The Seat,valve, cataloged under National Stock Number 4820-00-306-4840, is classified within Federal Supply Class 4820 (Valves, Nonpowered) of the Valves group. Government technical data includes 10 specifications, cited from the U.S. Government catalog. 1 additional reference document (drawings, advisory and superseded references) is recorded in the U.S. Government catalog.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 | 4820-00-306-4840 |
| Item Name | Seat,valve |
| FSC / FSG | 4820 / 48 — Valves, Nonpowered |
| Status | ACTIVE |
| FSC Application Data | VALVE,SAFETY RELIEF,NONPOWERED |
| Seal Accommodation Type | RECESSED |
| Hardness Rating | 53.0 ROCKWELL C MINIMUM AND 62.0 ROCKWELL C MAXIMUM BODY |
| Hardness Rating | 53.0 ROCKWELL C MINIMUM AND 62.0 ROCKWELL C MAXIMUM FACE |
| Style Designator | PLAIN THREADED |
| Body Inside Diameter | 0.154 INCHES MINIMUM AND 0.158 INCHES MAXIMUM IN |
| Nominal Thread Size | 0.164 INCHES SINGLE THREADED PORTION IN |
| Thread Class | 2B SINGLE THREADED PORTION |
| Thread Series Designator | UNIFIED NATIONAL COARSE (UNC) SINGLE THREADED PORTION |
| Seating Surface Shape | FLAT |
| 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 |
|---|---|
| 1039 | 3/2 Design control — primary reference U.S. Government activity |
NSN 4820-00-306-4840 is a Seat,valve, classified under FSC 4820, Valves, Nonpowered. Status: active.
Key specifications for 4820-00-306-4840: Overall Height: 0.668 INCHES MINIMUM AND 0.678 INCHES MAXIMUM IN; FSC Application Data: VALVE,SAFETY RELIEF,NONPOWERED; Seal Accommodation Type: RECESSED; Hardness Rating: 53.0 ROCKWELL C MINIMUM AND 62.0 ROCKWELL C MAXIMUM BODY. 10 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 4820-00-306-4840 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.