Bygningsreglementets vejledning til kap 5 – Brand: Chapter 4 – Guidance on Ignition and Fire Spread
The official document Bygningsreglementets vejledning til kap 5 - Brand, specifically Kapitel 4: Antændelse, brand- og røgspredning, is a regulatory guidance paper issued by the Danish Transport, Construction and Housing Authority (Trafik-, Bygge- og Boligstyrelsen). Published on January 15, 2021, it provides technical interpretations and pre-accepted solutions for the functional requirements set out in the Danish Building Regulations 2018 (BR18), specifically sections §§ 104-125. The document serves as a compliance framework for architects, engineers, and developers to ensure buildings are designed to minimize the risk of fire start and limit the subsequent spread of fire and smoke.
The scope of Chapter 4 covers the regulation of building materials, structural components, and technical installations. It defines requirements for internal and external surfaces, suspended ceilings, heating systems, and the division of buildings into fire cells (brandceller) and fire sections (brandsektioner). The guidance utilizes the European classification system according to DS/EN 13501-2, focusing on performance criteria such as Integrity (E) and Insulation (I). It applies to various building categories, from residential dwellings to high-rise structures and industrial warehouses, establishing specific thresholds for fire resistance and safety distances.
This guidance detail how to document compliance through standardized solutions or technical fire documentation. The following sections outline the specific regulatory standards for building components, compartmentation, and material properties as defined in the document.
Risk of Ignition and Technical Installations
The regulation mandates that installations with a specific risk of ignition must be placed and designed to minimize fire hazards according to BR18 §105. This includes waste rooms, charging stations, and heating systems.
- Electrical Panels: Non-layman operated panels must be placed in a separate fire cell. Small sub-panels in escape routes must be housed in closed steel cabinets.
- Heating Systems: Systems such as pellet boilers or fireplaces must maintain specific distances to combustible materials, often determined by CE-marking or a minimum of 375 mm for smoke pipes.
- Flooring Protection: Floors under solid fuel stoves must be covered by non-combustible material (minimum class A2-s1,d0) extending 300 mm in front of closed stoves and 500 mm in front of open fireplaces.
Internal Surfaces and Linings
Internal surfaces in rooms and escape routes must not contribute significantly to fire spread during the time required for evacuation. Requirements vary by building application category as specified in Table 1.
- Wall and Ceiling Linings: Most categories require at least class K1 10 / B-s1,d0 (Class 1 lining).
- Flooring: In escape routes and stairs, flooring must meet at least class Dfl-s1 (Class G flooring).
- Acoustics and Trim: Trim and acoustic regulation may be mounted on surfaces if they possess the same fire technical properties as the underlying lining.
Fire Compartmentation and Building Division
Buildings must be divided into fire units to ensure escape routes remain usable. The document distinguishes between fire cells and fire sections.
- Fire Cells (Brandceller): Designed to prevent spread during the initial evacuation phase. A fire cell generally cannot span more than 2 floors unless it is under 150 m².
- Fire Sections (Brandsektioner): Larger units designed to limit fire size and protect rescue paths. Maximum sizes for un-sprinklered office sections are 5,000 m², increasing to 10,000 m² if sprinklered.
- Fire Walls (Brandvæg): Walls at property lines or between large sections must meet class REI 120 A2-s1,d0 to ensure stability from both sides during a fire.
External Surfaces and Roofs
External walls and roofs are regulated to prevent vertical fire spread and fire transmission between buildings on the same or neighboring plots.
- Facade Distance: For buildings up to 22 meters, facades usually require class K1 10 / B-s1,d0. The minimum distance to property lines is 2.5 meters for standard linings.
- Thatched Roofs (Stråtag): Due to high risk, buildings with thatched roofs must be placed at least 10 meters from property boundaries.
- Vertical Fire Spread: At balconies, spread is restricted by using non-combustible undersides (class A2-s1,d0) with a melting point above 850 degrees Celsius.
Insulation Material Classification
The use of insulation is restricted based on the material's fire reaction class and the building's height and use.
- Class A2-s1,d0: Non-combustible materials can be used without restrictions.
- Class B-s1,d0: Generally allowed in buildings where the top floor is maximum 22 meters above terrain.
- Class D-s2,d2: Limited to lower buildings or when specific covering requirements (e.g., class EI 30) are met to prevent early ignition.
Frequently Asked Questions
What fire class is required for a fire wall at a property line?
A fire wall located closer than 2.5 meters to a property line must be constructed as a class REI 120 A2-s1,d0 (BS-bygningsdel 120) component.
How large can a fire section for an office building be?
According to Table 4, an un-sprinklered fire section for an office in a single-story building can be up to 5,000 m², or 10,000 m² if a sprinkler system is installed.
What are the rules for electrical panels in escape routes?
Electrical panels must be placed in a separate fire cell unless they are for layperson use, in which case small panels can be placed in escape routes if they are in closed steel cabinets.
How far must a thatched roof be from the neighbor's property line?
Buildings with roof coverings inferior to class BROOF(t2), such as thatched roofs, must be placed at least 10 meters from the property line.
What is the requirement for internal wall linings in most buildings?
Most rooms and escape routes require a wall lining that meets at least class K1 10 / B-s1,d0, also known as a Class 1 lining.
Can a fire cell span multiple floors?
Normally, a fire cell is limited to 2 floors; however, it can span more than 2 floors if the total floor area does not exceed 150 m².
What distance is required between a smoke pipe and combustible material?
If not specified by CE-marking, a smoke pipe must have a distance of 3 times its nominal diameter, but at least 375 mm, from combustible materials.
