The Valve,safety Relief, cataloged under National Stock Number 4820-00-446-3587, is classified within Federal Supply Class 4820 (Valves, Nonpowered) of the Valves group. The manufacturer of record is Hatch & Kirk, Inc.. Government technical data includes 21 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through both NSN and commercial part number lookups. 2 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 4820-00-446-3587 |
| Primary Part Number | 3305721 |
| Item Name | Valve,safety Relief |
| FSC / FSG | 4820 / 48 — Valves, Nonpowered |
| Manufacturer | Hatch & Kirk, Inc. |
| Status | ACTIVE |
| Flow Control Device | DISK |
| Flange Shape | ROUND WITH HOLES FIRST END |
| Flange Face Design | PLAIN FIRST END |
| Bolt Circle Nominal Diameter | 5.000 INCHES FIRST END IN |
| Connection Type | FLANGE FIRST END |
| Style Designator | ANGLE |
| Bolt Hole Nominal Diameter | 0.562 INCHES FIRST END IN |
| Operating Pressure | 100.0 POUNDS PER SQUARE INCH (PSI) MAXIMUM SINGLE RESPONSE LBS |
| Adjustable Pressure Range | +26.0 TO 75.0 POUNDS PER SQUARE INCH LBS |
| Bonnet Type | INSIDE SPRING |
| Maximum Operating Temp | 425.0 FAHRENHEIT SINGLE RESPONSE DEGF |
| Nominal Outside Diameter | 6.125 INCHES FIRST END IN |
| Disk Loading Method | SPRING |
| Bolt Hole Quantity | 6 FIRST END |
| Bonnet Attachment Method | THREADED |
| Material | COPPER ALLOY BODY |
| Material | COPPER ALLOY FLOW CONTROL DEVICE |
| Material | COPPER ALLOY STEM |
| Material | COPPER ALLOY SEAT |
| Valve Operation Method | AUTOMATIC |
| Nominal Thickness | 0.562 INCHES FIRST END IN |
| 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 |
|---|---|
| 3305721 PRIMARY | Hatch & Kirk, Inc. (USA) |
| Reference | Meaning |
|---|---|
| 3305721 | 5/9 Secondary reference General Motors Corp Electro-Motive Div |
| 81125S41-21502ALT1PC9 | 3/2 Design control — primary reference U.S. Government activity |
NSN 4820-00-446-3587 is a Valve,safety Relief, manufactured by Hatch & Kirk, Inc., classified under FSC 4820, Valves, Nonpowered. Status: active.
NSN 4820-00-446-3587 has 1 manufacturer part number on file: 3305721 (Hatch & Kirk, Inc.).
Key specifications for 3305721: Flow Control Device: DISK; Flange Shape: ROUND WITH HOLES FIRST END; Flange Face Design: PLAIN FIRST END; Bolt Circle Nominal Diameter: 5.000 INCHES FIRST END IN. 21 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.