National Marker N351015 Spring Door Hinge 4 In.

Product Description

The NATIONAL MARKER N351015 is a 4-inch spring door hinge finished in oil rubbed bronze, designed for standard residential and light commercial door installations. Built from cold-rolled steel, this hinge provides durable, consistent self-closing performance on hinged doors. The closing speed and tension are both field-adjustable, allowing installers to dial in the right action for the door weight and traffic level. The 5/8-inch radius corner profile fits standard hinge cutouts without modification. It carries UL approval for use on fire-rated doors, making it suitable for applications where code compliance is required.

This spring hinge is used in residential and light commercial settings where self-closing doors are required by code or building specification. Common applications include fire-rated corridor doors, utility room entries, and access doors in commercial tenant spaces. Its standard cutout compatibility makes it a straightforward drop-in replacement during door hardware service or new construction installs.

Key Features

• Adjustable closing speed for field-tuned door action
• Adjustable tension to accommodate varying door weights
• Cold-rolled steel construction for long-term durability
• 5/8-inch radius corners fit standard hinge cutouts without modification
• UL approved for fire-rated door applications
• Oil rubbed bronze finish for consistent appearance on period or transitional hardware sets

Compatibility

Designed as an OEM-style replacement spring hinge for standard door hinge cutouts on residential and light commercial hinged doors. Cataloged as National model V522.

Installation Notes

Installation is typically performed by a carpenter, general contractor, or door hardware technician. Before installation, confirm the door is properly hung and the existing hinge mortise matches the 4-inch leaf size. Tension and closing speed adjustments should be made with the door in place using the manufacturer-provided adjustment tool or a compatible hex wrench. On fire-rated assemblies, verify the completed installation meets the requirements of the applicable fire door assembly listing and local building code.