Bilag 1a: Fire Safety for Single-Family Houses – Danish Building Regulations (BR18) Pre-accepted Solutions
The Bilag 1a - Præ-accepterede løsninger for fritliggende og sammenbyggede enfamiliehuse is a statutory guidance document issued by the Bolig- og Planstyrelsen (Danish Authority of Social Services and Housing). It functions as part of the wider legal framework of the Bygningsreglementet 2018 (BR18), specifically supporting the requirements for fire safety in Chapter 5. This version 2.0, dated 03-01-2022, provides standardized technical solutions that, when followed, document compliance with national fire safety standards for residential structures.
The scope of this document covers detached and terraced single-family houses, including summer houses and integrated secondary structures like garages or carports, provided they fall under anvendelseskategori 4 (usage category 4) and risikoklasse 1 (risk class 1). It defines specific thresholds for building geometry, such as a maximum of 3 stories above ground level and 1 story below ground, with a floor height of the top story not exceeding 9.6 meters. The regulatory framework addresses documentation requirements, evacuation paths, load-bearing capacities, and the prevention of fire spread to neighboring properties.
Professional users, including architects and structural engineers, use these pre-accepted solutions to determine if a project can be classified as brandklasse 1 or brandklasse 2. This classification dictates whether a certified fire consultant is required and the extent of documentation needed for the building permit and final completion notice.
Building Classifications and Scope
Buildings governed by this annex must meet the criteria for Risikoklasse 1 (Risk Class 1) as defined in BR18. This classification applies to structures where occupants are familiar with escape routes and can bring themselves to safety.
- Usage Category 4: Residential units with sleeping areas where occupants are capable of self-evacuation.
- Risk Class 1: Maximum 3 stories above ground, 1 below ground, and a maximum total area of 600 m².
- Fire Class 1: Projects following these pre-accepted solutions in full with a total area under 600 m².
- Fire Class 2: Projects exceeding 600 m² or requiring minor deviations, necessitating a certified fire consultant.
Evacuation and Rescue Requirements
Evacuation strategies are based on limited walking distances and the provision of rescue openings to allow for person rescue by the emergency services or self-evacuation.
- Gangafstand (Walking Distance): Maximum 30 meters from any point in the house to an exit leading directly to the terrain.
- Redningsåbninger (Rescue Openings): Every fire cell must have at least one rescue opening if there is no direct terrain exit.
- Dimensions: Rescue openings must have a combined height (h) and width (b) of at least 1.5 m, with a minimum height of 0.6 m and minimum width of 0.5 m.
- Smoke Alarms: At least one smoke alarm must be installed in every fire cell, connected to the building's permanent power supply with battery backup.
Load-Bearing Structures and Fire Resistance
Load-bearing elements must maintain stability during a fire to ensure safe evacuation and emergency service intervention. The standard requirement is a fire resistance of at least 30 minutes (R30).
- General Structures: Load-bearing walls and floors must meet class R30 [BD-bygningsdel 30].
- Three-Story Buildings: For houses with three stories and an area over 150 m², basement ceilings and supporting structures must meet R60 / A2-s1,d0 [BS-bygningsdel 60].
- Roof Structures: No fire resistance requirement is placed on rafters in uninhabitable roof spaces, provided they do not support other load-bearing parts.
Fire Spread and Boundary Distances
To prevent fire spread between buildings and across property lines, the document specifies minimum distances based on cladding materials and roofing types.
- Standard Distance: Minimum 2.5 meters to the property boundary, road, or path center for buildings with Klasse T roofing.
- Combustible Materials: Buildings with thatched roofs (stråtag) require a minimum distance of 10.0 meters from the boundary unless fire-secured.
- Integrated Garages: Garages and carports under 50 m² must be fire-separated from the primary dwelling by a construction meeting at least EI 30 [BD-bygningsdel 30].
Frequently Asked Questions
What is the maximum walking distance to an exit in a single-family house?
The maximum walking distance from any point in the house to an exit door leading to the outside is 30 meters.
What are the required dimensions for a rescue opening?
The sum of the clear height and clear width must be at least 1.5 meters, with the height being at least 0.6 meters and the width at least 0.5 meters.
Must smoke alarms be connected to the mains power?
Yes, smoke alarms in new dwellings must be connected to the building's fixed power supply and include a battery backup.
What is the minimum distance to a property boundary for a house with a standard roof?
The minimum distance to the property boundary, or the center of a road or path, is 2.5 meters for houses with Klasse T (BROOF(t2)) roofing.
What is the fire resistance requirement for load-bearing walls in a standard house?
Load-bearing walls must generally meet the fire resistance class R30 (formerly BD-30).
How is the area of a basement calculated for fire classification?
A basement is counted as a story if the ceiling is more than 1.25 meters above the surrounding terrain.
What is a DKV-plan?
It is an Operation, Control, and Maintenance plan (Drift-, Kontrol- og Vedligeholdelsesplan) that the building owner must maintain to ensure fire safety systems remain functional.
Can a house with a thatched roof be built closer than 10 meters to a boundary?
If the thatched roof is not fire-secured, the minimum distance is 10.0 meters; if it is fire-secured according to section 4.5.1.3, the distance may be reduced to 5.0 meters.
