The Valve,safety Relief, cataloged under National Stock Number 4820-01-004-5078, is classified within Federal Supply Class 4820 (Valves, Nonpowered) of the Valves group. The manufacturer of record is Swagelok Co. Government technical data includes 16 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through both NSN and commercial part number lookups. 3 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. 1 item shares a part number with this NSN in the catalog (possible match — not a government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 | 4820-01-004-5078 |
| Primary Part Number | B-4CPA2-3 |
| Item Name | Valve,safety Relief |
| FSC / FSG | 4820 / 48 — Valves, Nonpowered |
| Manufacturer | Swagelok Co |
| Status | ACTIVE |
| Flow Control Device | POPPET |
| Renewable Seat Ring Type | PRESSED-IN |
| Connection Style | PLAIN (PIPE) ALL ENDS |
| Connection Type | THREADED EXTERNAL PIPE ALL ENDS |
| Style Designator | STRAIGHT THRU |
| Operating Pressure | 2500.0 POUNDS PER SQUARE INCH (PSI) MAXIMUM SINGLE RESPONSE LBS |
| Adjustable Pressure Range | +3.0 TO 50.0 POUNDS PER SQUARE INCH LBS |
| Thread Direction | RIGHT-HAND ALL ENDS |
| Nominal Thread Size | 0.250 INCHES ALL ENDS IN |
| Disk Loading Method | SPRING |
| Media for Which Designed | WATER-OIL-GAS SINGLE RESPONSE |
| Material | COPPER ALLOY BODY |
| Material | COPPER ALLOY FLOW CONTROL DEVICE |
| Material | COPPER ALLOY SEAT |
| Thread Series Designator | NPT ALL ENDS |
| Valve Operation Method | AUTOMATIC |
| 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 |
|---|---|
| B-4CPA2-3 PRIMARY | Swagelok Co (USA) |
| Reference | Meaning |
|---|---|
| 4820PL2070557 | 6/9 Informative reference only Jednolity Indeks Materialowy - Uniform Material Index |
| B-4CPA2-3 | 5/9 Secondary reference Nupro Co |
| 19E3-101 | 5/2 Secondary reference U.S. Government activity |
NSN 4820-01-004-5078 is a Valve,safety Relief, manufactured by Swagelok Co, classified under FSC 4820, Valves, Nonpowered. Status: active.
NSN 4820-01-004-5078 has 1 manufacturer part number on file: B-4CPA2-3 (Swagelok Co).
1 possible match (shared part number, not a government interchangeability claim): 4820-01-416-0726. Verify interchangeability with system specifications before substitution.
Key specifications for B-4CPA2-3: Flow Control Device: POPPET; Renewable Seat Ring Type: PRESSED-IN; Connection Style: PLAIN (PIPE) ALL ENDS; Connection Type: THREADED EXTERNAL PIPE ALL ENDS. 16 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.