The Valve,safety Relief, cataloged under National Stock Number 4820-01-350-3685, is classified within Federal Supply Class 4820 (Valves, Nonpowered) of the Valves group. The manufacturer of record is Hamilton Sundstrand Corporation Dba Collins Aerospace. Government technical data includes 13 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through both NSN and commercial part number lookups. 2 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 4820-01-350-3685 |
| Primary Part Number | GS1221-9 |
| Item Name | Valve,safety Relief |
| FSC / FSG | 4820 / 48 — Valves, Nonpowered |
| Manufacturer | Hamilton Sundstrand Corporation Dba Collins Aerospace |
| Status | ACTIVE |
| Flow Control Device | DISK |
| Connection Style | PLAIN,OPTIONAL END(PIPE) ALL ENDS |
| Connection Type | THREADED INTERNAL PIPE ALL ENDS |
| Style Designator | ANGLE |
| Operating Pressure | 3600.0 POUNDS PER SQUARE INCH (PSI) MAXIMUM SINGLE RESPONSE LBS |
| Adjustable Pressure Range | +800.0 TO 1500.0 POUNDS PER SQUARE INCH LBS |
| Thread Direction | RIGHT-HAND ALL ENDS |
| Nominal Thread Size | 0.750 INCHES ALL ENDS IN |
| Maximum Operating Temp | 225.0 FAHRENHEIT SINGLE RESPONSE DEGF |
| Disk Loading Method | SPRING |
| Material | COPPER ALLOY BODY |
| Thread Series Designator | NPT ALL ENDS |
| 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 |
|---|---|
| GS1221-9 | Hamilton Sundstrand Corporation Dba Collins Aerospace (USA) |
| Reference | Meaning |
|---|---|
| GS1221-9 | C/1 Advisory reference — outside the item-of-supply concept U.S. Government activity |
| 637B-9-3/4-2 | 3/9 Design control — primary reference U.S. Government activity |
NSN 4820-01-350-3685 is a Valve,safety Relief, manufactured by Hamilton Sundstrand Corporation Dba Collins Aerospace, classified under FSC 4820, Valves, Nonpowered. Status: active.
NSN 4820-01-350-3685 has 1 manufacturer part number on file: GS1221-9 (Hamilton Sundstrand Corporation Dba Collins Aerospace).
Key specifications for GS1221-9: Flow Control Device: DISK; Connection Style: PLAIN,OPTIONAL END(PIPE) ALL ENDS; Connection Type: THREADED INTERNAL PIPE ALL ENDS; Style Designator: ANGLE. 13 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.