Fire doors are crucial in preventing the spread of smoke and fire in buildings. However, they can only perform this lifesaving function if installed correctly with fire door hinges that meet strict fire door regulations. A critical aspect of proper fire door installation is using the right size screws to fasten the hinges securely. So what size screws do you need for fire door hinges?
When ensuring fire safety through hardware installation, it is recommended to use either Number 8 or Number 10 wood screws, with a minimum length of 32mm. This specification is crucial for proper fitting and compliance with fire safety standards. Additionally, the HFR014 Ball Bearing Butt Hinge, marked with CE and BS EN1935, exemplifies hardware that meets these requirements.
The Importance of Proper Screw Size for Fire Door Hinges
Choosing screws of the correct size, type, and material is vital for guaranteeing the functionality and fire safety of fire doors. Undersized or substandard screws can compromise the stability of hinges leading to warping, misalignment or even detachment of the door. This destroys the fire door’s integrity and enables flames and smoke to spread rapidly.
Using appropriately sized screws as specified by manufacturers also ensures compliance with building codes and fire safety standards. Failing to adhere to regulations could result in serious legal consequences in the event of fire damage or loss of life. With so much depending on suitable fire door hardware, selecting the right screws is not a matter that should be left to guesswork.
This comprehensive guide provides in-depth information on determining the proper screw size based on key considerations. Follow these best practices for secure and compliant fire door hinge installation.
Fire Door Requirements
| Requirement | Description |
|---|---|
| Material and Construction | Fire doors must be constructed with fire-resistant materials to withstand high temperatures and prevent the spread of fire. |
| Certification | Fire doors must meet specific standards and be certified by a recognized authority, such as the British Woodworking Federation (BWF) or Certifire. |
| Closers and Seals | Fire doors must be equipped with self-closing devices and intumescent seals that expand when exposed to heat. This creates a barrier to prevent the spread of fire and smoke. |
| Signage | Fire doors should have clear and visible “Fire Door Keep Shut” signs to remind individuals not to prop open fire doors. |
| Maintenance | Regular maintenance and inspections are mandatory to ensure fire doors function correctly. Any defects should be repaired promptly. |
Factors That Determine Appropriate Screw Size
Choosing screws for fire door hinges entails taking into account several interdependent factors:
Fire Door Type and Dimensions
- Fire resistance rating (integrity rating like FD30, FD60)
- Minimum thickness and density required for rating
- Material (solid timber, metal, composite)
- Weight and dimensions
Hinge Specifications
- Type (butt, ball bearing, spring)
- Dimensions and gauge
- High-grade material (steel, stainless steel, brass)
- Load bearing capacity as per fire door weight
- Certification marks (CE, UL)
Frame and Wall Construction
- Material (wood, metal, masonry)
- Depth and density
Getting the right combination ensures longevity. Now let’s look at how these factors relate to screw sizing.
Standard Screw Sizes for Fire Door Hinges
While hinge manufacturers may recommend specific screw models, some general guidelines apply:
Screw Gauge
The gauge indicates the screw’s diameter. Standard gauges include:
- #6 – 3.5mm diameter (not preferred for fire doors)
- #8 – 3.8mm diameter (most common)
- #10 – 4.2mm diameter (for heavy doors)
Typically, #8 and #10 gauges are used for timber and steel fire doors. The larger gauge provides a more secure grip.
Screw Length
Common lengths are:
- 32mm
- 40mm
- 50mm
The length depends on the depth of the pilot hole drilled into the wall material so the screw can grab firmly.
Screw Material
Look for screws with the same material as the hinges, like:
- Steel
- Stainless steel
- Brass
Matching materials ensures stability and avoids corrosion.
Now, look at best practices for positioning and installing hinges securely.
Fire Door Ratings
| Fire Door Rating | Description |
|---|---|
| 20 Minutes | Fire doors with a 20-minute rating are typically installed in areas where smoke and drafts are the primary concern. |
| 1/3 Hour | Fire doors with this rating can withstand a fire for 20 minutes, offering increased protection. |
| 3/4 Hour | Fire doors with this rating provide a 45-minute fire resistance period, making them suitable for applications requiring higher protection. |
| 1 Hour | A 1-hour-rated fire door can endure the heat of a fire for a full hour before losing its integrity. |
| 1 1/2 Hours | This rating extends the fire resistance period to 90 minutes, offering enhanced protection for critical applications. |
| 3 Hours | Fire doors with a 3-hour rating are the most resilient, ensuring protection for an extended 180-minute duration. |
Hinge Positioning and Quantity Guidelines
Correctly positioning fire door hinges improves stability and sealing. Follow these standards:
- Place the topmost hinge 100mm down from the door top
- Position the bottom hinge 100-200mm up from the bottom
- Ensure the middle hinge is the central indoor height or slightly above the centre
- Use a minimum 3 hinges up to 2040mm in height; add 1 more for every 500mm extra door height
Adjust positioning to account for non-standard doors. Also, consider adding more hinges or using heavy-duty models for overweight doors.
Pro Tips for Secure and Durable Installation
Follow these professional recommendations when installing fire door hinges:
Pre-drill Holes
Always pre-drill screw holes into the frame and wall material rather than driving them directly. This prevents cracking or splintering of the substrate.
Power Tools vs Manual Installation
While powered drills make installation faster, using manual screwdrivers allows better control of the torque applied. Avoid overtightening screws.
Ensure Snug Fit
Make sure screw heads sit flush within recessed slots on hinge blades without any gap or wobble.
Troubleshooting Common Fire Door Hinge Issues
Sometimes, hardware issues can arise over time. Be alert for these signs of problems related to screws:
Stripped Screw Holes
Excessive tightening or movement can wear out the substrate causing screws to lose grip. Fill holes with matchsticks and reposition the hinge slightly.
Misaligned Hinges
This causes binding or an incomplete seal. Try adjusting with longer/thicker screws. If severe, replace damaged hinges.
Worn Out Screws
Look for rusting, bent screws or loose fit. Replace damaged screws with new ones meeting specifications.
NFPA 80 Requirements for Hinges
| Requirement | Description |
|---|---|
| Type of Fasteners | Steel machine screws must be used to secure mortise hinges to reinforcements in a door. |
| Labelling | Spring hinges must be labelled and meet the Grade 1 standards of A156.17. |
| Hinge Types | Annex A of NFPA 80 references various types of hinges, including 5-, 3-, and 2-knuckle hinges, full-mortise, half-mortise, full-surface, and half-surface hinges, spring hinges, wide-throw, raised-barrel, and swing-clear designs. |
| Minimum Hinge Size | The minimum hinge size, type, and thickness should be based on the door rating, width, and height. |
| Quantity of Pivots | A pivot set consisting of a top and bottom pivot is required for doors up to 90 inches in height, with an additional intermediate pivot for each additional 30 inches or a fraction thereof. |
| Ball Bearing Type | All hinges or pivots, except spring hinges, must be ball-bearing. |
| Hardware Industry Standards | Table 2-8A of the National Fire Protection Association (NFPA) handbook No. 80 sets forth the minimum quantity, size, and weight (thickness) for swinging fire doors. |
Conclusion and Key Takeaways
Installing suitable screws to fasten fire door hinges properly is imperative for the safe and compliant functioning of fire doors. Use screws meeting specifications based on door/hinge type and dimensions. Position hinges accurately based on standards and follow best practices for durable installation. Inspect periodically and replace worn screws.
Adhering to manufacturer guidelines and building codes for screw sizing, hinge models, material choice, and placement is essential to prevent voiding certification and compromising fire safety. Paying attention to these details guarantees maximum life and performance for the vital fire protection role of these specialized doors.
Frequently Asked Questions
Can I use regular screws for fire door hinges?
No, you should always use screws specifically designed and tested for fire doors as per manufacturer specifications. Regular screws may not provide adequate strength.
Is there a specific type of screw required for fire doors?
Yes, most manufacturers recommend high-grade steel screws in larger gauge sizes like #8 or #10 and minimum lengths of 30mm to 50mm for secure fastening.
How do I know if my fire door hinges have the correct screws?
Check if the screw type and size are marked on the hinge according to the standards it is certified to. Also, ensure screws are in good condition with proper fit and alignment.
What happens if I use the wrong size screws for fire door hinges?
The hinges may fail prematurely, leading to misalignment, loose fittings, or detachment in case of fire. This destroys the fire rating and safety functionality.
Where can I find the recommended screw size for my specific fire door hinges?
Always refer to the manufacturer’s installation instructions. Check technical specifications or contact the hardware supplier directly if they are unavailable.
Are there any visual signs that I need to replace the screws on my fire door hinges?
Look for rust, bending, wear and tear, or heads that do not fit flush within recessed slots. These indicate a loss of structural stability necessitating replacement.
Do the screws need to be the same material as the hinges?
Ideally, yes, to prevent corrosion and ensure durable performance. For example, stainless steel screws for stainless hinges. Exceptions may apply in certain conditions.
References and Further Reading
- British Standards Institution. Code of Practice for Fire Door Assemblies. BSI Standards Publication, 2021.
- National Fire Protection Association. Standard for Fire Doors and Other Opening Protectives. NFPA 80, 2022.
- American National Standards Institute. Standard for Swinging Fire Doors. ANSI/BHMA A156.14, 2021.
- Builders Hardware Manufacturers Association. What You Need to Know About Fire Door Hinges. BHMA, 2020.
Academic papers:
Doors with Specific Fire Resistance Class – This paper discusses fire doors’ fire resistance, including requirements, testing methodology, and classification. While it focuses on the thermal insulation of fire door sets. How they’re tested depending on the structure type and side of fire exposure indirectly suggests that the structural integrity, including screw size, could be critical (Izydorczyk et al., 2017).
Strength and durability of furniture drawers and doors – Although focused on furniture, this study explores the strength and durability of drawers and doors, including the impact of different kinds of sleeves, connecting links, and the moments of drive-in values on strength. It emphasizes the importance of screw mounting in plastic sleeves for better durability and strength, which might be relevant for fire door hinges as well (Smardzewski & Majewski, 2013).
Finite Element Method Simulations to Improve Press Formability of Door Hinge – This article details a method to improve the press formability of a door hinge through changes in the shape of the blank area based on finite element method (FEM) simulations. It focuses on reducing stress and strain during forming, which could influence considerations for screw size and placement in fire door hinges to prevent cracks or structural failure (Nguyen Duc Toan et al., 2009).
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I'm James Davis, a carpenter with eight years of experience in carpentry services, repairs, installations, renovations, and maintenance of interior doors. I have a diploma in carpentry and joiner trade from the Education Skills Australia Institute and take pride in delivering high-quality results to ensure customer satisfaction. I'm a blog writer for Octopus Doors Company and enjoy sharing my knowledge and tips on maintaining security measures and choosing the right door materials, paints, or handle styles. I specialize in custom-made interior doors and strive to make every home look fabulous. Contact me anytime for help with door-related issues.