The UK Building Regulations encompass various standards to ensure the safety, health, and welfare of individuals in and around built environments. Among these, fire safety is paramount, given its potential to cause loss of life and extensive property damage. This blog sheds light on the fire resistance standards stipulated in the UK Building Regulations, which are vital for minimising fire risks.

What is fire resistance?

Fire resistance refers to a structure’s ability to withstand or restrict its spread. This attribute is also crucial for providing occupants enough time to evacuate and preventing the fire from spreading to neighbouring structures.

Material Resistance

The inherent ability of materials to withstand the heat and flame is critical. Materials are often rated based on their ability to withstand fire exposure while maintaining structural integrity. Common fire-resistant materials include concrete, brick, and certain types of treated wood and metals.

Structural Design

The design of a building plays a vital role in its fire resistance. Elements like firewalls, fire doors, and fire-resistant glazing help to compartmentalise a building, slowing the spread of fire and smoke. The design should also prevent structural collapse, providing more time for evacuation and emergency response.

Compartmentalisation

As mentioned earlier, compartmentalisation is a technique used to divide a building into separate fire-resistant compartments. This helps to contain the fire within a particular area, reducing the overall risk and providing protected escape routes for occupants.

Means of Escape

Buildings must have clear and unobstructed escape routes that can be easily accessed in the event of a fire. These escape routes should also be protected from the spread of fire and smoke to ensure safe evacuation.

Fire Stopping and Sealing

Fire stopping involves sealing any openings and gaps in walls, floors, and ceilings to prevent the passage of fire and smoke. This includes sealing around pipes, ducts, and other service penetrations.

Coatings and Treatments

Certain coatings and treatments can be applied to materials to enhance their fire resistance. For instance, intumescent paint swells when exposed to heat, creating a protective barrier that helps to slow down the spread of fire.

Fire Detection and Alarm Systems

The regulations mandate the installation of fire detection and alarm systems to provide early warning to occupants. The type and coverage of these systems will also depend on the building’s size and use.

Fire Suppression Systems

Besides the passive fire protection measures, active systems like sprinklers and gaseous fire suppression systems can control or extinguish a fire, mitigating the damage and providing additional time for evacuation.

Testing and Certification

Materials and systems used for fire resistance should undergo rigorous testing to ensure they meet the required standards. Certification by recognised bodies provides assurance of a product’s performance in fire situations.

Maintenance

Regular maintenance and inspection are crucial to ensure that the fire resistance measures remain effective over time. This includes checking the integrity of fire doors, seals, and fire-stopping materials, as well as ensuring that fire suppression systems are operational.

UK Regulations – Approved Document B (Fire Safety)

Approved Document B (Fire Safety) is a critical part of the UK Building Regulations, focusing on reducing risks and ensuring safety in case of fire. This document provides statutory guidance on building regulations in England concerning fire safety within and around buildings. It’s separated into two volumes: Volume 1, which covers dwelling houses, and Volume 2, addressing buildings other than dwelling houses.

The document outlines crucial fire safety precautions that must be adhered to, aiming to ensure the safety of occupants, firefighters, and individuals near the building during a fire incident. The guidance within Approved Document B covers various aspects of fire safety including means of escape, fire spread, structural fire protection, and fire service access.

How is it measured?

Fire resistance is measured through a series of tests that evaluate how building materials and assemblies perform under fire conditions. These tests are conducted to determine the fire resistance rating of materials, which is typically expressed in terms of time.

1. Testing:
   • Fire resistance tests: These tests assess how long a material or assembly can maintain its structural integrity and/or insulating ability when exposed to fire. Common tests include the British Standard 476 (BS 476) and the European Standard EN 1363-1.
   • Reaction to fire tests: These tests evaluate how materials contribute to fire growth and spread, often measuring factors like ignitability, flame spread, heat release, and smoke production.
2. Certification:
   • Materials and assemblies that pass fire resistance tests are usually awarded a certification, indicating their fire resistance rating. This certification is crucial for manufacturers and builders to demonstrate compliance with building regulations and standards.
3. Rating:
   • The fire resistance rating is often expressed in terms of time, indicating how long a material or assembly can withstand fire exposure while maintaining its structural integrity and/or insulating ability.

The Euroclass system

The Euroclass system is a European standard used to evaluate the reaction to fire performance of building materials. It’s a comprehensive classification system that provides a clear and precise framework for assessing the fire behaviour of materials.

The Euroclass ratings range from A1 (non-combustible) to F (highly combustible). Materials rated A1 or A2 are typically the most fire-resistant, while materials rated D to F are less resistant to fire. Additionally, the system evaluates the amount of smoke produced (s1, s2, s3) and flaming droplets/particles released (d0, d1, d2) by a material during a fire.

The Euroclass ratings are determined through various tests. This includes the Single Burning Item test (SBI) and the Non-Combustibility test, among others. When choosing insulation boards for external walls, materials with a higher Euroclass rating are advisable for better fire resistance. For instance, Mineral Wool Boards and Calcium Silicate Boards usually achieve high Euroclass ratings due to their inherent fire-resistant properties.