The Valve,safety Relief, cataloged under National Stock Number 4820-01-188-1900, 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10 specifications, cited from the U.S. Government catalog. 4 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. 1 item shares a part number with this NSN in the catalog (possible match — not a government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 | 4820-01-188-1900 |
| Item Name | Valve,safety Relief |
| FSC / FSG | 4820 / 48 — Valves, Nonpowered |
| Status | ACTIVE |
| Flow Control Device | STEM |
| Connection Style | PLAIN (TUBE) ALL ENDS |
| Connection Type | THREADED EXTERNAL TUBE ALL ENDS |
| Operating Pressure | 3000.0 POUNDS PER SQUARE INCH (PSI) MAXIMUM SINGLE RESPONSE LBS |
| Thread Direction | RIGHT-HAND ALL ENDS |
| Nominal Thread Size | 0.875 INCHES ALL ENDS IN |
| Thread Class | 2A ALL ENDS A |
| Material | NICKEL ALLOY BODY |
| Material | ALUMINUM AND COPPER ALLOY STEM |
| Thread Series Designator | UNF ALL ENDS |
| Acquisition Status | ACTIVE |
| DEMIL Code | DEMIL A — No Demilitarization Required |
| Hazard | No hazard code in the DLA record (HMIC N) |
| Criticality Code | X |
| Reference | Meaning |
|---|---|
| SS845-2050985 | D/9 Drawing number reference only U.S. Government activity |
| 2640-602 | D/9 Drawing number reference only U.S. Government activity |
| SS845-2050985ASSYE | 3/2 Design control — primary reference U.S. Government activity |
| 2640-602ASSYE | 3/2 Design control — primary reference U.S. Government activity |
NSN 4820-01-188-1900 is a Valve,safety Relief, classified under FSC 4820, Valves, Nonpowered. Status: active.
1 possible match (shared part number, not a government interchangeability claim): 4820-01-200-8551. Verify interchangeability with system specifications before substitution.
Key specifications for 4820-01-188-1900: Flow Control Device: STEM; Connection Style: PLAIN (TUBE) ALL ENDS; Connection Type: THREADED EXTERNAL TUBE ALL ENDS; Operating Pressure: 3000.0 POUNDS PER SQUARE INCH (PSI) MAXIMUM SINGLE RESPONSE LBS. 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.
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.