The Valve,safety Relief, cataloged under National Stock Number 4820-01-439-9033, is classified within Federal Supply Class 4820 (Valves, Nonpowered) of the Valves group. The manufacturer of record is L3 Technologies, Inc. Div L3 Keo. Government technical data includes 22 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through both NSN and commercial part number lookups. 1 additional reference document (drawings, advisory and superseded references) is recorded in the U.S. Government catalog.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 | 4820-01-439-9033 |
| Primary Part Number | 918531 |
| Item Name | Valve,safety Relief |
| FSC / FSG | 4820 / 48 — Valves, Nonpowered |
| Manufacturer | L3 Technologies, Inc. Div L3 Keo |
| Status | ACTIVE |
| Flow Control Device | POPPET |
| Furnished Items and Quantity | 1 DEFLECTOR CAP |
| Connection Style | FLARED (TUBE) FIRST END |
| Minimum Operating Temp | -100.0 FAHRENHEIT DEGF |
| Connection Type | THREADED EXTERNAL TUBE FIRST END |
| Style Designator | STRAIGHT THRU W/BAFFLE |
| Operating Pressure | 200.0 POUNDS PER SQUARE INCH (PSI) MAXIMUM SINGLE RESPONSE LBS |
| Bonnet Type | INSIDE SPRING |
| Thread Direction | RIGHT-HAND FIRST END |
| Nominal Thread Size | 0.438 INCHES FIRST END IN |
| Seat Angle | 37.0 DEGREES FIRST END |
| Maximum Operating Temp | 400.0 FAHRENHEIT SINGLE RESPONSE DEGF |
| Disk Loading Method | SPRING |
| Bonnet Attachment Method | INTEGRAL |
| Media for Which Designed | WATER-OIL-GAS SINGLE RESPONSE |
| Thread Class | 3A FIRST END A |
| Material | STEEL COMP 303 FLOW CONTROL DEVICE |
| Material | STEEL COMP 303 SEAT |
| Material | STEEL COMP 303 BODY |
| Thread Series Designator | UNIFIED NATIONAL JOINT FINE (UNJF) FIRST END |
| Opening Pressure Setting | 10.0 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 |
| Part Number | Manufacturer |
|---|---|
| 918531 | L3 Technologies, Inc. Div L3 Keo (USA) |
| Reference | Meaning |
|---|---|
| D520T4D10 | 3/2 Design control — primary reference U.S. Government activity |
NSN 4820-01-439-9033 is a Valve,safety Relief, manufactured by L3 Technologies, Inc. Div L3 Keo, classified under FSC 4820, Valves, Nonpowered. Status: active.
NSN 4820-01-439-9033 has 1 manufacturer part number on file: 918531 (L3 Technologies, Inc. Div L3 Keo).
Key specifications for 918531: Flow Control Device: POPPET; Furnished Items and Quantity: 1 DEFLECTOR CAP; Connection Style: FLARED (TUBE) FIRST END; Minimum Operating Temp: -100.0 FAHRENHEIT DEGF. 22 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.