The Valve,safety Relief, cataloged under National Stock Number 4820-01-299-4011, is classified within Federal Supply Class 4820 (Valves, Nonpowered) of the Valves group. The manufacturer of record is Curtiss-Wright Flow Control Corporation Dba Farris Engineering Div Curtiss-Wright Valves Division- Farris. Government technical data includes 20 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through both NSN and commercial part number lookups. 1 additional reference document (drawings, advisory and superseded references) is recorded in the U.S. Government catalog. Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 4820-01-299-4011 |
| Primary Part Number | 1856M-OL 1/2IN |
| Item Name | Valve,safety Relief |
| FSC / FSG | 4820 / 48 — Valves, Nonpowered |
| Manufacturer | Curtiss-Wright Flow Control Corporation Dba Farris Engineering Div Curtiss-Wright Valves Division- Farris |
| Status | ACTIVE |
| Flow Control Device | DISK |
| Connection Style | PLAIN,OPTIONAL END(PIPE) SECOND END |
| Connection Style | PLAIN (PIPE) FIRST END |
| Connection Type | THREADED INTERNAL PIPE SECOND END |
| Connection Type | THREADED EXTERNAL PIPE FIRST END |
| Style Designator | ANGLE |
| Bonnet Type | INSIDE SCREW |
| Thread Direction | RIGHT-HAND ALL ENDS |
| Nominal Thread Size | 0.750 INCHES SECOND END IN |
| Nominal Thread Size | 0.500 INCHES FIRST END IN |
| Maximum Operating Temp | 450.0 FAHRENHEIT SINGLE RESPONSE DEGF |
| Disk Loading Method | SPRING |
| Bonnet Attachment Method | THREADED |
| Media for Which Designed | STEAM SINGLE RESPONSE |
| Material | COPPER ALLOY 360 FLOW CONTROL DEVICE |
| Material | COPPER ALLOY 360 STEM |
| Material | COPPER ALLOY 360 OR COPPER ALLOY 922 BODY |
| Thread Series Designator | NPT ALL ENDS |
| Opening Pressure Setting | 300.0 POUNDS PER SQUARE INCH LBS |
| Valve Operation Method | AUTOMATIC OR MANUAL |
| 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 |
|---|---|
| 1856M-OL 1/2IN PRIMARY | Curtiss-Wright Flow Control Corporation Dba Farris Engineering Div Curtiss-Wright Valves Division- Farris (USA) |
| Reference | Meaning |
|---|---|
| 18252-F REV A | C/1 Advisory reference — outside the item-of-supply concept Curtiss-Wright Flow Control Corporation Dba Farris Engineering Div Curtiss-Wright Valves Division- Farris |
NSN 4820-01-299-4011 is a Valve,safety Relief, manufactured by Curtiss-Wright Flow Control Corporation Dba Farris Engineering Div Curtiss-Wright Valves Division- Farris, classified under FSC 4820, Valves, Nonpowered. Status: active.
NSN 4820-01-299-4011 has 1 manufacturer part number on file: 1856M-OL 1/2IN (Curtiss-Wright Flow Control Corporation Dba Farris Engineering Div Curtiss-Wright Valves Division- Farris).
Key specifications for 1856M-OL 1/2IN: Flow Control Device: DISK; Connection Style: PLAIN,OPTIONAL END(PIPE) SECOND END; Connection Style: PLAIN (PIPE) FIRST END; Connection Type: THREADED INTERNAL PIPE SECOND END. 20 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.