The Valve,safety Relief, cataloged under National Stock Number 4820-01-302-1887, is classified within Federal Supply Class 4820 (Valves, Nonpowered) of the Valves group. The manufacturer of record is Naval Sea Systems Command. Government technical data includes 16 specifications, cited from the U.S. Government catalog. The record lists 2 manufacturer part numbers 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through both NSN and commercial part number lookups. 1 additional reference document (drawings, advisory and superseded references) is recorded in the U.S. Government catalog.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 | 4820-01-302-1887 |
| Primary Part Number | 5550531-1 |
| Item Name | Valve,safety Relief |
| FSC / FSG | 4820 / 48 — Valves, Nonpowered |
| Manufacturer | Naval Sea Systems Command |
| Status | ACTIVE |
| Flow Control Device | POPPET |
| Connection Style | PLAIN (PIPE) FIRST END |
| Connection Type | THREADED EXTERNAL PIPE FIRST END |
| Style Designator | STRAIGHT THRU NOTE: TO BE USED FOR VALVE BODIES OF ONE SECTION ONLY. |
| Thread Direction | RIGHT-HAND ALL ENDS |
| Nominal Thread Size | 0.750 INCHES ALL ENDS IN |
| Media for Which Designed | ACETYLENE SECOND RESPONSE |
| Media for Which Designed | HYDROGEN FIFTH RESPONSE |
| Media for Which Designed | AMMONIA, GASEOUS THIRD RESPONSE |
| Media for Which Designed | AIR FIRST RESPONSE |
| Media for Which Designed | REFRIGERANT 12 FOURTH RESPONSE |
| Material | RUBBER BUTADIENE-ACRYLONITRILE CLASS NBR SEAT |
| Material | STEEL COMP 303 BODY |
| Thread Series Designator | NPT FIRST END |
| Opening Pressure Setting | 90.0 POUNDS PER SQUARE INCH LBS |
| 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 |
NSN 4820-01-302-1887 is a Valve,safety Relief, manufactured by Naval Sea Systems Command, classified under FSC 4820, Valves, Nonpowered. Status: active.
NSN 4820-01-302-1887 has 2 manufacturer part numbers on file: 5550531-1 (Naval Sea Systems Command), 5550531 (Naval Sea Systems Command).
Key specifications for 5550531-1: Flow Control Device: POPPET; Connection Style: PLAIN (PIPE) FIRST END; Connection Type: THREADED EXTERNAL PIPE FIRST END; Style Designator: STRAIGHT THRU NOTE: TO BE USED FOR VALVE BODIES OF ONE SECTION ONLY.. 16 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.