National Mfg N350-819 4 Inch Ss Spring Door Hinge Ul Fire Door

Product Description

The NATIONAL MFG/SPECTRUM BRANDS HHI N350-819 is a 4-inch stainless steel spring door hinge designed for self-closing door applications. Manufactured from cold rolled steel with a stainless steel finish, it features independently adjustable closing speed and adjustable spring tension, giving installers precise control over door operation after mounting. The square corner design fits standard hinge cutouts without modification. This hinge carries UL approval for use on fire-rated doors, making it a code-compliant choice for commercial and residential applications where fire door hardware is required. Each package contains 2 hinges.

This hinge suits standard interior and fire-rated door installations in residential, light commercial, and multi-family settings. It is commonly specified where building codes or fire safety requirements mandate self-closing hardware on corridor, stairwell, or utility room doors. The adjustable tension and closing speed make it adaptable across a range of door weights and swing frequencies common in these environments. Licensed contractors, carpenters, and door hardware specialists install this type of hardware as part of fire door assembly work.

Key Features

• UL approved for fire-rated door assemblies
• Adjustable closing speed for controlled, consistent door operation
• Adjustable spring tension to accommodate varying door weights
• Fits standard hinge cutout — no mortise modification required
• Square corners for clean fit on standard door and frame preps
• Cold rolled steel construction with stainless steel finish
• Sold as a package of 2 hinges

Compatibility

Designed as an OEM-style replacement or new-installation spring hinge for standard door preparations requiring a 4-inch self-closing hinge on fire-rated or non-rated door assemblies.

Installation Notes

Installation is performed by a licensed carpenter, door hardware specialist, or general contractor following the door manufacturer's fire label requirements. Before adjusting spring tension or closing speed, ensure the door is properly hung and all screws are fully seated. On UL-listed fire doors, do not modify the door or frame in any way that would void the fire label. Consult local building codes and the Authority Having Jurisdiction for fire door hardware requirements prior to installation.