The Valve,safety Relief, cataloged under National Stock Number 4820-00-142-1020, is classified within Federal Supply Class 4820 (Valves, Nonpowered) of the Valves group. The manufacturer of record is Ashcroft Inc Dba Heise. Government technical data includes 28 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through both NSN and commercial part number lookups. 1 additional reference document (drawings, advisory and superseded references) is recorded in the U.S. Government catalog.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 | 4820-00-142-1020 |
| Primary Part Number | R-6134-AL |
| Item Name | Valve,safety Relief |
| FSC / FSG | 4820 / 48 — Valves, Nonpowered |
| Manufacturer | Ashcroft Inc Dba Heise |
| Status | ACTIVE |
| Flow Control Device | DISK |
| Flange Shape | ROUND WITH HOLES FIRST END |
| Flange Shape | ROUND WITH HOLES SECOND END |
| Flange Face Design | RAISED STRAIGHT FIRST END |
| Flange Face Design | PLAIN SECOND END |
| Bolt Circle Nominal Diameter | 5.875 INCHES FIRST END IN |
| Bolt Circle Nominal Diameter | 7.125 INCHES SECOND END IN |
| Style Designator | ANGLE FLANGED ENDS |
| Bolt Hole Nominal Diameter | 0.812 INCHES SECOND END IN |
| Bolt Hole Nominal Diameter | 0.812 INCHES FIRST END IN |
| Valve Size | 2.500 INCHES IN |
| Features Provided | VALVE STEM LOCK SHIELD |
| Bonnet Type | EXPOSED SPRING |
| Second Connection Face to Centerline Distance | 5.312 INCHES IN |
| Nominal Outside Diameter | 7.500 INCHES FIRST END IN |
| Nominal Outside Diameter | 8.688 INCHES SECOND END IN |
| Disk Loading Method | SPRING |
| Bolt Hole Quantity | 9 SECOND END |
| Bolt Hole Quantity | 8 FIRST END |
| Bonnet Attachment Method | BOLTED |
| First Connection Face to Centerline Distance | 6.000 INCHES IN |
| Raised Face Nominal Diameter | 4.125 INCHES FIRST END IN |
| Opening Pressure Setting | 630.0 POUNDS PER SQUARE INCH LBS |
| Valve Discharge Flow Rate | 49500.0 POUNDS PER HOUR LBS |
| Valve Operation Method | AUTOMATIC OR MANUAL |
| Raised Face Nominal Height | 0.250 INCHES FIRST END IN |
| Nominal Thickness | 0.750 INCHES SECOND END IN |
| Nominal Thickness | 1.125 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 |
|---|---|
| R-6134-AL | Ashcroft Inc Dba Heise (USA) |
| Reference | Meaning |
|---|---|
| R6134AL | 3/9 Design control — primary reference Dresser, Inc. Dba Dresser Equipment Group Div Industrial Valve Operations, Dresse |
NSN 4820-00-142-1020 is a Valve,safety Relief, manufactured by Ashcroft Inc Dba Heise, classified under FSC 4820, Valves, Nonpowered. Status: active.
NSN 4820-00-142-1020 has 1 manufacturer part number on file: R-6134-AL (Ashcroft Inc Dba Heise).
Key specifications for R-6134-AL: Flow Control Device: DISK; Flange Shape: ROUND WITH HOLES FIRST END; Flange Shape: ROUND WITH HOLES SECOND END; Flange Face Design: RAISED STRAIGHT FIRST END. 28 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.