National Stock Number
4820-00-163-8521
National Stock Number (NSN) 4820-00-163-8521, or NIIN 001638521, (valve,safety relief) was assigned January 31, 1973 in the Federal Logistics Information System (FLIS). This NIIN is Available for Manual Assignment. This NSN replaces 1 stock number, 4820012058678.
There are 2 manufacturer part numbers associated with this NSN. None of the associated part number(s) are considered obsolete. The manufacturer part numbers were originally supplied by one supplier. Today, one supplier is listed as an Active supplier for this NSN. Of the active suppliers, only one supplier is deemed design controlled or valid supply parts.
This part number has not been procured by the US Government in over 5 years.
This NSN is somewhat common among different platforms, belonging to 2 different weapons systems.
Based on a planned procurement review by the Primary Inventory Control Activity (PICA) on Jan 02, 2005, this NSN's acquisition method was noted as: Acquire directly from the actual manufacturer, whether or not the prime contractor is the actual manufacturer. The Government physically does not have in its possession sufficient, accurate, or legible data to purchase this part from other than current source(s). (NOTE: This code is applicable only to parts under immediate buy requirements and only as long as the deficiency is under review for resolution and appropriate recoding.) Valid AMCs: 1, 2, 3, 4 and 5.
This NSN is assigned to Item Name Code (INC) 05488. [A VALVE DESIGNED TO AUTOMATICALLY RELEASE EXCESSIVE PRESSURES. IT IS ACTUATED BY STATIC PRESSURE UPSTREAM OF THE VALVE AND IS USED AS A SAFETY VALVE OR RELIEF VALVE, AND MAY BE SET TO CLOSE AT A PREDETERMINED PRESSURE. IT IS NOT DESIGNED FOR REGULATION OF CONTINUOUSLY FLUCTUATING LOADS. IT MAY BE INLINE OR CARTRIDGE (MANIFOLD) DESIGN. EXCLUDES:VALVE (1), RELIEF, PRESSURE AND TEMPERATURE.]. This item does not have a nuclear hardened feature or any other critical feature such as tolerance, fit restriction or application. There is no data in the HMIRS and the NSN is in an FSC not generally suspected of containing hazardous materials. NSN 4820001638521 does not contain precious metals.
This NSN is associated to Schedule B 8481400000: safety or relief valves. The Schedule B End Use is listed as industrial machines, other. NAICS classification category 332911: industrial valve manufacturing.
This information was last updated on Aug 01, 2025.