The Thread Piece,union, cataloged under National Stock Number 4730-00-554-9879, is classified within Federal Supply Class 4730 (Hose, Pipe, Tube, Lubrication, and Railing Fittings) of the Pipe, Tubing, Hose, and Fittings group. The manufacturer of record is Naval Group Site De Brest. Government technical data includes 12 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through both NSN and commercial part number lookups. 1 additional reference document (drawings, advisory and superseded references) is recorded in the U.S. Government catalog. 1 item shares a part number with this NSN in the catalog (possible match — not a government interchangeability claim). Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 4730-00-554-9879 |
| Primary Part Number | EPA21000-257 |
| Item Name | Thread Piece,union |
| FSC / FSG | 4730 / 47 — Hose, Pipe, Tube, Lubrication, and Railing Fittings |
| Manufacturer | Naval Group Site De Brest |
| Status | ACTIVE |
| Union End Thread Direction | RIGHT-HAND |
| Material Hardness Rating | 92.0 ROCKWELL B MINIMUM AND 98.0 ROCKWELL B MAXIMUM |
| End Connection Type | THREADED |
| Union End Thread Size | 1-3/16IN-12 IN |
| Seat Type | STRAIGHT FACE |
| Thread Direction | RIGHT-HAND |
| Thread Size | 1/4-18 |
| Screw Thread Series Designator | NPSM |
| Union End Screw Thread Series Designator | UN |
| Screw Thread Location | EXTERNAL |
| Material | STEEL COMP 4130 |
| Working Pressure and Service Type | 4000.0 POUNDS PER SQUARE INCH (PSI) NOMINAL WATER LBS |
| 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 |
|---|---|
| EPA21000-257 | Naval Group Site De Brest (FRA) |
| Reference | Meaning |
|---|---|
| A316215-1 | 3/2 Design control — primary reference U.S. Government activity |
NSN 4730-00-554-9879 is a Thread Piece,union, manufactured by Naval Group Site De Brest, classified under FSC 4730, Hose, Pipe, Tube, Lubrication, and Railing Fittings. Status: active.
NSN 4730-00-554-9879 has 1 manufacturer part number on file: EPA21000-257 (Naval Group Site De Brest).
1 possible match (shared part number, not a government interchangeability claim): 1720-00-602-0992. Verify interchangeability with system specifications before substitution.
Key specifications for EPA21000-257: Union End Thread Direction: RIGHT-HAND; Material Hardness Rating: 92.0 ROCKWELL B MINIMUM AND 98.0 ROCKWELL B MAXIMUM; End Connection Type: THREADED; Union End Thread Size: 1-3/16IN-12 IN. 12 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.