The Valve,safety Relief, cataloged under National Stock Number 4820-01-420-8658, is classified within Federal Supply Class 4820 (Valves, Nonpowered) of the Valves group. Government technical data includes 17 specifications, cited from the U.S. Government catalog. 3 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog.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 | 4820-01-420-8658 |
| Item Name | Valve,safety Relief |
| FSC / FSG | 4820 / 48 — Valves, Nonpowered |
| Status | ACTIVE |
| Nominal Pipe Size Accommodated | 0.375 INCHES SECOND END IN |
| Nominal Pipe Size Accommodated | 0.500 INCHES FIRST END IN |
| Connection Style | SOCKET ALL ENDS |
| Connection Type | UNTHREADED INTERNAL PIPE ALL ENDS |
| Style Designator | ANGLE |
| Material Document and Classification | ASTM A564, ALLOY S17400 ASSN STD SINGLE MATERIAL RESPONSE FLOW CONTROL DEVICE |
| Material Document and Classification | ASTM B150, ALLOY C63200 ASSN STD SINGLE MATERIAL RESPONSE BODY |
| Material Document and Classification | ASTM B21, ALLOY C464 ASSN STD SINGLE MATERIAL RESPONSE STEM |
| Material Document and Classification | QQ-S-763, CLASS 316 SS FED SPEC SINGLE MATERIAL RESPONSE SEAT |
| Operating Pressure | 5900.0 POUNDS PER SQUARE INCH (PSI) MAXIMUM SINGLE RESPONSE LBS |
| Adjustable Pressure Range | +3000.0 TO 6875.0 POUNDS PER SQUARE INCH LBS |
| Disk Loading Method | SPRING |
| Material | STEEL COMP 316 SEAT |
| Material | STEEL COMP 630 FLOW CONTROL DEVICE |
| Material | COPPER ALLOY 464 STEM |
| Material | COPPER ALLOY 632 BODY |
| 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 |
|---|---|
| PLC-11668 | D/9 Drawing number reference only U.S. Government activity |
| PLC-11668 CDA-11803 | 3/2 Design control — primary reference U.S. Government activity |
| PLC-11668CP CDA | C/1 Advisory reference — outside the item-of-supply concept Naval Inventory Control Point Mechanicsburg |
NSN 4820-01-420-8658 is a Valve,safety Relief, classified under FSC 4820, Valves, Nonpowered. Status: active.
Key specifications for 4820-01-420-8658: Nominal Pipe Size Accommodated: 0.375 INCHES SECOND END IN; Nominal Pipe Size Accommodated: 0.500 INCHES FIRST END IN; Connection Style: SOCKET ALL ENDS; Connection Type: UNTHREADED INTERNAL PIPE ALL ENDS. 17 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.