For wood construction, fire safety is a hot topic

Author Arto Nummela l Group Portfolio Development Manager May 14, 2019 3:38:00 PM
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Fire-retardant paint improves wood safety in two ways: it slows down the spread of fire and decreases the amount of smoke produced. For best results, fire safety should be taken into account in the planning stage.

With the increased focus on interior air quality issues in older buildings, many municipalities and cities are becoming increasingly aware of the benefits of wood construction. Wood as a material in interior structures and surfaces evens out fluctuations in interior air humidity, so it serves a specific purpose.

According to the more optimistic estimates, wood construction will double in the coming years.

Always use CE-marked wood products

Wood is a viable construction material not only for public buildings such as schools, libraries, and concert halls, but also for apartment buildings. When building with wood, you need to know about the properties of the material and about modern fire retardants that enable wood to be used in construction on a larger scale.

It’s important to ensure that you purchase fire retardant-treated, CE-marked wood from a company with valid certifications. The CE marking on timber treated with fire retardant always applies to both the timber itself and the industrial finishing. It’s possible to apply a fire-retardant coating at the construction site, but this will not necessarily be acceptable to the fire authorities.

Fire protection certification can be obtained for standard materials, which are 12 mm chipboard and 9 mm plywood. If a fire protection product has been tested with these materials, the certification allows it to be used on top of any other thicker wooden material, within a specific density range. The certification can also be obtained for birch panels, but in this case it typically applies to that particular material only. 

Check the fire classification

The effect of a fire-retardant paint or lacquer is based on a chemical reaction: as the paint is subjected to flame, it expands to form an insulating layer to slow down the spread of fire. The wood will burn eventually, but much slower than untreated wood.

The classification for untreated wood is D-s2, indicating a material that contributes to the spread of fire and produce smoke. For buildings with a large population, surface materials must be selected so that people have as much time as possible to vacate the premises in case of fire.

B is the highest possible classification for fire retardant-treated wood material. When treated with fire-retardant paint or lacquer, the fire classification of wood can be upgraded to B-s1, meaning it “contributes to fire in a limited manner and emits as little smoke as possible”. A is the only fire classification higher than this, covering materials such as concrete, glass, steel, and brick.

Take safety into account at the planning stage

Wood is a safe material for construction as long as its inherent properties are taken into account. There is no treatment that makes wood fully non-combustible, but careful planning goes a long way.

In addition to using fire-retardant paints and lacquers, the following should be considered during the planning stage:

  • Fire load-related issues
  • Load-bearing structures and their resistance to fire
  • The spread of fire to adjacent buildings and from one space to the next

The Puuinfo website is a comprehensive resource on fire safety in wood construction. Ask us for help on paints and lacquers that ensure proper fire safety.

Topics: Wood Fire Protection, Wood Construction

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