN |
| Surface Treatment | PHOSPHATE OVERALL |
| Under Flange Height | 0.230 INCHES NOMINAL IN |
| Material | STEEL COMP 440A OVERALL A |
| Seat Angle in Deg | 30.000 NOMINAL |
| Seating Surface Shape | ANGULAR |
| Acquisition Status | ACTIVE |
| DEMIL Code | DEMIL Q — CCL Item — Commerce Control List |
| Hazard | No hazard code in the DLA record (HMIC N) |
| Criticality Code | X |
| Reference | Meaning |
|---|---|
| T21486-1 | 3/2 Design control — primary reference U.S. Government activity |
NSN 4820-01-254-2983 is a Seat,valve, classified under FSC 4820, Valves, Nonpowered. Status: active.
Key specifications for 4820-01-254-2983: Flange Seat to Disk End Height: 0.080 INCHES NOMINAL IN; Flange Diameter: 0.486 INCHES NOMINAL IN; FSC Application Data: AIRCRAFT HYDRAULIC VACUUM DEICING SYSTEMS; Surface Treatment Document and Classification: MIL-S-5002 MIL SPEC SINGLE TREATMENT RESPONSE OVERALL. 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.
NSN 4820-01-254-2983 has DEMIL Code Q. 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.