The Valve,safety Relief, cataloged under National Stock Number 4820-01-451-2691, is classified within Federal Supply Class 4820 (Valves, Nonpowered) of the Valves group. Government technical data includes 25 specifications, cited from the U.S. Government catalog. 3 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 4820-01-451-2691 |
| Item Name | Valve,safety Relief |
| FSC / FSG | 4820 / 48 — Valves, Nonpowered |
| Status | ACTIVE |
| Flow Control Device | DISK |
| Furnished Items and Quantity | 1 LEVER |
| Connection Style | PLAIN,OPTIONAL END(PIPE) SECOND END |
| Connection Style | PLAIN (PIPE) FIRST END |
| Minimum Operating Temp | -20.0 FAHRENHEIT DEGF |
| Connection Type | THREADED INTERNAL PIPE SECOND END |
| Connection Type | THREADED EXTERNAL PIPE FIRST END |
| Style Designator | ANGLE |
| Material Document and Classification | ASTM A479 ASSN STD SINGLE MATERIAL RESPONSE FLOW CONTROL DEVICE |
| Material Document and Classification | ASTM A479 ASSN STD SINGLE MATERIAL RESPONSE BODY |
| Material Document and Classification | ASTM A276 COND T ASSN STD SINGLE MATERIAL RESPONSE STEM |
| Operating Pressure | 2000.0 POUNDS PER SQUARE INCH (PSI) MAXIMUM SINGLE RESPONSE LBS |
| Thread Direction | RIGHT-HAND ALL ENDS |
| Nominal Thread Size | 1.000 INCHES SECOND END IN |
| Nominal Thread Size | 0.750 INCHES FIRST END IN |
| Maximum Operating Temp | 400.0 FAHRENHEIT SINGLE RESPONSE DEGF |
| Disk Loading Method | SPRING |
| Media for Which Designed | STEAM SECOND RESPONSE |
| Media for Which Designed | AIR FIRST RESPONSE |
| Material | STEEL COMP 316 BODY |
| Material | STEEL COMP 410 STEM |
| Material | STEEL COMP 316 FLOW CONTROL DEVICE |
| Thread Series Designator | NPT ALL ENDS |
| Opening Pressure Setting | 126.0 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 |
| Reference | Meaning |
|---|---|
| 1990C-1 X .75 126PSI | 5/9 Secondary reference Dresser, Inc. Dba Dresser Equipment Group Div Industrial Valve Operations, Dresse |
| 1990 | D/9 Drawing number reference only Dresser, Inc. Dba Dresser Equipment Group Div Industrial Valve Operations, Dresse |
| 3/4 19110LC-2-CC-MS-33-MT/FT | 3/9 Design control — primary reference Dresser, Inc. Dba Dresser Equipment Group Div Industrial Valve Operations, Dresse |
NSN 4820-01-451-2691 is a Valve,safety Relief, classified under FSC 4820, Valves, Nonpowered. Status: active.
Key specifications for 4820-01-451-2691: Flow Control Device: DISK; Furnished Items and Quantity: 1 LEVER; Connection Style: PLAIN,OPTIONAL END(PIPE) SECOND END; Connection Style: PLAIN (PIPE) FIRST END. 25 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.