The Valve,safety Relief, cataloged under National Stock Number 4820-01-238-0156, is classified within Federal Supply Class 4820 (Valves, Nonpowered) of the Valves group. The manufacturer of record is Watson Mcdaniel Co. 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through both NSN and commercial part number lookups. 1 additional reference document (drawings, advisory and superseded references) is recorded in the U.S. Government catalog. Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 4820-01-238-0156 |
| Primary Part Number | TYPE R 1/2IN 25T100PSI |
| Item Name | Valve,safety Relief |
| FSC / FSG | 4820 / 48 — Valves, Nonpowered |
| Manufacturer | Watson Mcdaniel Co |
| Status | ACTIVE |
| Flow Control Device | BALL |
| Connection Style | PLAIN,OPTIONAL END(PIPE) ALL ENDS |
| Connection Type | THREADED INTERNAL PIPE ALL ENDS |
| Style Designator | ANGLE |
| Operating Pressure | 300.0 POUNDS PER SQUARE INCH (PSI) MAXIMUM SINGLE RESPONSE LBS |
| Adjustable Pressure Range | +25.0 TO 100.0 POUNDS PER SQUARE INCH LBS |
| Bonnet Type | INSIDE SCREW |
| Thread Direction | RIGHT-HAND ALL ENDS |
| Nominal Thread Size | 0.500 INCHES ALL ENDS IN |
| Maximum Operating Temp | 300.0 FAHRENHEIT SINGLE RESPONSE DEGF |
| Bonnet Attachment Method | THREADED |
| Media for Which Designed | WATER-OIL-GAS SECOND RESPONSE |
| Media for Which Designed | AIR FIRST RESPONSE |
| Material | COPPER ALLOY BODY |
| Material | STEEL CORROSION RESISTING FLOW CONTROL DEVICE |
| 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 |
|---|---|
| TYPE R 1/2IN 25T100PSI PRIMARY | Watson Mcdaniel Co (USA) |
| Reference | Meaning |
|---|---|
| 10089 1/2IN 25T | C/1 Advisory reference — outside the item-of-supply concept Watson Mcdaniel Co |
NSN 4820-01-238-0156 is a Valve,safety Relief, manufactured by Watson Mcdaniel Co, classified under FSC 4820, Valves, Nonpowered. Status: active.
NSN 4820-01-238-0156 has 1 manufacturer part number on file: TYPE R 1/2IN 25T100PSI (Watson Mcdaniel Co).
Key specifications for TYPE R 1/2IN 25T100PSI: Flow Control Device: BALL; Connection Style: PLAIN,OPTIONAL END(PIPE) ALL ENDS; Connection Type: THREADED INTERNAL PIPE ALL ENDS; 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.