The Valve,safety Relief, cataloged under National Stock Number 4820-01-021-7735, is classified within Federal Supply Class 4820 (Valves, Nonpowered) of the Valves group. The manufacturer of record is Anderson Greenwood Lp Dba Anderson Greenwood Crosby. Government technical data includes 19 specifications, cited from the U.S. Government catalog. The record lists 2 manufacturer part numbers 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through both NSN and commercial part number lookups. 1 additional reference document (drawings, advisory and superseded references) is recorded in the U.S. Government catalog.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 | 4820-01-021-7735 |
| Primary Part Number | 171S-1-1-4-165PSI |
| Item Name | Valve,safety Relief |
| FSC / FSG | 4820 / 48 — Valves, Nonpowered |
| Manufacturer | Anderson Greenwood Lp Dba Anderson Greenwood Crosby |
| Status | ACTIVE |
| Flow Control Device | DISK |
| Renewable Seat Ring Type | THREADED |
| Connection Style | PLAIN,OPTIONAL END(PIPE) ALL ENDS |
| Connection Type | THREADED INTERNAL PIPE ALL ENDS |
| Style Designator | ANGLE |
| Material Document and Classification | FED STD 66,AISI 316/SAE 30316 FED STD SINGLE MATERIAL RESPONSE OVERALL |
| Operating Pressure | 400.0 POUNDS PER SQUARE INCH (PSI) MAXIMUM SINGLE RESPONSE LBS |
| Adjustable Pressure Range | +0.0 TO 400.0 POUNDS PER SQUARE INCH LBS |
| Features Provided | PRESSURE TIGHT OUTLET SIDE |
| Bonnet Type | INSIDE SPRING |
| Thread Direction | RIGHT-HAND ALL ENDS |
| Nominal Thread Size | 1.250 INCHES FIRST END IN |
| Maximum Operating Temp | 550.0 FAHRENHEIT SINGLE RESPONSE DEGF |
| Disk Loading Method | SPRING |
| Bonnet Attachment Method | THREADED |
| Material | STEEL COMP 316 OVERALL |
| Thread Series Designator | NPT ALL ENDS |
| Opening Pressure Setting | 165.0 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 |
| Part Number | Manufacturer |
|---|---|
| 171S-1-1-4-165PSI PRIMARY | Anderson Greenwood Lp Dba Anderson Greenwood Crosby (USA) |
| 40M08 | Kaydon Custom Filtration Corporation (USA) |
| Reference | Meaning |
|---|---|
| 171S-1-1-4-165P | C/1 Advisory reference — outside the item-of-supply concept Anderson Greenwood Lp Dba Anderson Greenwood Crosby |
NSN 4820-01-021-7735 is a Valve,safety Relief, manufactured by Anderson Greenwood Lp Dba Anderson Greenwood Crosby, classified under FSC 4820, Valves, Nonpowered. Status: active.
NSN 4820-01-021-7735 has 2 manufacturer part numbers on file: 171S-1-1-4-165PSI (Anderson Greenwood Lp Dba Anderson Greenwood Crosby), 40M08 (Kaydon Custom Filtration Corporation).
Key specifications for 171S-1-1-4-165PSI: Flow Control Device: DISK; Renewable Seat Ring Type: THREADED; Connection Style: PLAIN,OPTIONAL END(PIPE) ALL ENDS; Connection Type: THREADED INTERNAL PIPE ALL ENDS. 19 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.