Building and buying

Structural fire protection for your single-family house: regulations to observe

Arne Schätzle

Around 20,000 buildings catch fire every year, and a residential fire breaks out every 40 minutes in Switzerland, according to statistics from the Swiss Cantonal Fire Insurance Association. Anyone who is planning and building a house cannot ignore the topic of structural fire protection.

A house is burning behind some trees. Only the remains of the roof truss can be seen.
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In this article

How structural fire protection is regulated in Switzerland

Your house offers security for the whole family. You turn it into a loving home and like inviting friends to share it with you. We want to protect this place as much as possible – and we even have an obligation to do so, according to fire safety regulations.

Article 1 of Swiss fire safety regulations puts it like this: “The purpose of fire safety regulations is to protect people, animals and property from the dangers and effects of fires and explosions. They lay down the legal obligations necessary for this purpose.”

Two institutions are responsible for the structural fire protection of buildings in Switzerland: the cantons issue the relevant laws, regulations, ordinances, decrees, enforcement provisions and directives, while the Swiss Cantonal Fire Insurance Association (VKF) draws up the fire protection regulations. As the umbrella organization of the 19 cantonal building insurance companies in Switzerland, the VKF is the coordination center for fire protection and the prevention of damage resulting from natural disasters.

It’s true that fire safety regulations are not easy to take in: the regulations are not exactly light reading. But don’t worry, we will guide you through the jungle of paragraphs so that you have all the information you need to start planning and coordinating with architects and building planners.

Leading the way in structural fire protection regulations: the VKF

The VKF fire protection standards govern specific requirements in terms of fire protection and are legally binding in all cantons. The VKF last revised the fire protection regulations in 2015. You can consult the complete guidelines in French, German and Italian on the VKF website and download them as PDF files.

Single-family houses: only a few fire safety regulations

Fire protection regulations are always based on the use and size of the building. It makes sense to have different fire protection measures for single-family houses than for industrial plants or hotels.

Single-family houses, whether detached, semi-detached or terraced, belong to the category of “buildings with small dimensions”. The good news for houses in this class is that they only have to satisfy a few fire protection requirements.

There are no special requirements for the fire resistance of the supporting structure or of doors, stairs and corridors. You may use any approved building materials. The only exceptions are rooms with a so-called increased fire risk. This is usually the boiler room. The official regulations refer in this case to rooms in which combustion aggregates with solid fuels such as chip or pellet heaters are installed. These must be separated at least with building materials of fire resistance standard “EI 30”. We explain below exactly what this means.

A single-family house with a modern extension.

Whether a single-family house is a free-standing building, has an extension or is part of a row of houses, it belongs to the category of “small buildings”, which are only subject to low fire protection requirements.

Fire protection regulations applicable to building materials

What do these regulations mean for you as a contractor or owner? In principle you may use any approved building materials. Building materials are divided into fire behavior groups, which are abbreviated as “RF” – from the French “réaction au feu”. The crucial factors in this classification are flammability, flame propagation and release of heat:

  • Fire behavior group
  • Fire contribution
  • RF1
  • no fire contribution (for example glass, concrete, plaster)
  • RF2
  • low fire contribution (for example oak wood, fire treated materials)
  • RF3
  • permissible fire contribution (for example most other types of wood)
  • RF4
  • non-permissible fire contribution (for example wood chips, cardboard)

This means that you may use materials from fire behavior categories RF1 to RF3 in house building. There are also other classifications according to corrosiveness, smoke development and flaming droplets/particles.

If you want to take a closer look at which building materials fall into which category, you will find a list of all the products approved by the VKF, such as building materials, components and combustion aggregates – plus the names of specialist companies – in the Swiss VKF fire protection register.

Burning behavior of building materials

In addition to their RF classification, building materials are classified into flammability grades 3 to 6 according to their burning behavior. This depends on their ignitability and burning rate. Flammability increases from classification 6 to classification 3. Materials that are particularly highly flammable and burn extremely quickly (flammability grades 1 and 2) are not permitted as building materials and may not be used. Flammability grades 3 to 6 indicate the following burning behavior:

  • Flammability grade
  • Burning behavior
  • Flammability grade 3
  • Building materials that are highly combustible and burn away of their own accord quickly without additional heat input
  • Flammability grade 4
  • Building materials that are combustible to a normal degree and continue to burn independently for a long time without additional heat input
  • Flammability grade 5
  • Building materials that are difficult to ignite and only continue to burn or char slowly with additional heat input. After the heat source has disappeared, the flames must extinguish after a short time and the afterglow must stop
  • Flammability grade 5 (200 °C)
  • Building materials that meet the requirements of flammability grade 5 even at an increased ambient temperature of 200 °C
  • Flammability degree 6q
  • Building materials that have a low proportion of flammable components but are not combustible and are assessed as non-flammable for practical purposes. Specific evidence is required for this assessment
  • Flammability grade 6
  • Building materials without flammable content, which are not combustible and do not char or incinerate

In addition to building materials, entire components (for example supports, walls and doors) are also divided into categories. Their so-called fire resistance duration is abbreviated by the letter R plus a time in minutes. R60, for example, refers to a column that retains its load-bearing capacity for at least 60 minutes in the event of fire. In the same way, the letter E denotes impermeability to smoke and the letter I indicates the insulating capacity of a component – both of which also have a time specification. A component could be marked REI 60-RF1, for example.

Thanks to these three details, you can now identify the fire properties of a building material or component.

Building materials: how to improve fire protection in your single-family house

You may use any approved building materials when constructing a house, including those that are considered “highly flammable”. However, you as a building owner can voluntarily increase the fire protection measures. This means that you can use building materials with increased fire resistance properties for all separating components – such as doors, walls and ceilings – so that the fire cannot spread unchecked in the event of a fire.

Even in kitchens, where the stove poses an increased fire risk, no special fire protection requirements apply. Nevertheless, it is advisable to design the surrounding walls and installations to offer increased fire resistance. Nor are fire extinguishers, sprinkler systems, lightning protection and fire alarm systems required in residential buildings. Here too, you can voluntarily create additional protection for yourself and your family.

In order to ensure optimum fire protection, it is therefore best to clarify the detailed physical properties of the building materials and construction elements with your architect or building contractor in advance.

Further regulations for structural fire protection in single-family houses

The following regulations apply with regard to structural fire protection:

1. Fire protection distances

The required fire protection distances depend on the materials of the outermost layers of the external wall construction. In principle, the distance to the neighboring building increases proportionally to the flammability of the building materials. It amounts to:

  • four meters if both outermost layers are made of RF1 category materials
  • five meters if one of the two outermost layers consists of flammable building materials
  • six meters if both outermost layers are made of flammable building materials

If the neighboring building is higher than eleven meters or if hazardous substances are stored or processed in it, the fire protection distances must also be increased.

In multi-family houses, each apartment is regarded as an individual fire compartment and must be provided with adequate protective measures.

2. Heaters, fireplaces and chimneys

You may install chimneys, tiled fireplaces, storage heaters or Swedish stoves in all rooms, provided that their function is to heat the room in question. If they are placed in kitchens or living rooms however, they must be for decorative or other purposes only. Oil and gas heating systems on the other hand are allowed in all rooms – regardless of their use. Wood chip, pellet or log-wood heaters must be located in a separate room with a fire resistance of at least EI 30. However, this room may also be used for other purposes, for example as a hobby room or laundry room.

A woman is sitting on a brown leather sofa; she is wrapped in a blanket and is holding a cup in her hand. A magnificent fireplace can be seen in the background.

Chimneys, tiled fireplaces, storage heaters or Swedish stoves always represent a potential fire hazard and are therefore only permitted if they are used for heating. They may be installed in kitchens or living rooms for decorative purposes only.

3. Air extraction in the kitchen

The rule here is that the air ducts of extractor hoods must be constructed with materials of category RF1. The extractor hood pipe usually contains a fire damper as a shut-off device. This is to prevent a source of fire from spreading via the ventilation system.

If this type of shut-off device, approved by the VKF, is installed in the extraction air ducts, the ducts behind the shut-off device must be made of at least category RF3 (cr) building materials. The suffix “(cr)” refers to building materials which demonstrate critical behavior due to their smoke development, flaming droplets or high corrosiveness.

If the extracted air is returned to the air treatment system via extraction hoods, a suitable VKF-approved shut-off device must be installed immediately after the extraction hood.

4. Solar energy systems

On flat or pitched roofs, homeowners are allowed to install solar energy systems, i.e. photovoltaic systems and solar collectors for hot water preparation, without additional fire protection measures, if:

  • the outer layer of the solar energy system is non-flammable
  • the roof complies with the applicable fire protection regulations

If solar energy systems are integrated into the roof, the requirements for roofing and external wall constructions apply. Special attention should also be paid to the laying of electrical cables to minimize the risk of fire. Basically, electrical installations must be carried out according to the low voltage installation standard (NIN 2015) SN 411000.

5. Fire protection distances and ancillary buildings

In single-family houses, virtually the entire house forms a single fire compartment. Even if there is an additional self-contained apartment, the building is usually not regarded as a multi-family unit, but remains a single-family house as far as fire protection is concerned.

Within a plot of land, there are no set fire safety distances between ancillary buildings, other buildings and installations. Ancillary buildings are single-story buildings such as vehicle shelters, garages, garden sheds, small animal sheds or small storage buildings.

However, you must maintain a fire protection distance of four meters from buildings on third-party land. Multiple ancillary buildings are exempt from fire protection distances between one another provided that the continuous area does not exceed 150 m². However, if two buildings are connected by an annex, fire compartments must be created.

6. Quality assurance and declaration of fire protection conformity

As a single-family house, your building comes under quality assurance level 1 (QSS). In most cases this implies minimal effort in terms of quality assurance. As a rule, the overall manager of the construction project takes on responsibility as QA fire protection manager.

However, a declaration of conformity is required for all quality assurance levels QSS 1 to QSS 4, i.e. even for single-family houses. The declaration must be signed by the QA fire protection manager before the inhabitants move into the building and submitted to the fire protection authorities and the owners. It confirms to the fire protection authorities and the owners that all the necessary structural fire protection measures have been implemented, that the fire protection installations are functioning properly and that the users have received instructions regarding the operation, maintenance and servicing of the fire protection equipment.

You will find a template for the declaration of conformity here.

Structures, garages and escape routes: only minor regulations

There are no far-reaching requirements for the following aspects:

  • Structures: there are no requirements for the fire resistance of supporting structures. The same applies to basement floors and adjoining self-contained apartments.
  • Escape and emergency routes: there are no requirements for doors, stairs and corridors within a single-family house. Only the maximum length of the escape route to an exit into the open air is specified: 35 meters.
  • Storage areas for motor vehicles: there are no requirements for garages, or “rooms for the parking of motor vehicles” according to the technical terminology, which are located within or attached to the building.

Even though the regulations are quite straightforward compared to those for large buildings, you as a homeowner must still meet all the relevant requirements and consider which additional voluntary measures you wish to take. Contact your architect or building contractor in good time with regard to fire protection – thanks to this overview, you will have a list of topics ready to discuss.

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