The Valve,safety Relief, cataloged under National Stock Number 4820-01-138-8527, is classified within Federal Supply Class 4820 (Valves, Nonpowered) of the Valves group. Government technical data includes 13 specifications, cited from the U.S. Government catalog. 3 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 4820-01-138-8527 |
| Item Name | Valve,safety Relief |
| FSC / FSG | 4820 / 48 — Valves, Nonpowered |
| Status | ACTIVE |
| Flow Control Device | POPPET |
| Connection Style | PLAIN (PIPE) ALL ENDS |
| Minimum Operating Temp | -40.0 FAHRENHEIT DEGF |
| Connection Type | THREADED EXTERNAL PIPE ALL ENDS |
| Style Designator | STRAIGHT THRU |
| Thread Direction | RIGHT-HAND ALL ENDS |
| Nominal Thread Size | 0.125 INCHES ALL ENDS IN |
| Maximum Operating Temp | 250.0 FAHRENHEIT SINGLE RESPONSE DEGF |
| Disk Loading Method | SPRING |
| Material | COPPER ALLOY BODY |
| Thread Series Designator | NPT ALL ENDS |
| Opening Pressure Setting | 2.0 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 |
|---|---|
| 559B-1M-2 | 3/2 Design control — primary reference U.S. Government activity |
| 592-4759200 FIND 17 | 5/2 Secondary reference U.S. Government activity |
| 592-4759220 | 1/2 Source control — Government-approved source U.S. Government activity |
NSN 4820-01-138-8527 is a Valve,safety Relief, classified under FSC 4820, Valves, Nonpowered. Status: active.
Key specifications for 4820-01-138-8527: Flow Control Device: POPPET; Connection Style: PLAIN (PIPE) ALL ENDS; Minimum Operating Temp: -40.0 FAHRENHEIT DEGF; Connection Type: THREADED EXTERNAL PIPE ALL ENDS. 13 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.