The Valve,safety Relief, cataloged under National Stock Number 4820-01-189-8741, is classified within Federal Supply Class 4820 (Valves, Nonpowered) of the Valves group. The manufacturer of record is Indal Technologies Inc. Government technical data includes 14 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through both NSN and commercial part number lookups. 2 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog.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 | 4820-01-189-8741 |
| Primary Part Number | 6534C555-1 |
| Item Name | Valve,safety Relief |
| FSC / FSG | 4820 / 48 — Valves, Nonpowered |
| Manufacturer | Indal Technologies Inc |
| Status | ACTIVE |
| Flow Control Device | POPPET |
| Connection Style | PLAIN (TUBE) ALL ENDS |
| Connection Type | THREADED EXTERNAL TUBE FIRST END |
| Operating Pressure | 6000.0 POUNDS PER SQUARE INCH (PSI) MAXIMUM SINGLE RESPONSE LBS |
| Adjustable Pressure Range | +500.0 TO 6000.0 POUNDS PER SQUARE INCH LBS |
| Thread Direction | RIGHT-HAND ALL ENDS |
| Nominal Thread Size | 1.000 INCHES ALL ENDS IN |
| Maximum Operating Temp | 160.0 FAHRENHEIT SINGLE RESPONSE DEGF |
| Media for Which Designed | HYDRAULIC FLUID, PETROLEUM BASE SINGLE RESPONSE |
| Thread Class | 2A ALL ENDS A |
| Thread Quantity Per Inch | 14 ALL ENDS |
| Material | STEEL BODY |
| Thread Series Designator | UNS ALL ENDS |
| Valve Operation Method | MANUAL |
| 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 |
|---|---|
| 6534C555-1 PRIMARY | Indal Technologies Inc (CAN) |
| Reference | Meaning |
|---|---|
| 6534C555-1 | 1/2 Source control — Government-approved source U.S. Government activity |
| 6534C555 | D/9 Drawing number reference only Indal Technologies Inc |
NSN 4820-01-189-8741 is a Valve,safety Relief, manufactured by Indal Technologies Inc, classified under FSC 4820, Valves, Nonpowered. Status: active.
NSN 4820-01-189-8741 has 1 manufacturer part number on file: 6534C555-1 (Indal Technologies Inc).
Key specifications for 6534C555-1: Flow Control Device: POPPET; Connection Style: PLAIN (TUBE) ALL ENDS; Connection Type: THREADED EXTERNAL TUBE FIRST END; Operating Pressure: 6000.0 POUNDS PER SQUARE INCH (PSI) MAXIMUM SINGLE RESPONSE LBS. 14 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.