American Market SS304 Fire Rated Two Ball Bearing Door Hinge with UL-DDSS001-FR-4x3.5x3.0mm

1. Certification and fire rating: This product has passed UL/cUL dual certification and meets the requirements of UL 10C standard, with a fire rating of 3 hours. This certification is a necessary condition for the product to enter the North American market, ensuring that your fire door system fully complies with international safety regulations. Each batch of products comes with traceable certification documents, providing buyers with complete compliance proof.

2. Material and process: Made of SS304 stainless steel, this material contains higher nickel and chromium components, and has excellent corrosion resistance and oxidation resistance, with a service life far exceeding that of ordinary 201 stainless steel. The surface has undergone precision mechanical polishing and deburring treatment, presenting a uniform metallic luster that is both aesthetically pleasing and effectively resistant to daily wear and tear.

3. Structure and Size: The product adopts standard dimensions of 4.5 inches by 3.5 inches, with a thickness of 3.5mm to ensure sufficient load-bearing strength. Unique two ball bearing structure design, each bearing is made of high carbon steel material, which has been heat-treated to enhance wear resistance. The hinge pin is designed to be detachable, making it easy to install and adjust the door leaf.

4. Applicable scenarios and supporting facilities: Designed specifically for wooden and steel fire doors, suitable for commercial buildings, hospitals, schools, and other places with high fire safety requirements. It is recommended to use 3-4 hinges per door, and the specific quantity should be determined based on the weight and size of the door leaf. The product provides original stainless steel screws to ensure overall integrity and stability after installation.

1. Innovative design of dual bearings: The core advantage of this UL Door Hing is its unique dual ball bearing structure. Compared with traditional single bearing or bearingless hinges, the dual bearing design can reduce the friction coefficient by more than 70%, making the door leaf opening and closing more lightweight and smooth. Even with long-term use, common problems such as hinge sagging and abnormal noise will not occur, greatly extending the service life of fire doors. This innovative design represents a technological leap in hinge manufacturing, providing buyers with significant product differentiation advantages.

2. Top material guarantee: We insist on using SS304 stainless steel as the raw material, which is in sharp contrast to many products on the market that use carbon steel or low-grade stainless steel. SS304 material not only ensures that the product passes strict salt spray testing (up to 500 hours or more), but also maintains its aesthetic appearance after long-term use. As a manufacturer, we conduct full traceability of raw materials to ensure that every batch of products meets the quality requirements of the North American market. This strict control over materials is our biggest difference from competitors.

1. Preliminary Inspection and Preparation: Upon unpacking, immediately verify the UL certification mark and model identification on the product surface to confirm compliance with your procurement requirements. Count the quantity; typically, each door requires 3-4 UL Door Hinges. Prepare installation tools, including an electric drill, screwdriver, spirit level, and matching installation screws. Check whether the pre-cut dimensions of the door leaf and frame match the hinges, ensuring the installation base is level and secure.

2. Precise Positioning and Marking: Determine hinge placement based on door weight. Typically, the top hinge sits 15-20cm from the door top, the bottom hinge 20-25cm from the door bottom, with the middle hinge centred. Use a spirit level to ensure all mounting points align vertically. Mark drilling positions precisely with a pencil. Accurate positioning directly impacts installation quality and service life.

3. Fitting Hinge Blades: Insert each hinge blade into its respective slot in the door leaf and frame, securing preliminarily with the supplied stainless steel screws. Ensure all hinge bearing holes face the same direction to guarantee correct door swing. Begin fitting from the top hinge and work progressively downward for easier fine-tuning.

4. Door Hanging and Adjustment: Lift the door leaf to align the hinge plates on the door with those on the frame, then insert the hinge pins. Insert the top pin first, followed sequentially by the middle and bottom pins. Verify the door leaf is vertical and operates smoothly. Make fine adjustments by tightening or loosening the adjustment screws as required until optimal performance is achieved.

5. Final Inspection and Testing: Upon completion, conduct comprehensive functional testing. Open and close the door multiple times to check for unusual noises or sticking. Confirm the door remains stable in all positions without self-opening or closing. Finally, verify all screws are securely fastened and advise the user to perform regular inspections and maintenance to ensure this UL Door Hinge consistently delivers optimal performance.