The Valve,safety Relief, cataloged under National Stock Number 4820-00-073-2255, is classified within Federal Supply Class 4820 (Valves, Nonpowered) of the Valves group. Government technical data includes 30 specifications, cited from the U.S. Government catalog. 2 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 4820-00-073-2255 |
| Item Name | Valve,safety Relief |
| FSC / FSG | 4820 / 48 — Valves, Nonpowered |
| Status | ACTIVE |
| Flow Control Device | POPPET |
| Furnished Items and Quantity | 1 DEFLECTOR CAP |
| Connection Style | PLAIN (PIPE) FIRST END |
| Minimum Operating Temp | -65.0 FAHRENHEIT DEGF |
| Style Designator | STRAIGHT THRU W/BAFFLE |
| Material Document and Classification | FEDSTD66,AISI303/SAE30303 FED STD 1ST MATERIAL RESPONSE AND AMS3304 ASSN STD 2ND MATERIAL RESPONSE FLOW CONTROL DEVICE |
| Material Document and Classification | FEDSTD66,AISI303/SAE30303 FED STD SINGLE MATERIAL RESPONSE BODY |
| Material Document and Classification | FEDSTD66,AISI303/SAE30303 FED STD SINGLE MATERIAL RESPONSE SEAT |
| Nominal Outside Diameter Tube Accommodated | 0.250 INCHES FIRST END IN |
| Operating Pressure | 200.0 POUNDS PER SQUARE INCH (PSI) MAXIMUM SINGLE RESPONSE LBS |
| Adjustable Pressure Range | +10.0 TO 30.0 POUNDS PER SQUARE INCH LBS |
| Bonnet Type | INSIDE SPRING |
| Thread Direction | RIGHT-HAND FIRST END |
| Nominal Thread Size | 0.437 INCHES FIRST END IN |
| Maximum Operating Temp | 400.0 FAHRENHEIT SINGLE RESPONSE DEGF |
| Disk Loading Method | SPRING |
| Surface Treatment | PASSIVATE LOCATION NOT OTHERWISE SPECIFIED |
| Bonnet Attachment Method | INTEGRAL |
| Media for Which Designed | NITROGEN, GASEOUS FIFTH RESPONSE |
| Media for Which Designed | HYDROGEN FOURTH RESPONSE |
| Media for Which Designed | HELIUM THIRD RESPONSE |
| Media for Which Designed | CARBON DIOXIDE SECOND RESPONSE |
| Media for Which Designed | AIR FIRST RESPONSE |
| Thread Class | 3A FIRST END A |
| Material | STEEL COMP 303 SEAT |
| Material | STEEL COMP 303 BODY |
| Material | STEEL COMP 303 AND RUBBER SILICONE CLASS Q FLOW CONTROL DEVICE |
| Thread Series Designator | UNIFIED NATIONAL JOINT FINE (UNJF) FIRST END |
| Opening Pressure Setting | 20.0 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 |
|---|---|
| 202-22500-4-20 | 5/2 Secondary reference U.S. Government activity |
| D524T4D20 | 3/2 Design control — primary reference U.S. Government activity |
NSN 4820-00-073-2255 is a Valve,safety Relief, classified under FSC 4820, Valves, Nonpowered. Status: active.
Key specifications for 4820-00-073-2255: Flow Control Device: POPPET; Furnished Items and Quantity: 1 DEFLECTOR CAP; Connection Style: PLAIN (PIPE) FIRST END; Minimum Operating Temp: -65.0 FAHRENHEIT DEGF. 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.