For many years now, wood has been considered the most popular building material. Its environmental friendliness, ability to breathe and reliably keep heat indoors does not leave indifferent many owners of private property. In addition, such buildings are distinguished by an extremely beautiful appearance and a favorable internal microclimate. But, in addition to the positive aspects, wood has one big drawback - it is fast flammability.
That is why, even at the stage of construction of such structures, it is necessary to use flame retardants for wood, which help to reduce its combustibility and make the building less fire hazard.
What are these means, what types they can be, the principle of action and the criteria for their selection will be considered in our article.
What are flame retardants and how do they work?
Fire retardants are special compounds for the treatment of wooden elements, which in various ways prevent the rapid ignition of such structures. Materials impregnated with these agents are able to withstand the fatal effects of fire for some time and are not amenable to burning. Fire retardants for wood have a fairly low melting point, so their active substances begin to fulfill their protective function even before the wood itself ignites. During melting, the components of the solution emit non-combustible gases, which prevent the ingress of oxygen into the ignition area, so that it does not spread further and begins to decay.
Salt impregnations based on boric and phosphoric acids during heating form a protective film on the wood surface, which prevents the penetration of the flame into the structure of the material.
It should be noted that some combined formulations may be labeled “Antiseptic - flame retardant”. This means that the powder for the preparation of the working solution can be used for two purposes: protection from fire and prevention of colonization by microorganisms.
Types of flame retardants
Protecting wood from fire is carried out using impregnation or coatings.
The latter type includes paints, varnishes and special pastes. It is used much less often, since it has a significant drawback. Coatings completely hide the natural structure of wood, which negatively affects the appearance of the entire structure. For this reason, they are recommended to be used only on hidden surfaces. Fire-resistant impregnations do not paint over beautiful wood reliefs and even emphasize them.
This species is divided into atmospheric and unstable solutions. Unstable (in other words, leachable) products are used in enclosed spaces in which the humidity level does not exceed 70%. Such solutions are characterized by low cost. For processing facades,
wood impregnation is used for outdoor work,
which is endowed with increased resistance to moisture.
Tool selection
When choosing this or that means, it is necessary to know that absolutely all fire-retardant products must have documentation confirming its quality. If the seller cannot show the relevant certificates, you should not make a choice in favor of his product, since most likely it was produced without taking into account the requirements and can be dangerous to humans.
To protect the most important elements (such as beams and supporting structures), wood impregnation is used for outdoor work, which guarantees the maximum degree of protection.
For interior surfaces that perform a decorative function, you can use water-based impregnations, which can be supplemented with various dyes.
In any case, the fire retardant for wood must meet the following requirements:
- not have components that emit harmful substances into the air;
- not violate the natural properties of the tree (environmental friendliness, air exchange, etc.);
- match the application environment.
Positive features of fire retardant procedure
1. High degree of protection of buildings against fire. In the event of a fire, wooden structures may become charred, but will not catch fire.
2. Fire-resistant impregnations have many types, differing in composition, purpose and cost. Therefore, the buyer can choose an option that meets any requirements.
3. The process of applying the product to wood is quite simple, processing can be done with your own hands, without resorting to the costly services of specialists.
The degree of penetration of impregnation into the surface
Fire retardant for wood can be deep or surface penetration.
In the process of household processing, surface impregnations are used. Often, the owners cover the walls of already finished buildings, so deep impregnation is impossible. The cost of surface solutions is low, so the protective characteristics are also low. The solution is applied with a brush, roller or spray.
Deep processing is carried out by soaking the beam in special containers, after which the material is carefully dried and already used for the construction of buildings. Such protection is considered the most reliable.
Of course, it is possible to use deeply penetrating flame retardants for wood and for surface application, but in this case the degree of their absorption in the wood structure will be much less than during soaking.
Useful flame retardant treatment tips
Whatever fire retardant is chosen for wood impregnation, the reliability of protection depends on strict observance of the rules for its application. So, treatment with saline solutions should be carried out exclusively in warm weather, at an air temperature of 5 to 25 degrees and low humidity. Contact with metal elements should be avoided, since an increased salt content can cause corrosion.
Fire retardants for wood-based wood should not be used to impregnate old and dry wood, as it absorbs moisture and swells.
Non-salt impregnation can be used in the temperature range from - 15 to + 40 degrees. These species penetrate the structure of the material as quickly as possible, but are toxic. Based on this, these funds can only be used for outdoor work.
The surface to be treated must be sufficiently dry and not coated with paints, varnishes and other compounds. Pre-heating the wood allows you to increase the penetration depth of the protective agent from 3-4 mm to 5-8 mm.
Protective paints
As mentioned earlier, wood protection can be carried out using wear-resistant facade varnishes and paints. Such coatings are divided into 2 categories: intumescent and non-intumescent.
The first group is different in that when the temperature rises, the material begins to crack, moisture and inert gas are released, as a result of which the fire does not spread to the wood.
Means of the second group include fire-fighting fillers and liquid glass. Such coatings can withstand fire for 100 minutes.
With the help of paints and varnishes, protection against mold, rot and colonization by microorganisms is carried out.
Consumption of funds and its life
Saline solutions are very poorly fixed on a wooden surface, therefore, in order to achieve the maximum degree of protection, it is necessary to use at least 400 grams of the product for each square meter of the surface.
Due to poor fixation, the impregnation does not penetrate deep into the wood and is quickly washed out. For this reason, re-treatment should be carried out no later than 2 years.
Non-salt impregnations penetrate the structure of the tree very easily, so much less solution is required for impregnation. About 1 gram should be used on 1 m 2 . The service life of such protection is 5 years for external use and 15 years for internal use.
The frequency of coating with paints and varnishes is 6-7 years.
During the operation of wooden surfaces, it is necessary to regularly inspect their condition. If chips appear, protective coatings fall off, or the impregnation is washed off by more than 70%, re-treatment should be carried out as soon as possible.
How to check the quality of flame retardant
In order to be sure of the fire safety of the treated structure, you can conduct a test on the quality of the purchased product.
To do this, a small piece of wood is impregnated in the existing solution and allowed to dry well. The sample is then set on fire and the chemical reaction taking place is monitored. If a quality solution was used for processing, the piece will not burn and smolder. After 0.5 minutes the surface of the bar may become charred, darken, but in no case catch fire!
If the flame did not appear, the impregnation was made in accordance with the requirements and can be used for further processing of the building.
In conclusion, we note that the timely processing of materials and walls made of wood helps several times reduce the possibility of a fire and even save a life. Therefore, do not save on your own safety and health of all family members. Use the products of well-known and well-established brands that guarantee the excellent quality of their funds.