The Valve,safety Relief, cataloged under National Stock Number 4820-01-261-1681, is classified within Federal Supply Class 4820 (Valves, Nonpowered) of the Valves group. The manufacturer of record is Hunt Valve Company, Inc.. Government technical data includes 30 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through both NSN and commercial part number lookups. 3 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. 1 item shares a part number with this NSN in the catalog (possible match — not a government interchangeability claim). Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 4820-01-261-1681 |
| Primary Part Number | D49671 PART R10AE5F511-CM1 |
| Item Name | Valve,safety Relief |
| FSC / FSG | 4820 / 48 — Valves, Nonpowered |
| Manufacturer | Hunt Valve Company, Inc. |
| Status | ACTIVE |
| Flow Control Device | DISK |
| Flange Shape | ROUND WITH HOLES ALL ENDS |
| Flange Face Design | RAISED STRAIGHT ALL ENDS |
| Bolt Circle Nominal Diameter | 2.750 INCHES SECOND END IN |
| Bolt Circle Nominal Diameter | 3.125 INCHES FIRST END IN |
| Connection Type | FLANGE ALL ENDS |
| Style Designator | ANGLE FLANGED ENDS |
| Bolt Hole Nominal Diameter | 0.625 INCHES ALL ENDS IN |
| Operating Pressure | 1440.0 POUNDS PER SQUARE INCH (PSI) MAXIMUM SINGLE RESPONSE LBS |
| Valve Size | 0.750 INCHES IN |
| Adjustable Pressure Range | +48.0 TO 59.0 POUNDS PER SQUARE INCH LBS |
| Bonnet Type | INSIDE SPRING |
| Maximum Operating Temp | 400.0 FAHRENHEIT SINGLE RESPONSE DEGF |
| Second Connection Face to Centerline Distance | 3.672 INCHES IN |
| Nominal Outside Diameter | 3.875 INCHES SECOND END IN |
| Nominal Outside Diameter | 4.250 INCHES FIRST END IN |
| Disk Loading Method | SPRING |
| Bolt Hole Quantity | 4 ALL ENDS |
| Bonnet Attachment Method | THREADED |
| Media for Which Designed | WATER-OIL-GAS SINGLE RESPONSE |
| First Connection Face to Centerline Distance | 3.672 INCHES IN |
| Material | STEEL BODY |
| Material | STEEL COMP 303 STEM |
| Material | NICKEL ALLOY FLOW CONTROL DEVICE |
| Raised Face Nominal Diameter | 2.000 INCHES FIRST END IN |
| Raised Face Nominal Diameter | 1.688 INCHES SECOND END IN |
| Valve Operation Method | AUTOMATIC |
| Raised Face Nominal Height | 0.062 INCHES ALL ENDS IN |
| Nominal Thickness | 0.500 INCHES SECOND END IN |
| 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 |
|---|---|
| D49671 PART R10AE5F511-CM1 PRIMARY | Hunt Valve Company, Inc. (USA) |
| Reference | Meaning |
|---|---|
| D49671 PART R10AE5F511-CM1 | 3/9 Design control — primary reference Hunt Valve Company Inc Dba Union Flonetics |
| R10AE5F511-CM1 | C/1 Advisory reference — outside the item-of-supply concept Hunt Valve Company Inc Dba Union Flonetics |
| D49671 | D/9 Drawing number reference only Hunt Valve Company Inc Dba Union Flonetics |
NSN 4820-01-261-1681 is a Valve,safety Relief, manufactured by Hunt Valve Company, Inc., classified under FSC 4820, Valves, Nonpowered. Status: active.
NSN 4820-01-261-1681 has 1 manufacturer part number on file: D49671 PART R10AE5F511-CM1 (Hunt Valve Company, Inc.).
1 possible match (shared part number, not a government interchangeability claim): 4820-01-261-2463. Verify interchangeability with system specifications before substitution.
Key specifications for D49671 PART R10AE5F511-CM1: Flow Control Device: DISK; Flange Shape: ROUND WITH HOLES ALL ENDS; Flange Face Design: RAISED STRAIGHT ALL ENDS; Bolt Circle Nominal Diameter: 2.750 INCHES SECOND END IN. 30 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.