60 minute fire door knowledge——Class B Fire Door

Guangdun Fire Building Materials Project News

As a leading 60 minute fire door manufacturer in China, Guangdun Door Industry Co., Ltd. is committed to providing high-quality fire safety solutions. Recently, we completed the 2024 Greenfield Fire Safety Materials Procurement and Construction Bidding Project, supplying 592 sets of Class A fire doors, 710 sets of Class B fire doors, along with other fire safety materials like smoke barriers and fire shutter doors. Our involvement in this project underscores our dedication to enhancing fire safety standards across various sectors.

Understanding Class B Fire Doors

A Class B fire door is designed to provide at least 60 minutes of fire resistance. This means that in the event of a fire, a Class B fire door can help prevent the spread of flames and smoke, allowing occupants to evacuate safely. Our Class B fire doors meet rigorous national standards, including GB/T 12955-2008, ensuring stability, integrity, and insulation.

Construction Standards

1. Materials and Components: Our Class B fire doors are constructed from high-quality cold-rolled steel plates, with door frames typically made from 1.2-1.5 mm thick steel and door panels from 0.8-1.2 mm thick. This robust construction ensures durability and effective fire resistance.
2. Installation Requirements: Proper installation is crucial for maximizing the effectiveness of 60-minute fire doors. After installation, gaps between the door and the frame should be minimal, with tight seals to prevent smoke infiltration.
3. Visual and Quality Standards: All fire doors must undergo strict quality checks. Welding must be robust and evenly distributed, while the surface should be free from defects such as rust, dents, or uneven coatings.

Applications of Class B Fire Doors

60 minute fire door are often used in buildings that require fire-resistant barriers, including:

• Entrances to utility rooms and mechanical spaces
• Areas that contain flammable materials
• Locations that need to comply with local fire safety regulations

Our doors are integral to various construction projects, including significant developments such as the revitalization of the Rejuvenation Building, Yihe Hotel, and Jindi Technology Park. These projects showcase our commitment to enhancing fire safety across China, a focus that has been paramount since the founding of the People’s Republic in the 20th century.

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60 minute Fire Door Construction

1. Technical Standards for Class B Fire Doors

The entrance door for this project is designated as FM Class B 1021, which serves as a fire-resistant, theft-proof, and sound-insulating door. The design dimensions for the door opening must be 30 mm smaller than the specifications before installation, and actual dimensions must be confirmed with the client prior to manufacturing. The exterior of the fire door should have edge protection.

2. Door Operation Requirements

• 2.1 Right-Hand Swing Doors: Rotate clockwise for closure (see Figure 1).
• 2.2 Left-Hand Swing Doors: Rotate counterclockwise for closure (see Figure 2).

3. Materials and Components

• 3.1 Frame and Panel Construction: The door frame and panel must be made of cold-rolled thin steel plates. Use steel plates with thicknesses of 1.2 to 1.5 mm for the frame and 0.8 to 1.2 mm for the panel. Reinforcements should also be made from 1.2 to 1.5 mm thick steel, with a minimum thickness of 3.0 mm if threaded holes are present.
• 3.2 Filling Materials: The door panel and frame must be filled with non-combustible materials.
• 3.3 Hardware Standards: Locks, hinges, and other hardware installed on steel fire doors must withstand temperatures of at least 950°C.
• 3.4 Hinges and Closers: Only single-action hinges should be used. Double doors must include cover plates, closers, and sequence devices (excluding normally closed fire doors).
• 3.5 Sealing: The door frame should incorporate a sealing groove filled with non-combustible materials.

4. Appearance Quality

• 4.1 Welding Standards: Welds should be strong and evenly distributed, with no burn-through or weak spots. The exterior surface should be smoothed to eliminate any imperfections.
• 4.2 Coating Standards: The surface of the fire door must be coated with a rust-inhibiting primer, ensuring a smooth, even finish without drips, bubbles, or missed spots.
• 4.3 Surface Defects: Both the door frame and panel must be free from significant dents, scratches, or other visible defects.

5. Dimensional and Geometric Tolerances

When closed, the door leaf should fit snugly against the frame, with a minimum overlap of 10 mm. Measurement points should be at the midpoints of both sides and the top of the door. Maximum gaps should not exceed 4 mm on the sides, 3 mm at the top, and 4 mm between double doors.

6. Fire Resistance Ratings

• 6.1 Class A Fire Doors: Minimum fire resistance of 1.2 hours.
• 6.2 Class B Fire Doors: Minimum fire resistance of 0.9 hours.
• 6.3 Class C Fire Doors: Minimum fire resistance of 0.6 hours.

7. Installation Requirements

1. After installation, the perimeter joints between the fire door and wall should be filled with polyurethane foam and sealed with white caulk.
2. The fire door should operate smoothly and close tightly, with no warping, difficulty in closure, or misalignment issues.
3. Prior to project acceptance, ensure all fire doors are clean and well-maintained.
4. During construction, coordinate with the general contractor and client, ensuring timely cleanup of any debris.

Engineering Department October 10, 2024

Conclusion

At Guangdun Door Industry Co., Ltd., we pride ourselves on our extensive experience and reputation as a trusted fire door manufacturer. With our focus on quality and compliance, we aim to contribute significantly to public safety through our range of fire-resistant products, including our reliable Class B fire doors. For inquiries about our fire door offerings or to discuss your specific needs, please contact us today.

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