The Seat,valve, cataloged under National Stock Number 4820-01-270-9644, is classified within Federal Supply Class 4820 (Valves, Nonpowered) of the Valves group. The manufacturer of record is Norgren C a Co. Government technical data includes 13 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. 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 | 4820-01-270-9644 |
| Primary Part Number | 999-01 |
| Item Name | Seat,valve |
| FSC / FSG | 4820 / 48 — Valves, Nonpowered |
| Manufacturer | Norgren C a Co |
| Status | ACTIVE |
| Flange Seat to Disk End Height | 0.154 INCHES NOMINAL IN |
| Flange Diameter | 0.625 INCHES NOMINAL IN |
| Thread Length | 0.212 INCHES NOMINAL SINGLE THREADED PORTION IN |
| Style Designator | THREADED FLANGED |
| Body Inside Diameter | 0.192 INCHES NOMINAL IN |
| Nominal Thread Size | 0.625 INCHES SINGLE THREADED PORTION IN |
| Surface Treatment | CHROMIUM OVERALL |
| Under Flange Height | 0.375 INCHES NOMINAL IN |
| Thread Class | 3A SINGLE THREADED PORTION A |
| Thread Quantity Per Inch | 28 SINGLE THREADED PORTION |
| Material | ALUMINUM OVERALL |
| 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 |
| Part Number | Manufacturer |
|---|---|
| 999-01 PRIMARY | Norgren C a Co (USA) |
NSN 4820-01-270-9644 is a Seat,valve, manufactured by Norgren C a Co, classified under FSC 4820, Valves, Nonpowered. Status: active.
NSN 4820-01-270-9644 has 1 manufacturer part number on file: 999-01 (Norgren C a Co).
2 possible matches (shared part number, not a government interchangeability claim): 4940-01-594-5649, 8415-01-647-6009. Verify interchangeability with system specifications before substitution.
Key specifications for 999-01: Flange Seat to Disk End Height: 0.154 INCHES NOMINAL IN; Flange Diameter: 0.625 INCHES NOMINAL IN; Thread Length: 0.212 INCHES NOMINAL SINGLE THREADED PORTION IN; Style Designator: THREADED FLANGED. 13 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.