The Valve,safety Relief, cataloged under National Stock Number 4820-01-256-8745, is classified within Federal Supply Class 4820 (Valves, Nonpowered) of the Valves group. The manufacturer of record is Naval Inventory Control Point Mechanicsburg. Government technical data includes 17 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through both NSN and commercial part number lookups. 2 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog.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 | 4820-01-256-8745 |
| Primary Part Number | D841-4052CP |
| Item Name | Valve,safety Relief |
| FSC / FSG | 4820 / 48 — Valves, Nonpowered |
| Manufacturer | Naval Inventory Control Point Mechanicsburg |
| Status | ACTIVE |
| Flow Control Device | DISK |
| Furnished Items and Quantity | 2 TAILPIECE |
| Criticality Code Justification | ZZZY |
| Style Designator | ANGLE |
| Material Document and Classification | ASTM B61 ASSN STD SINGLE MATERIAL RESPONSE BODY |
| Material Document and Classification | ASTM B16 ASSN STD SINGLE MATERIAL RESPONSE FLOW CONTROL DEVICE |
| Material Document and Classification | AISI 303 ASSN STD SINGLE MATERIAL RESPONSE SEAT |
| Material Document and Classification | AISI 303 ASSN STD SINGLE MATERIAL RESPONSE STEM |
| Operating Pressure | 460.0 POUNDS PER SQUARE INCH (PSI) MAXIMUM SINGLE RESPONSE LBS |
| Maximum Operating Temp | 165.0 FAHRENHEIT SINGLE RESPONSE DEGF |
| Disk Loading Method | SPRING |
| Media for Which Designed | OXYGEN, LIQUID SINGLE RESPONSE |
| Material | COPPER ALLOY FLOW CONTROL DEVICE |
| Material | STEEL CORROSION RESISTING SEAT |
| Material | COPPER ALLOY 922 BODY |
| Material | STEEL CORROSION RESISTING STEM |
| Reference Number Differentiating Characteristics | CLEANING, PACKAGING, AND MARKING IAW THE LATEST REVISION OF MIL-STD-1330 |
| Acquisition Status | ACTIVE |
| DEMIL Code | DEMIL A — No Demilitarization Required |
| Hazard | No hazard code in the DLA record (HMIC N) |
| Criticality Code | S |
| Part Number | Manufacturer |
|---|---|
| D841-4052CP | Naval Inventory Control Point Mechanicsburg (USA) |
| Reference | Meaning |
|---|---|
| D841-4052 | 3/1 Design control — primary reference U.S. Government activity |
| D841-4952 | C/1 Advisory reference — outside the item-of-supply concept U.S. Government activity |
NSN 4820-01-256-8745 is a Valve,safety Relief, manufactured by Naval Inventory Control Point Mechanicsburg, classified under FSC 4820, Valves, Nonpowered. Status: active.
NSN 4820-01-256-8745 has 1 manufacturer part number on file: D841-4052CP (Naval Inventory Control Point Mechanicsburg).
Key specifications for D841-4052CP: Flow Control Device: DISK; Furnished Items and Quantity: 2 TAILPIECE; Criticality Code Justification: ZZZY; Style Designator: ANGLE. 17 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.