The Valve,safety Relief, cataloged under National Stock Number 4820-01-435-1909, is classified within Federal Supply Class 4820 (Valves, Nonpowered) of the Valves group. The manufacturer of record is Emerson Automation Solutions Final Control Us Lp Div Navy Product Team. Government technical data includes 28 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through both NSN and commercial part number lookups. 2 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog.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 | 4820-01-435-1909 |
| Primary Part Number | 20050K51SS |
| Item Name | Valve,safety Relief |
| FSC / FSG | 4820 / 48 — Valves, Nonpowered |
| Manufacturer | Emerson Automation Solutions Final Control Us Lp Div Navy Product Team |
| Status | ACTIVE |
| Flange Shape | ROUND WITH HOLES ALL ENDS |
| Flange Face Design | RAISED STRAIGHT ALL ENDS |
| Bolt Circle Nominal Diameter | 4.750 INCHES ALL ENDS IN |
| Connection Type | FLANGE ALL ENDS |
| Style Designator | ANGLE FLANGED ENDS |
| Material Document and Classification | ASTM A351, CF8 ASSN STD SINGLE MATERIAL RESPONSE FLOW CONTROL DEVICE |
| Material Document and Classification | ASTM A351, CF8 ASSN STD SINGLE MATERIAL RESPONSE SEAT |
| Material Document and Classification | ATM A216, GR WCB ASSN STD SINGLE MATERIAL RESPONSE BODY |
| Material Document and Classification | QQ-S-764 FED SPEC SINGLE MATERIAL RESPONSE STEM |
| Bolt Hole Nominal Diameter | 0.750 INCHES ALL ENDS IN |
| Operating Pressure | 150.0 POUNDS PER SQUARE INCH (PSI) MAXIMUM SECOND RESPONSE LBS |
| Operating Pressure | 270.0 POUNDS PER SQUARE INCH (PSI) MAXIMUM FIRST RESPONSE LBS |
| Valve Size | 2.000 INCHES IN |
| Adjustable Pressure Range | +66.0 TO 75.0 POUNDS PER SQUARE INCH LBS |
| Maximum Operating Temp | 100.0 FAHRENHEIT FIRST RESPONSE DEGF |
| Maximum Operating Temp | 500.0 FAHRENHEIT SECOND RESPONSE DEGF |
| Second Connection Face to Centerline Distance | 4.750 INCHES IN |
| Nominal Outside Diameter | 6.000 INCHES ALL ENDS IN |
| Bolt Hole Quantity | 4 ALL ENDS |
| First Connection Face to Centerline Distance | 4.750 INCHES IN |
| Material | STEEL UNS J03002 BODY |
| Material | STEEL CORROSION RESISTING STEM |
| Material | STEEL UNS J92600 FLOW CONTROL DEVICE |
| Material | STEEL UNS J92600 SEAT |
| Raised Face Nominal Diameter | 3.620 INCHES ALL ENDS IN |
| Valve Operation Method | AUTOMATIC |
| Raised Face Nominal Height | 0.062 INCHES ALL ENDS IN |
| Nominal Thickness | 0.750 INCHES ALL ENDS IN |
| 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 |
|---|---|
| 20050K51SS PRIMARY | Emerson Automation Solutions Final Control Us Lp Div Navy Product Team (USA) |
| Reference | Meaning |
|---|---|
| 20050 | D/9 Drawing number reference only Anderson Greenwood Lp Dba Anderson Greenwood Crosby |
| 20050K51SS | 5/9 Secondary reference Anderson Greenwood Lp Dba Anderson Greenwood Crosby |
NSN 4820-01-435-1909 is a Valve,safety Relief, manufactured by Emerson Automation Solutions Final Control Us Lp Div Navy Product Team, classified under FSC 4820, Valves, Nonpowered. Status: active.
NSN 4820-01-435-1909 has 1 manufacturer part number on file: 20050K51SS (Emerson Automation Solutions Final Control Us Lp Div Navy Product Team).
Key specifications for 20050K51SS: Flange Shape: ROUND WITH HOLES ALL ENDS; Flange Face Design: RAISED STRAIGHT ALL ENDS; Bolt Circle Nominal Diameter: 4.750 INCHES ALL ENDS IN; Connection Type: FLANGE ALL ENDS. 28 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.