Annex 16: Pre-accepted Fire Safety Solutions for Small Buildings in Usage Categories 1 and 4
The Danish Building Authority (Bolig- og Planstyrelsen) issued Annex 16 as part of the guidance for Chapter 5 - Fire of the Danish Building Regulations 2018 (BR18). This document provides pre-accepted technical solutions for fire safety in small structures. It applies specifically to buildings classified under Usage Category 1 and Usage Category 4 that consist of a single story above ground with no basement levels. Following these solutions allows developers to document compliance with the safety requirements of BR18 regarding personal safety and the prevention of fire spread to neighboring properties.
The scope of this annex is limited by building size and occupancy. Usage Category 1 includes structures up to 50 m² intended for up to 50 people where no overnight stays occur, such as conservatories, office pavilions, and garden structures. Usage Category 4 covers structures up to 20 m² designed for up to 10 overnight guests, including shelters and small holiday huts. The regulatory framework details requirements for evacuation routes, smoke alarm installations, material classifications, and minimum distances to property boundaries or other buildings on the same site.
The following sections outline the technical requirements for evacuation, fire-technical installations, and construction materials as defined by the Bolig- og Planstyrelsen standards.
Scope and Defined Building Types
The annex applies to specific small-scale buildings categorized by their usage and risk profile. To utilize these pre-accepted solutions, the building must belong to Risk Class 1 or 2 and fall within the following parameters:
- Usage Category 1: Max area of 50 m² and max occupancy of 50 people. Examples include udestuer (conservatories), office pavilions, saunas, and garden pavilions.
- Usage Category 4: Max area of 20 m² and max 10 overnight persons. Examples include overnatningshytter (overnight huts) and shelters.
- Secondary structures: The annex also covers toilet buildings and storage facilities, including steel containers.
Evacuation and Rescue Requirements
In accordance with BR18 § 91, buildings must be designed to ensure safe evacuation. For small buildings under this annex, specific exit and distance rules apply to bypass the need for traditional rescue openings.
- Every living room or habitable space must have at least one exit leading directly to the outside terrain.
- The maximum travel distance from any point in a room to the nearest exit is 10.0 meters.
- If the exit leads through a covered area, the maximum travel distance within that covered space is limited to 8.0 meters.
Smoke Alarms and Technical Installations
Fire technical installations are primarily required for buildings where overnight stays occur. While Usage Category 1 structures have no smoke alarm requirements under this annex, Usage Category 4 structures must comply with BR18 § 93.
- Smoke alarms: Must be installed in all units in Usage Category 4. Battery-powered units are permitted in simple overnight structures.
- Interconnected alarms: If a structure has two levels for sleeping (such as a double-layered shelter), alarms must be installed on both levels and interconnected.
- Exemption for open shelters: Alarms may be omitted in overnight structures with a constant opening of at least 0.5 meters in width and 0.6 meters in height, provided the total opening dimensions meet specific ratios.
Materials and Fire Spread Prevention
To limit the risk of ignition and fire spread, the annex specifies materials and boundary distances. Load-bearing structures in these specific small buildings have no mandatory fire resistance rating, but surface materials must meet specific classifications.
- Surface Materials: Must be at least Class D-s2,d2 (Class B material) or fire-suitable tent canvas.
- Roofing: Acceptable materials include B-roof(t2) (Class T), A2-s1,d0 (Class A), or transparent roof elements of class E-d2.
- Boundary Distance: Buildings with compliant roofing must be placed at least 2.5 meters from property lines or paths. If the roofing is not classified, the minimum distance increases to 10.0 meters.
Frequently Asked Questions
What is the maximum size for a shelter to follow Annex 16?
A shelter or overnight hut in Usage Category 4 must have a maximum area of 20 m² and accommodate no more than 10 people.
Are smoke alarms required in garden pavilions?
No, for buildings in Usage Category 1 (non-overnight use), there are no requirements for fire technical installations like smoke alarms.
What is the maximum travel distance to an exit in these buildings?
The maximum distance from any point within a room to the nearest exit leading to the outside is 10.0 meters.
Can I build a 50 m² office pavilion next to a boundary?
Yes, provided the roofing is classified (e.g., B-roof(t2)), it must be placed at least 2.5 meters from the property boundary or road center.
Do load-bearing walls in these small buildings need a fire rating?
No, this annex states there are no fire resistance requirements for the load-bearing structures of the covered building types.
Are battery-powered smoke alarms allowed in overnight huts?
Yes, the requirement for a smoke alarm system can be satisfied by a battery-powered smoke alarm in simple overnight facilities.
