The Valve,check, cataloged under National Stock Number 4820-01-421-2587, is classified within Federal Supply Class 4820 (Valves, Nonpowered) of the Valves group. The manufacturer of record is William E Williams Valve Corp. Government technical data includes 26 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through both NSN and commercial part number lookups. 1 additional reference document (drawings, advisory and superseded references) is recorded in the U.S. Government catalog. Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 4820-01-421-2587 |
| Primary Part Number | B15SW 2 1/2IN |
| Item Name | Valve,check |
| FSC / FSG | 4820 / 48 — Valves, Nonpowered |
| Manufacturer | William E Williams Valve Corp |
| Status | ACTIVE |
| Flow Control Device | DISK |
| Flange Shape | ROUND WITH HOLES ALL ENDS |
| Flange Face Design | PLAIN ALL ENDS |
| Bolt Circle Nominal Diameter | 5.500 INCHES ALL ENDS IN |
| Mounting Position | HORIZONTAL OR VERTICAL |
| Connection Type | FLANGE ALL ENDS |
| Style Designator | STRAIGHT THRU FLANGED ENDS |
| Material Document and Classification | ASTM B62 ASSN STD SINGLE MATERIAL RESPONSE BODY |
| Material Document and Classification | ASTM B62 ASSN STD SINGLE MATERIAL RESPONSE SEAT |
| Material Document and Classification | ASTM B62 ASSN STD SINGLE MATERIAL RESPONSE FLOW CONTROL DEVICE |
| Bolt Hole Nominal Diameter | 0.875 INCHES ALL ENDS IN |
| Operating Pressure | 150.0 POUNDS PER SQUARE INCH (PSI) MAXIMUM FIRST RESPONSE LBS |
| Operating Pressure | 225.0 POUNDS PER SQUARE INCH (PSI) MAXIMUM SECOND RESPONSE LBS |
| Valve Size | 2.500 INCHES IN |
| Maximum Operating Temp | 406.0 FAHRENHEIT FIRST RESPONSE DEGF |
| Maximum Operating Temp | 150.0 FAHRENHEIT SECOND RESPONSE DEGF |
| Nominal Outside Diameter | 7.000 INCHES ALL ENDS IN |
| Bolt Hole Quantity | 4 ALL ENDS |
| Face to Face Distance | 8.500 INCHES IN |
| Media for Which Designed | WATER-OIL-GAS SECOND RESPONSE |
| Media for Which Designed | STEAM FIRST RESPONSE |
| Material | COPPER ALLOY 836 BODY |
| Material | COPPER ALLOY 836 SEAT |
| Material | COPPER ALLOY 836 FLOW CONTROL DEVICE |
| Valve Operation Method | AUTOMATIC |
| Nominal Thickness | 0.563 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 |
|---|---|
| B15SW 2 1/2IN PRIMARY | William E Williams Valve Corp (USA) |
| Reference | Meaning |
|---|---|
| B15SW-2.50IN | C/1 Advisory reference — outside the item-of-supply concept William E Williams Valve Corp |
NSN 4820-01-421-2587 is a Valve,check, manufactured by William E Williams Valve Corp, classified under FSC 4820, Valves, Nonpowered. Status: active.
NSN 4820-01-421-2587 has 1 manufacturer part number on file: B15SW 2 1/2IN (William E Williams Valve Corp).
Key specifications for B15SW 2 1/2IN: Flow Control Device: DISK; Flange Shape: ROUND WITH HOLES ALL ENDS; Flange Face Design: PLAIN ALL ENDS; Bolt Circle Nominal Diameter: 5.500 INCHES ALL ENDS IN. 26 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.