Fire Door Size Guide

Fire doors are a critical component of any building’s fire safety strategy, designed to stop fire and smoke, providing people with crucial time to evacuate the building safely. However, selecting the right fire door size is not always straightforward. With various standard and custom sizes available, understanding the dimensions and requirements is key to ensuring compliance and effectiveness. This fire door size guide will walk you through everything you need to know about fire door dimensions and regulations.

Why Fire Door Sizes Matter

Fire doors are not one-size-fits-all. Their dimensions play a critical role in their performance during a fire. A properly sized fire door ensures that gaps are minimized, preventing the spread of smoke and flames. Whether you’re working on a residential, commercial, or industrial project, selecting the correct fire door size is vital for meeting building regulations and ensuring safety.

In the UK, fire doors come in a range of standard sizes, but custom dimensions are also available for unique architectural requirements. Understanding these sizes and their applications can help you make informed decisions for your project.

Standard Fire Door Sizes in the UK

Fire doors in the UK typically follow standard dimensions, though these can vary depending on the building’s design and purpose. Here are some of the most common fire door sizes:

1981 x 457/533 x 35mm: Often used for cupboard or wardrobe doors.

1981 x 610/686 x 35mm: Ideal for spaces with restricted wall areas.

1981 x 762 x 35mm: The most common internal door size in England and Wales, often referred to as a 2’6” door.

1981 x 838 x 35mm: Designed to meet Part ‘M’ mobility requirements for wheelchair access, also known as a 2’9” door.

For metric-sized doors, which are increasingly popular in Scotland and Europe, the standard height is 2040mm, with a thickness of 40mm. Common metric sizes include 2040 x 526/626/726/826/926 x 40mm.

Guide To Custom Fire Door Sizes

While standard fire door sizes are widely used, there are instances where custom dimensions are necessary. For example, larger spaces like warehouses, concert halls, or manufacturing facilities may require bespoke fire doors to accommodate wider or taller openings. Reputable suppliers like Fire Resist can manufacture fire doors to meet specific size requirements, ensuring compliance with fire safety standards.

It’s important to note that custom fire door sizes must still meet fire rating specifications, such as FD30 (30-minute fire resistance) or FD60 (60-minute fire resistance). The thickness of the door will vary depending on its fire rating, with FD30 doors typically being 44mm thick and FD60 doors measuring 54mm.

Fire Door Size Guidelines

When selecting a fire door, several factors should be taken into account:

1. Building Regulations and Fire Ratings

Fire doors must meet specific fire ratings based on their location and purpose. These ratings indicate how long the door can withstand fire, smoke, and heat. Common fire ratings include:

• FD20 (20-minute rating): Suitable for areas with lower fire risk. Maximum size: 3’6” (width) x 8’0” (height) for single doors; 7’0” x 8’0” for double doors.
• FD30 (30-minute rating): Commonly used in residential and commercial buildings.
• FD60 (60-minute rating): Ideal for high-risk areas or buildings with longer evacuation times. Maximum size: 3’6” x 8’0” for single doors; 7’0” x 8’0” for double doors.
• FD90 (90-minute rating): Required in high-risk industrial or commercial settings. Maximum size: 3’6” x 8’0” for single doors; double doors are not available.

Each fire rating has specific limitations, such as maximum glass area and jamb requirements. For example:

• Glass Limitations: FD20 doors can have up to 1,296 square inches of fire-rated glass, while FD60 and FD90 doors are limited to 100 square inches.
• Jamb Requirements: FD20 and FD30 doors can use wood jambs, but FD60 and FD90 doors often require steel jambs for double-door applications.

2. Accessibility Requirements

In public buildings or spaces used by individuals with mobility challenges, fire doors must comply with Part ‘M’ of the Building Regulations. This typically requires a minimum door width of 838mm (2’9”) to ensure easy access for wheelchairs and other mobility aids. Wider doors may also be necessary in high-traffic areas or emergency exits.

3. Aesthetic and Functional Needs

While safety is the primary concern, fire doors should also align with the building’s design and functionality. Considerations include:

Design: Fire doors are available in various finishes, including wood, steel, and glass options, to match the building’s aesthetic.

Functionality: Features like automatic door closers, panic bars, and smoke seals can enhance the door’s usability while maintaining safety standards.

Fire Door Size and Weight

The weight of a fire door is directly related to its size and materials. For example, a standard FD30 fire door measuring 1981 x 838 x 44mm and made from Scandinavian redwood weighs approximately 37kg. This weight increases with larger dimensions or higher fire ratings, such as FD60.

Calculating the weight of a fire door is important for ensuring that the frame, hinges, and other components can support it. The formula for calculating the weight of a wooden fire door is:

(Wood Density in kg/m³ x Door Height in mm x Door Width in mm x Door Thickness in mm) / 1,000,000 = Door Weight in kg

For example, let’s break down the calculation for a standard FD30 fire door made from Scandinavian redwood (density: 510 kg/m³) with dimensions of 1981mm (height) x 838mm (width) x 44mm (thickness):

Multiply the density by the dimensions:

• 510 kg/m³ x 1981mm x 838mm x 44mm = 37,252,150,320

Divide by 1,000,000 to convert to kilograms:

• 37,252,150,320 / 1,000,000 = 37.25 kg

This calculation confirms that the door weighs approximately 37.25kg.

It’s important to note that this weight refers only to the door leaf itself. When factoring in additional components such as the frame, hinges, intumescent seals, and hardware, the total weight can increase significantly. For instance, an FD60 fire door, which is thicker (typically 54mm) and made with denser materials, can weigh upwards of 50kg or more, depending on its size.

Fire Door Size Guide for Different Applications

• Residential Buildings: Standard sizes like 1981 x 762mm are commonly used for internal doors, while larger sizes may be required for main entrances or accessible routes.
• Commercial and Industrial Spaces: Larger doors, such as 2040 x 920mm or custom sizes, are often needed to accommodate high traffic or machinery.
• Emergency Exits: Fire doors used as emergency exits must meet specific size and operational requirements, such as being equipped with panic bars for easy egress.

Choosing the Right Fire Door Size

Selecting the correct fire door size involves more than just measuring the opening. It requires a thorough understanding of the building’s layout, fire safety requirements, and the door’s intended use. Properly sized fire doors are essential for ensuring effective fire containment and safe evacuation routes. Here are some key tips to help you choose the right size:

1. Consult Building Regulations

Ensure that the fire door complies with local fire safety standards and building regulations. This includes considering specifications for fire resistance ratings, accessibility requirements, and placement within the building.

2. Measure Accurately

Take precise measurements of the door opening, including the height, width, and thickness. It’s also important to account for frame clearance and ensure that the door fits securely to prevent gaps that could allow smoke or flames to pass through.

3. Consider Future Needs

If the building may require accessibility upgrades in the future, consider installing wider doors that meet Part M requirements for accessibility. This ensures that the fire door will remain compliant if regulations change or accessibility needs increase.

4. Work with Reputable Suppliers

Collaborate with experienced suppliers who can offer tailored advice and high-quality products. Companies like Fire Resist specialize in providing high-quality, certified fireproof doors designed to meet rigorous safety standards. Their expertise ensures you select the correct door size and specification to enhance both fire safety and compliance.

By focusing on these essential factors, you can ensure that your fire doors provide the necessary protection while meeting all safety regulations and long-term building requirements.