--- title: Knowledge Hub - Fire retardants for wood – how do they work? description: Are you looking for more information about fire retardants for wood? You’ve come to the right place. Here we talk about how fire-retardant paint works and what it is used for. --- [![logo-tikkurila](https://knowledgehub.tikkurila.com/hs-fs/hubfs/FIN/Logos%20FIN/logo-tikkurila.png?width=100&name=logo-tikkurila.png "logo-tikkurila")](https://tietopankki.tikkurila.fi/suunnittelijoiden-ja-arkkitehtien-tietopankki?hsLang=en) [For architects and designers](https://knowledgehub.tikkurila.com/fire-retardents-for-wood#)   # Fire retardents for wood – how do they work? Are you looking for more information about fire retardants for wood? You’ve come to the right place. Here we talk about how fire-retardant paint works and what it is used for. Let’s get started! #### Contents ![left-img_3](https://knowledgehub.tikkurila.com/hs-fs/hubfs/left-img_3.jpg?width=685&height=545&name=left-img_3.jpg) ## Part 1: Treating wood with fire retardants increases safety **With the rising popularity of wood construction, the fire protection of wooden surfaces becomes increasingly important. There are strict guidelines in place for the fire protection of public spaces that have potentially large gatherings of people. ** With ecological wood construction promoted at all levels of government all the way up to the EU, fire protection, especially fire-retardant paints and lacquers, need to keep evolving with changing demands. Salt-based impregnating products are sensitive to moisture, which has led to the development of fire-protection products based on intumescent technology. Intumescent products expand when subjected to heat, forming a protective layer on the wooden surface. While they don’t stop the fire entirely, they slow its spread and decrease the amount of smoke produced, giving people more time to vacate the premises. The difference is obvious when compared to acrylate paints, for example. ### Fire-retardant paint (Fontefire WF) vs. acrylate paint We arranged a fire test to see how fire-retardant paint compares to acrylate paint. We treated one wooden panel with just acrylate paint and another with both fire-retardant and acrylate paint, then exposed them both to fire. The surface treated with only acrylate paint caught fire, but the surface treated with fire-retardant paint (Fontefire WF) formed a protective film on top of the panel, extinguishing the flames. The intumescent topcoat of the fire-retardant paint forms a porous layer on the panel surface, insulating the wood from the increased heat caused by the fire and inhibiting the flames. This slows down the spread of fire compared to an unprotected wooden surface. ## Waterborne and ecological fire-retardant paint Tikkurila fire-retardant products contain no ingredients that are hazardous to humans. And since they are waterborne, fire-retardant paints cause less emissions and are environmentally friendly and safe to use. They also contain fungicides that protect wooden surfaces against mold, algal growth, and other microbes. The wood therefore doesn’t require any additional impregnating product, saving on costs. And with the surface treatment taking place at the factory under controlled conditions rather than at the construction site, emissions are reduced even further. This also prevents fugitive emissions on site. Properties ![fontefire-wf-logo](https://knowledgehub.tikkurila.com/hubfs/FIN/Kuvat%20Tietopankki%20-%20arkkitehdit%20ja%20suunnittelijat/fontefire-wf-logo.jpg) ![Fontefire-wf-clear](https://knowledgehub.tikkurila.com/hubfs/FIN/Kuvat%20Tietopankki%20-%20arkkitehdit%20ja%20suunnittelijat/Fontefire-wf-clear.jpg) Waterborne ** ** Environmentally friendly ** ** Safe to use ** ** Protects wood from microbes ** ** No separate impregnating products needed ** ** ## Part 2: Fire retardants for wood – how do they work? Fire-retardant paint is based on intumescent technology: as the paint is subjected to heat, the surface expands to form an insulating foam, slowing down the rise in temperature. When treated with a fire retardant, 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. The classification for untreated wood is D-s2, with s2 indicating a material that contributes to the spread of fire and produces smoke. [** ](https://youtu.be/yJVfzTDejlg) ## Watch the video to see how fire-retardant paint reacts to flames. ## Intumescent vs. salt-based fire retardants? In addition to products based on intumescent technology, there are also salt-based products that prevent wood from burning. However, salts are very sensitive to water and are easily depleted from a wooden surface, reducing performance. When using salt-based products, please keep in mind that when painted over with regular paint, the topcoat may emit smoke during a fire. And with salt’s sensitivity to water reducing waterborne topcoat adhesion, regular paint is not recommended as a topcoat for salt-based products. When fire protection is applied correctly, the topcoat paint or lacquer – the surface subjected to abrasion – also meets fire protection standards. This type of comprehensive topcoat system provides the best possible protection against fire. Properties ![intumescent_technology-1](https://knowledgehub.tikkurila.com/hubfs/intumescent_technology-1.jpg) ![salt-based_product-1](https://knowledgehub.tikkurila.com/hubfs/salt-based_product-1.jpg) Slows down the effects of fire ** ** Long-lasting protection ** ** Resistant to water ** ** Topcoat may be waterborne ** ** Reduces smoke formation ** ** Topcoat may increase smoke formation ** ** ## Part 3: How are fire retardants used? Fire-retardant paint can be used for any wooden building, whether residential or public. It is suitable for interior surfaces, facades, and roof structures. Fire retardants are designed for industrial spreading, meaning that they are sprayed on a wooden surface under controlled conditions rather than on-site. This ensures that a sufficient amount of the protective coating ends up on the wooden surface. For smaller areas, you can spread the paint on-site with a roller or brush, but it is essential that the paint layer is sufficiently thick. It’s therefore recommended that the protective coat is sprayed on before taking the lumber to the construction site. ## Topcoat provides protection from abrasion and UV rays A topcoat of paint or lacquer is nearly always applied on top of a fire-retardant layer to protect against wear and UV rays. For surfaces not subjected to wear, such as ceilings, fire protection alone can be sufficient.  In terms of appearance, a fire-retardant coating is no different from any other paint. If you opt for lacquer, the wooden surface is still beautifully visible underneath the lacquer. It is highly important to ensure, however, that the topcoat applied contributes to fire safety and meets regulations. In a fire, the wrong kind of topcoat paint or lacquer can lead to the formation of smoke, meaning that some fire protection properties do not work as they should. ## Ensure proper use of CE markings For fire-retardant products, the CE marking always applies to the timber, not the paint job. It’s therefore important to ensure that wood treated with fire retardant is purchased from a company with valid certifications. Applying fire-retardant coating on top of a non-CE-marked product may not be acceptable to fire authorities. Fire protection certification can be obtained for standard materials, which are 12 mm chipboard and 9 mm plywood. If the fire protection has been tested with these materials, they can be used on top of any other materials. Read more about this topic → ## Part 4: Fire protection products for wood If you’re ready to get started, you can read more about Tikkurila fire protection products for wood below.  The product information is followed by some frequently asked questions. So, if you feel like you need more information, scroll down or contact our experts! ## Fontefire WF Fontefire WF is a waterborne paint with superior fire protection properties for wooden surfaces. When exposed to fire, it forms an insulating layer on top of the wood. The paint meets fire safety requirements for wood construction, and it’s suitable for interior surfaces. [Read more and download the Fontefire WF brochure →](https://new.tikkurila.com/industry/products/fontefire_wf)   ## Fontefire WF Clear Fontefire WF Clear is a waterborne lacquer for protecting interior wooden surfaces that brings out the natural beauty of wood and allows it to be used for interior design in buildings that need to meet the strictest fire safety regulations, such as hospitals and schools. [Read more and download the Fontefire WF Clear brochure →](https://new.tikkurila.com/industry/products/fontefire-wf-clear)   ## Akvilac WF 10 Akvilac WF 10 is a waterborne, chemical-resistant lacquer for interior surfaces. Used in tandem, Akvilac WF 10 and Fontefire WF Clear lacquer provide B-s1, d0 fire protection classification. [Read more and download the Akvilac WF 10 brochure →](https://new.tikkurila.com/industry/products/akvilac_wf_10)   **Below you can find frequently asked questions about fire-retardant paints. If your question is not on the list, get in touch and we’ll add it to the list with an answer.** ## Part 5: Frequently asked questions on fire protection #### Why use fire-retardant products? Fire retardants slow the ignition of wood and the spread of fire, while also creating less smoke than untreated wood. This provides valuable extra time for people to escape and for emergency services to reach them, while reducing the effects of smoke inhalation. #### How do fire retardants work? When exposed to heat, fire-retardant material expands and creates an insulating foam layer on the wood. The porous foam layer insulates the wood from the flames, preventing the wooden surface from heating up rapidly or catching fire. This is known as intumescent technology: fire protection based on the paint surface expanding when exposed to heat. Compared to salt-based fire-retardant products, surfaces treated with intumescent technology can better withstand moisture, UV light, and weather. #### Which wooden surfaces need fire protection? Generally speaking, wood can be used as a construction material without fire-protection treatment. However, depending on the site and the customer requirements, treatment can make the building safer. This extra protection enables a wider use, for example in the following types of buildings: - Schools, kindergartens, and assisted-living facilities - Stores - Detached houses, terraced houses, and apartment buildings - Offices - Hotels - Libraries - Annexes or extra floors with wooden frames #### Can fire retardants be used with all types of wooden surfaces? For less-common types of wooden material, please get in touch with a Tikkurila expert before applying a fire-retardant paint. You can get in touch with an expert here.  #### What types of fire-retardant materials does Tikkurila offer? We currently offer the following products for fire protection: - Fire-retardant paint for interior surfaces (Fontefire WF) - Fire-retardant lacquer for interior wooden surfaces (Fontefire WF Clear); and - Chemical-resistant surface lacquer for fire-protected surfaces that need to withstand cleaning with common household chemicals (Akvilac WF 10). #### Are fire-retardant paints and lacquers environmentally friendly? Yes. Tikkurila’s fire-retardant products are waterborne, which means they produce less emissions and are environmentally friendly and safe to use. #### Tikkurila’s fire-retardant products carry the B-s1, d0 fire safety classification. What does this mean? B-s1, d0 is the best possible fire-safety classification for wooden materials. Construction products and building elements are divided into various fire classifications according to the EN 13501-1 European fire safety standard. The classification also includes an A class, reserved for non-combustible materials such as steel. **Here’s a more detailed listing of the fire classifications for construction materials:** Construction materials are labeled with the following markings, with the exception of flooring; smoke emission and flaming droplets are identified with the extra classifications “s” and “d”. For smoke emissions the classifications are s1, s2, and s3, and for flaming droplets d0, d1, and d2.   A1 = Materials that do not contribute to fire at all (non-combustible materials) A2 = Materials with extremely limited contribution to fire B = Materials with very limited contribution to fire C = Materials with limited contribution to fire D = Materials with acceptable contribution to fire E = Materials with acceptable fire behavior F = Materials with no defined type of fire behavior s1 = Very low smoke emission s2 = Low smoke emission s3 = Smoke emission does not meet s1 or s2 requirements d0 = No flaming droplets or particles d1 = Flaming droplets or particles burn out fast d2 = Production of flaming droplets or particles does not meet d0 or d1 requirements  Source: E1 Suomen rakentamismääräyskokoelma For more information about fire classifications, please see the [Puuinfo technical data sheet on fire classifications for surfaces and roofing materials](https://www.puuinfo.fi/sites/default/files/pintojen-ja-katteiden-paloluokat.pdf). #### What color is Fontefire WF fire-retardant paint? The paint is light gray, adding to the covering properties of the entire paint surface. #### Can a wooden surface be painted first and then the Fontefire WF Clear fire-retardant lacquer applied on top? No. Fontefire WF Clear must be directly applied onto the wood without any priming lacquers in order to meet the requirements of the B-s1, d0 surface classification.  Fontefire WF Clear is transparent white. Tikkurila’s fire-retardant products are intended to be applied directly onto the wood. If surfaces are first painted or tinted the fire-retardant properties will not necessarily work as intended. Additionally, the light surface lacquer will cause light to refract, creating a hue for the underlying surface that is not necessarily what the customer wanted. #### Can Fontefire WF Clear be tinted? No. The fire-retardant classification is only approved for clear lacquer, not tinted. #### Can Akvilac WF 10 surface lacquer be tinted? Not at the moment, though we are currently testing a tinted surface lacquer to investigate how well the fire-protection properties are maintained when tinting. #### Can you paint over Fontefire WF products with any paint? No. The fire-retardant classification is only retained if one of the following products is used as a topcoat: - Ultra Pro, 709 series - Akvi Top DS 25 (interiors) - Akvilac WF 10 (interiors) #### Do fire-retardant products always need to have a topcoat? If a fire-protected surface needs to be abrasion resistant, it should be finished with a top lacquer or paint. Indoors, a fire-retardant lacquer alone is sufficient for wood surfaces that are not subject to wear, such as ceilings. #### How should fire retardants be applied to wooden surfaces? Fontefire WF products are developed, and primarily intended, for industrial painting. In addition to vacuum application, spraying, and curtain coating, the products can be applied onto small surfaces with brushes or rollers. Only industrial paint shops currently hold valid fire-retardant certifications. #### If there is an air gap in the structure, can panels or boards be treated with Fontefire WF Clear fire retardant? No. For special circumstances always consult a local fire protection specialist. [![Tikkurila](https://knowledgehub.tikkurila.com/hs-fs/hubfs/FIN/Tikkurila_February2019%20Files%20FIN/Images/logo.png?width=128&name=logo.png "Tikkurila")](https://www.tikkurila.com) General Links - [Contact us](https://tikkurila.com/contact) - [Privacy Policy](https://tikkurila.com/privacy-policy) - [Terms of Use](https://tikkurila.com/terms-of-use) Technical Service **Metal **phone: +358 20 191 2004 ** Wood** phone: +358 20 191 2005 info.coatings@tikkurila.com - [FACEBOOK](https://www.facebook.com/tikkurilaproservicesuomi/) - [LINKEDIN](https://www.linkedin.com/company/10175738/) - [INSTAGRAM](https://www.instagram.com/tikkurila_suomi/) - [YOUTUBE](https://www.youtube.com/channel/UC77ZpDSvbgQoH3b9VGJlpSg) © 2020 Tikkurila - [Tikkurila.com](http://www.tikkurila.com/), [China](http://www.tikkurila.cn/), [Denmark](http://www.tikkurila.dk/), [Estonia](http://www.tikkurila.ee/), [Finland](http://www.tikkurila.fi/), [Germany](http://www.tikkurila.de/), [Ireland](http://www.tikkurila.ie/), [Kazakhstan](http://www.tikkurila.kz/), [Latvia](http://www.tikkurila.lv/), [Lithuania](http://www.tikkurila.lt/), [Norway](http://www.tikkurila.no/), [Poland](http://www.tikkurila.pl/), [Russian Federation](http://www.tikkurila.ru/), [Sweden](http://www.tikkurila.se/), [United Kingdom](http://www.tikkurila.co.uk/) [www.tikkurila.com](https://www.tikkurila.com)