The Valve,safety Relief, cataloged under National Stock Number 4820-01-189-8525, is classified within Federal Supply Class 4820 (Valves, Nonpowered) of the Valves group. Government technical data includes 28 specifications, cited from the U.S. Government catalog. 2 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 4820-01-189-8525 |
| Item Name | Valve,safety Relief |
| FSC / FSG | 4820 / 48 — Valves, Nonpowered |
| Status | ACTIVE |
| Flow Control Device | POPPET |
| Furnished Items and Quantity | 1 DEFLECTOR CAP |
| Surface Treatment Document and Classification | MIL-A-8625A MIL SPEC SINGLE TREATMENT RESPONSE LOCATION NOT OTHERWISE SPECIFIED A |
| Connection Style | PLAIN (TUBE) ALL ENDS |
| Connection Type | THREADED EXTERNAL TUBE ALL ENDS |
| Style Designator | STRAIGHT THRU W/BAFFLE |
| Material Document and Classification | QQ-A-225/6 FED SPEC SINGLE MATERIAL RESPONSE BODY |
| Operating Pressure | 200.0 POUNDS PER SQUARE INCH (PSI) MAXIMUM SINGLE RESPONSE LBS |
| Bonnet Type | INSIDE SPRING |
| Thread Direction | RIGHT-HAND ALL ENDS |
| Nominal Thread Size | 0.438 INCHES ALL ENDS IN |
| Maximum Operating Temp | 400.0 FAHRENHEIT SECOND RESPONSE DEGF |
| Maximum Operating Temp | -100.0 FAHRENHEIT FIRST RESPONSE DEGF |
| Disk Loading Method | SPRING |
| Surface Treatment | ANODIZE LOCATION NOT OTHERWISE SPECIFIED |
| Bonnet Attachment Method | INTEGRAL |
| Media for Which Designed | NITROGEN, GASEOUS FIFTH RESPONSE |
| Media for Which Designed | HYDROGEN FOURTH RESPONSE |
| Media for Which Designed | HELIUM THIRD RESPONSE |
| Media for Which Designed | CARBON DIOXIDE SECOND RESPONSE |
| Media for Which Designed | AIR FIRST RESPONSE |
| Thread Class | 3A ALL ENDS A |
| Thread Quantity Per Inch | 20 ALL ENDS |
| Material | ALUMINUM ALLOY 2024 BODY |
| Material | SILICON SEAT |
| Thread Series Designator | UNIFIED NATIONAL JOINT FINE (UNJF) ALL ENDS |
| Opening Pressure Setting | 130.0 POUNDS PER SQUARE INCH LBS |
| 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 |
| Reference | Meaning |
|---|---|
| D524A-4D-130 | 5/9 Secondary reference U.S. Government activity |
| D520A-4D-130 | 3/2 Design control — primary reference U.S. Government activity |
NSN 4820-01-189-8525 is a Valve,safety Relief, classified under FSC 4820, Valves, Nonpowered. Status: active.
Key specifications for 4820-01-189-8525: Flow Control Device: POPPET; Furnished Items and Quantity: 1 DEFLECTOR CAP; Surface Treatment Document and Classification: MIL-A-8625A MIL SPEC SINGLE TREATMENT RESPONSE LOCATION NOT OTHERWISE SPECIFIED A; Connection Style: PLAIN (TUBE) ALL ENDS. 28 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.