Liquid for wood treatment from burning. How to ensure maximum protection of wood from fire? By impregnation with protective agents of wood species

It is difficult to overestimate the importance of wood as a building material. Noble appearance, ease of processing, creation of a favorable microclimate in the room, high thermal insulation properties- this is an incomplete list of all the advantages of wood products. But there are also some "pitfalls". Wood, unlike metal or concrete, can easily ignite, be affected by fungi, rot, and turn into a habitat for insect pests. In order to eliminate these shortcomings, there are special methods of wood processing, which we will talk about now.

Protection of wood from fire can be carried out by applying flame retardants or impregnation with flame retardants.

fire protective compounds, applied to the surface of wood, protect it from direct contact with fire and do not allow oxygen to penetrate inside, which is necessary for combustion. Among such products, one can single out OFP-9 phosphate coating, VP-9 intumescent coating, NULLIFIRE wood flame retardant, AK-151 KROZ and PPL paints.

Impregnation with flame retardants produces a slightly different effect. These compounds, when exposed to fire, either melt and cover the wood fibers with a fire-retardant film, or decompose and emit non-combustible gases that push out combustible oxygen. Regardless of the time of exposure to fire on wood impregnated with flame retardants, only its charring occurs, and not independent combustion. Popular flame retardants are: borax, ammonium chloride, ammonium sulphate.

Protection of wood from rotting and exposure to fungal microorganisms

Wood-staining, moldy, wood-destroying fungal microorganisms often settle in wood fibers and affect them. Moldy and wood-staining fungi form on the surface various stains and raids, however, do not affect the internal structure. Wood-destroying mushrooms are another matter. As the name implies, these organisms destroy the cells of the tree, using them as nutrients. Externally, such exposure to fungi leads to rotting of wood.

It is important that fungal infection is possible only in certain conditions. As a rule, the impetus for decay is high humidity (50-100%) and heat.

Compositions designed to fight fungal microorganisms are called antiseptics, which are available in the form of coatings and impregnations. The coatings form a film on the surface of the wood, which is a barrier to moisture - the main cause of the appearance of fungal colonies. In addition, many antiseptic coatings contain metal oxides that protect against ultraviolet rays.

Protecting wood from decay - painting iron vitriol

Antiseptic impregnations penetrate the wood to a depth of about 1 cm and produce an antimicrobial and antifungal effect. These compounds, unlike coatings, do not protect against moisture, they specifically fight against microbes and fungi that provoke decay. There are antiseptic impregnations that allow you to eliminate an already existing problem, for example, the drug "Wood Doctor". This composition is available in three modifications: DR-1 - to prevent decay, DR-2 - to destroy colonies of microorganisms that have already appeared, DR-3 - to stop the process of decay and repel insects.

Unprotected wood absorbs water like a sponge, and this will almost certainly cause it to rot. The most popular way to protect wooden structures from the water is their cover paintwork materials. However, paints, during the operation of a wooden product, often burst, water penetrates into microcracks and the wood can rot. To prevent this from happening, it is recommended to apply a layer of antiseptic coating on the product before painting. Such wood protection will be the most effective.

We protect our fence from moisture

Protecting wood from insects

Insects can cause irreparable damage to wooden structures, turning them into dust. Termites, ants, wasps, beetles infect wood, while the main sign of their appearance is the holes from which adults fly out.

As protection against wood-destroying insects, insecticide substances are used: oil antiseptics, DDT, chlorophos, chlorodan, chloropicrin, etc.

In addition to preparations of local action, there are complex compositions that allow you to protect wood in several directions at once. For example, the KSD preparation is quite well-known, which is both a fire retardant and an antiseptic, and the other composition of DR-3 mentioned earlier allows you to forget about fungal infections and insect raids.

K category: Wooden structures

Protecting wood from fire

The design measures are rational planning premises and choice optimal parameters structures. For example, the number of floors and the area of ​​buildings with timber structures are limited. Special fire walls (firewalls) should divide buildings into separate rooms. It is recommended to divide air gaps in coating structures into compartments by diaphragms made of asbestos-cement sheets and other non-combustible materials to reduce air leakage in case of fire. At furnace heating(for example, in teams wooden buildings) it is necessary to provide cuttings between the chimney and wooden structures.

Structural measures are supplemented by plastering or nailing thin sheets of asbestos cement. It is also practiced to stick on the construction of aluminum light and heat-reflecting foil or non-combustible polymer films.

Surface plastering and wood veneer asbestos-cement sheets- one of the reliable ways to obtain slow-burning structures. In particular, the coating with sheets in terms of fire-retardant effect is not inferior to cement plaster.

Chemical means of protection are various coatings, fire-resistant paints and impregnating compositions based on low and high molecular weight compounds. Coatings are intended for wooden structures protected from direct atmospheric action. They are prepared at the workplace and applied with a brush in two steps with an interval of 12 hours. 1.2-1.5 kg of flame retardant is consumed per 1 mg of the treated surface. Coatings cover wooden structures that do not require painting (rafters, girders, etc.).

Fire protection chemicals for wood include various formulations, soluble in water, for deep and surface impregnation; painting compositions; polymer modifiers. For deep impregnation of wood, compositions are recommended, including (% by weight, except for water): diammonium phosphate - 7.5, ammonium sulfate - 7.5, sodium fluoride - 2 (MS composition 1: 1); diammonium phosphate - 6, ammonium sulfate - 14, sodium fluoride - 1.5 (MS composition 3:7). Water for dissolution is taken in the amount of 83 and 78.5% by weight. Wood impregnated with these compositions with the absorption of pure flame retardant 50-66 kg/m3, refers to slow-burning materials.

Compositions MC 1:1 and MC 3:7, having a high flame retardant effect, also exhibit the properties of antiseptics. These and similar compositions are called fire bioprotective. Impregnation with compositions MS 1:1 and MS 3:7 does not change the color of wood, but reduces its strength: in compression, chipping along the fibers, transverse bending - by 10%, in impact bending - by 40%. Contact of impregnated wood with metal can cause it to corrode. The compositions are easily washed out of the wood; therefore, they are recommended for protecting structures operated in an environment with a relative humidity of not more than 80%, as well as in conditions that exclude contact of wood with water.

Another preparation for deep impregnation BB-11 contains (% by mass): technical borax - 10, boric acid - 10, water - 80. The preparation is used for fire protection of wood when absorbing dry salt at least 50 kg/m3; penetrates well into the wood, does not change its color, does not interfere with gluing and scraping; increases the strength of wood for compression along the fibers and transverse bending, but reduces the resistance to impact bending; has antiseptic properties; safe for people and animals; allows contact of impregnated wood with metal. To prevent the influence of condensation moisture, wood impregnated with water-soluble compounds is recommended to be additionally painted.

A fire-bioprotective preparation XMHA has been developed, which includes a directional component: sodium bichromate, copper sulfate and ammonium chloride in a ratio of 1:1:2 to 1:1:12.

The drug is highly effective as a fire retardant and is sufficiently resistant to leaching. The MB-1 preparation has a fire-retardant effect, including (% by mass): copper sulfate - 2.7, borax - 3.6, ammonium carbonate - 5.3, boric acid - 3.4, water - 85. Its consumption during impregnation 60 kg/m3 solids. Colors wood light green.

Many inorganic and organic compounds phosphorus. For the impregnation of wood, a TCEP preparation is proposed, consisting of trichloroethyl phosphate dissolved in carbon tetrachloride in a ratio of 2:3. With deep impregnation, the consumption of this fire retardant is 60 kg/m3. The color of wood does not change, strength does not decrease, and corrosion of metals does not occur.

Compositions for deep impregnation prevent self-burning of wood, reduce the spread of fire from external sources, increase the fire resistance limit (for elements with a cross section of 120 × 120 mm - by 5 minutes), transfer wood to a group of fire-retardant materials.

When preparing solutions, their concentration is controlled by a hydrometer and compared in density with reference solutions (at 20°C). The distribution of salts by volume of impregnated elements is controlled by mass increment and by chemical indicators. For ammonium salts, the indicator is a 4% solution of basic benzidine in 15% acetic acid, causing darkening of well-soaked places. For boron compounds, the indicator is a solution of curcumin.

The amount of the injected solution is determined by the control impregnation of wood by increasing the mass of the element. Usually, the weight of blanks increases by 50-70%, which corresponds to the absorption of dry salts up to 75 kg/m3. The parts impregnated with the solution are dried at a temperature not exceeding +70°C (to prevent the decomposition of salts). In this case, the blanks are positioned so that they do not come into contact with the metal parts of the drying chamber. Drying ends when wood moisture reaches 10-12%.

Fire protection of glued products. Wood fire-retarded with salts is in many cases suitable for the manufacture of glued products. However, the adhesion strength is adversely affected by the salt concentrates contained on the surface of the element. To improve the bonding conditions, this concentrate is washed off with warm water, then the surface is dried. The amount of salt on the surface is also regulated by washing it off with distilled water heated to 70°C. It is not directly related to the amount of salt contained in the volume of wood.

For glued wooden structures, surface impregnation with flame retardants is more often more profitable. It makes it difficult for the flame to spread over the surface, facilitates extinguishing a fire, and in some cases excludes the possibility of its occurrence. The main components of compositions for surface impregnation are diammonium phosphate, ammonium sulfate (MS composition) or potassium carbonate (PP composition). Their content in aqueous solution is 25% by weight. For better wetting of the surface, kerosene contact or nekal is added - 3% by weight.

The composition of MS is easily washed out of wood, therefore it is not recommended for the protection of structures that are wet during operation or are in air with a relative humidity above 80%. The composition does not cause corrosion of metals, but worsens the conditions for gluing and painting impregnated wood. The composition of PP, as well as MS, is easily washed out, but does not interfere with the staining of wood. Unlike the MS composition, the PP composition does not possess bioprotective properties. Without additional moisture protection, wood impregnated with PP composition can only be used in dry rooms.

Fire retardant paints. Organosilicate, perchlorovinyl, phosphate, organosilicon paints are used. According to operational characteristics, they are divided into weather-resistant, suitable for outdoor use and waterproof, used for wood processing in indoor structures. When applying paints on structures, the moisture content of wood should not exceed 20%, and the air temperature should not be less than 10°C. Paints are applied with a brush or spray gun.

OS organosilicate paints are suspensions of activated silicate and oxide components in toluene solutions of modified polyorganosiloxanes. Supplied by the manufacturer complete with a hardener - polybutyl titanate. Apply at normal and low temperatures on a dry surface of wood, forming a matte opaque coating with a thickness of at least 250 microns. The coating has low water permeability and thermal conductivity, significant thermal and frost resistance; withstands sudden temperature changes from -60 to +600 ° C, but has a low mechanical strength and weak adhesion to wood; has a waterproof effect. Wood coated with OS paints belongs to the category of flame-retardant materials.

Perchlorovinyl enamel ХВ-5169 is recommended for fire protection of wooden structures operated outdoors. Enamel is produced ready-made, dries quickly, is applied to the surface in several steps with a total consumption of 0.6 kg/m2, has a strong adhesion to wood. The coating is very elastic and crack-resistant, has good moisture-proof properties; transfers wood to the category of hardly flammable materials.

You can combine surface impregnation with staining. The impregnating composition of PP is applied with a brush or spray gun twice, then the wood is dried. Next, a perchlorovinyl lacquer plasticized with sovol is applied. The varnish is a solution of perchlorovinyl resin in P-4 solvent (a mixture of butyl acetate, acetone and toluene). The varnish is applied in several layers with a break of 3 hours. The combination of surface impregnation with polymer coated stabilizes the protective effect of the impregnating composition and preserves decorative qualities wood. After applying the impregnating and protective compositions, the wood becomes difficult to ignite.

There are several paint compositions based on powdered, water-soluble carbamide resins or based on urea combined in the paint with formalin for the resin formation reaction. The presence in these compositions of monoammonium phosphate and dicyandiamide, which decompose when high temperature with the release of gases, allows you to get intumescent paints with a high fire retardant effect. IFC paint is prepared by mixing two parts - liquid and dry in water. The liquid part includes formalin, neutralized with 10% sodium hydroxide to pH = 7, and urea and dicyandiamide dissolved in it. The dry part includes monoammonium phosphate with additives. The ratio of dry, liquid and water is 5:2:1.6. The liquid part is first diluted with water, and then poured into the powder with stirring. The paint is intended for coating wooden structures used in heated rooms.

It is applied in two layers on the cleaned surface with a total consumption of 0.6 kg / m2 (the second layer - after 72 hours) at a positive (not lower than 10 ° C) temperature and relative humidity air no more than 90%. The paint forms a coating white color.

An active intumescent property is a paint consisting of a water-dilutable powder mixture comprising (% by weight): urea-formaldehyde resin 50.5; monoammonium phosphate 15; dicyandiamide 15; aminocaproic acid (filler) 7.5; nekal (wetting agent) 2. Before use, the mixture is diluted with water to a painting consistency. The composition is applied in two layers with a total consumption of 0.5 kg/m2.

Intumescent coating VPM-2D is a mixture of heat-resistant and gas-forming fillers in an aqueous solution of polymer binders. The coating is non-flammable, non-toxic and non-moisture resistant. Transfers wood to the group of slow-burning materials at a raw mixture consumption of about 0.7 kg / m2. It is recommended for use indoors at a relative air humidity not exceeding 80% and a temperature not exceeding 50 °C.

The use of phosphate fire-retardant coatings is promising. These are compositions that harden as a result of reactions of various inorganic compounds with phosphoric acid or its derivatives. The intumescent coating OFP-9 contains a phosphate binder - sodium hexametaphosphate and fillers. The fire-retardant effect of the coating is based on the thermal decomposition of a mixture of urea and aluminum hydroxide. The gaseous substances released during heating swell the softened coating film, creating a heat-insulating screen. The coating is applied to dry wood with a consumption of 0.4 kg/m2 of dry mass, hardens within 3-6 hours. OFP-9 coating is not moisture resistant. The wood covered with it belongs to the category of slow-burning materials.

Combined compositions are used for fire retardant wood, for example, a mixture of liquid glass (40-45% by weight), urea-formaldehyde resin (40-45%), sodium chloride (10-20%). The flame retardant is applied with a brush or spray gun in two layers with a break of 1 hour. Its consumption is 350-500 g/m2. Another composition includes (% by weight): unhydrated mica 12-38.4; urea-formaldehyde resin 25-35.6; water 40-52; ammonium chloride 0.2-0.4. Mica should have a thickness of 0.01 mm with a nominal flake diameter of 0.15-2 mm. Combined compositions are recommended for fire protection of fabric structural elements, chipboard and wood-fiber boards.

Wood is a soft, but durable, favorite material for building houses in summer cottages. Even if the building is built of brick or foam blocks, logs, timber or boards are used to build a bathhouse, garage, gazebo, veranda. Can't do without wooden decor- wells, benches, swings, bridges. Fences and fences are also made of wood. To avoid the rapid destruction of the material, it is necessary effective protection wood from external factors: excessive moisture, fire, insect pests.

If the moisture content of the material exceeds 15%, the structure of the wood begins to collapse: swell, delaminate, and then shrink. As a result, the products change their shape, cracks and gaps appear. Almost all wooden elements are affected by high humidity, except, perhaps, sisal and rattan, as they come from the tropics.

The experiment showed that water does not penetrate into the pores of a bar treated with a water-repellent composition, while it is quickly absorbed into unprotected wood.

Exist special solutions, with the help of which the wood is protected from moisture. They are divided into two groups:

• penetrating;
• film-forming.

The first group provides a more reliable barrier against the penetration of liquid into the wood structure. The process of processing with the compositions of the second group must be repeated over time. Consider two means of resisting high humidity.

Aidol Langzeit-Lasur is a medium-viscosity impregnating compound, excellent for covering the walls of a house, country furniture, balcony and terrace railings, fences. Azure is safe enough to cover children's toys and buildings. It has many decorative shades: silver gray, teak, ebony, dark oak.

If wood is treated with Aidol Langzeit-Lasur impregnation conifers, it should be primed first. This rule also applies to products damaged by fungus or mold.

Belinka Interier Sauna includes acrylic resins, water and additives. This is a colorless azure, ideal for processing wood in baths or saunas. Two coats of the solution are applied with a roller, brush or sprayer.

Belinka Interier Sauna does not mask the natural texture of wood, but only makes it more silky and shiny. A can of azure 2.5 liters costs 950-1000 rubles

Ways to protect against decay

Changes in temperature, precipitation, solar radiation lead to untimely decay of wood. The first signs of decay are the appearance of mold and fungus. Large areas of foci indicate that the material can no longer be saved. If wooden products or buildings experience atmospheric troubles, high humidity from precipitation and condensation, it will not be superfluous to carry out preventive work that will protect the wood from decay.

The best helpers in this matter are antiseptics, which are pastes or liquid solutions. Some of them are universal, that is, they protect the material not only from moldy fungi, but also from beetles. Examples of such formulations are two popular remedies.

PINOTEX IMPRA is used to treat wooden surfaces that are not subject to further decoration. Usually these are beams, roof slings, lathing details, that is, hidden parts of buildings. Impregnation has a green color. On the wood covered with it, the appearance of mold, blue, fungus and rot is excluded.

The antiseptic Pinotex Impra goes on sale in large containers. Means price: 3 l - 1100 rubles, 10 l - 3350 rubles

Senezh Ecobio is used both as an independent coating and as a primer for varnish or paint. 2-3 layers of the product protect the wood from decay for 30 years.

If the wooden surface was originally treated with varnish, paint, drying oil or other water-repellent agents, it is useless to use SENEGE ECOBIO

Flame retardants - reliable fire protection

To protect wood from fire, there are fire-resistant solutions - flame retardants. For residential buildings, they are mandatory. Under the influence of a flame, the substance with which the wood is impregnated turns into thin film capable of blocking the flame for some time. Coatings are of different types:

• solutions;
• plasters;
• paints;
• coatings.

Flame retardant sample - NEOMID 530, impregnation for exterior and internal works. Guaranteed service life - 7 years. Reliably protects wooden walls, ceilings, door and window blocks, partitions. The composition of the flame retardant does not change the structure of the wood. Lacquers, paints, primers can be applied over the fire retardant solution.

It should be borne in mind that when applying the flame retardant NEOMID 530, a slight tinting of the material occurs, depending on the type of wood, so it is recommended to test it before starting work.

Pyrilax is a biopyrene that protects wood from fire and localizes fires. The prefix bio- means that the agent is at the same time a barrier to the appearance of mold and insects. The solution provides effective protection inside and outside the building, safe for the treatment of buildings for poultry and livestock.

Pyrilax for external use is not washed out by precipitation for 13-15 years. Indoors, it provides protection for 25 years

Insects - no chance!

Tiny beetles are able to turn wooden furniture, walls and ceilings of the house into dust. Grinder beetles, barbels and weevils, together with their larvae, slowly but surely destroy the untreated construction material. Only protection of wood from harmful insects will save the situation.

It is much easier and cheaper to take preventive measures than to replace damaged logs and beams. Insecticidal solutions will expel already settled pests from shelters and block the way for newcomers. You can use folk remedies - a solution of tar in turpentine, chlorophos, paraffin, or a mixture of kerosene and carbolic acid. But compositions for professional processing are more effective.

Boron Aqua Lacquer impregnates the surface of the wood, protecting it from any negative manifestations from the outside, including beetles. They cover window and door blocks, plinths, stairs, railings, fences, wooden walls of houses. Transparent impregnation does not distort the texture of wood, only changes its color to the desired one. The varnish can be diluted with water, but its percentage should not exceed 10%.

The number of layers of applied Aqua-lacquer depends on the location wooden elements: indoors two are enough, outside - at least three

Tonotex antiseptic serves both to protect wooden surfaces and to decorate. Its composition emphasizes the texture of wood without changing its properties. The range of various shades allows you to give ordinary wood the color of one of the valuable wood species.

Tonotex refers to the universal compositions that are used for processing wood on the territory of a summer cottage: it will protect both from atmospheric troubles and from biological threats

Comprehensive protection of residential buildings

If we compare country house, built in the middle of the last century, and a modern country cottage, you can notice a big difference. It concerns the appearance of wood. Old houses had practically no additional protection, so after a few years the logs became porous, gray, covered with cracks and small holes. Now, thanks to the complex processing of all wooden parts and structures, the appearance of houses does not change over time.

Construction supermarkets offer a large assortment protective compositions for wood: both affordable domestic and more expensive foreign-made

Various impregnations, solutions, azures, varnishes and paints contain substances that protect wood from insects, rapid wear and decay. Using protective compounds in the construction of a house, you can make it really impregnable, reliable and safe.

Wood is a building material that has stood the test of time. It occupies one of the leading positions in the building materials market and serves not only for the construction of buildings, but also for decorative cladding buildings and. The main disadvantage of wood is a weak immunity to decay, insect damage, fire and other negative phenomena, which is why it is very often inferior to its main competitors: metal, stone and plastic. In order to extend the life of wood, it must be treated with protective antiseptics, which we will talk about now.

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How to protect wood from decay?

Because wood is natural material, which is a breeding ground for such moisture-loving ill-wishers as mold and fungus, it is often exposed to the negative action of these bacteria, as a result of which the entire building or wood product rots and collapses.

In order to protect wood from decay, it is necessary to carry out some measures in advance, the main of which are:

• Wood treatment with antiseptics, which are sold in solutions and pastes in any hardware store. It is recommended to apply antiseptics not only on the surface of the tree, but also on the soil in which it is located (the approximate depth of impregnation is 1.5 meters). It is recommended to use a 5% solution of potassium bichromate in 5% sulfuric acid. Popular ready-made antiseptics are products such as: Novotex, Pinotex, Biocron, Biosept.

• Natural and artificial drying of wood. In order to dry the tree naturally, it is necessary to place the material under a canopy or in a well-ventilated room for a period of a week to several months (depending on the climate and the properties of the tree variety). The advantage of this option is that it does not cost money. As for artificial drying, it is carried out either by drying in a liquid medium (tanks with petrolatum) or by storage in chambers with elevated temperatures (exposure to steam or warm air). The advantage of artificial drying is the speed of the process (from an hour to several days) and the defeat of fungal diseases.
• The correct location of wooden structures. To do this, constructive measures are used, such as: the use of a waterproof roof, active ventilation, a high foundation, waterproofing wooden walls etc.

Methods for protecting wood from insects

The main insect pests of wood are the weevil, the barbel beetle and the grinder beetle. They are able to turn wooden buildings and furniture into a pile of dust in a short period of time. In order to determine the action of insects, it is enough to look at the surface of the wood well - if you see small grooves on the walls, holes and piles of dust, then the pests already live in this place.

To protect wood from insects, it is necessary to use antiseptics and insecticides sold in specialized stores. The simplest option protective agent at home - a solution of table salt. Its advantage is harmlessness to humans, the disadvantage is easy rinsing with rainwater. In general, there are many folk remedies protecting wood from insects, popular are:

• Use of tar in turpentine
• Paraffin or melted wax treatment
• Treatment with carbolic solution
• Use of dichlorvos (chlorophos)

You can also use a solution of sodium silicofluoride, which is easily applied to the wood surface with a sprayer or brush.

Effective protection of wood from moisture

In order to simultaneously protect the surface of the wood from damage by insects and fungal infections, it is necessary to use a water-repellent impregnation.

The simplest option water-repellent impregnation- butter. It must be applied to the wood, over the entire surface, so that the oil gets into all the cracks, joints and pores.

It should be borne in mind that applying oil to the surface changes the color of the building or woodwork, making it a little darker.

In addition to applying oil, you can also use popular methods such as tinting and varnishing.

Wood tinting is a process of slight coloring wooden surface using oil paint, alcohol stain, tinted varnish, etc. Wood tinting should be done every 2 years.

Varnishing of wood is carried out in places with high humidity(for example, in baths). For this, water-repellent varnishes are used, which must be applied to the surface of the tree every 5 years.

Protecting the surface of wood from fire

Often, the use of flame retardants is carried out in in public places, such as hotels, restaurants, bars, saunas, etc., but caring owners use means to protect wood from fire and in private areas country houses and suburban areas.

Methods for protecting wood from accidental fire are divided into simple processing salt solutions and treatment with special substances that form protective film on a wooden building.

In the first case, a salt solution is applied to the surface of the wood, penetrating deep into the material, and during ignition, these substances melt, forming a protective film that stops the spread of the flame. Although the fire will stop, the charred wood will need to be replaced.

Treatment with special substances stops the fire in the same way, only much more effectively. For this method, flame retardants are used, which include sulfuric acid, ammonium phosphate and borax. It is also recommended to use plaster, plaster and silicate-based paint.

In order to wooden building served as many years as possible and all this time looked attractive, it is necessary to carry out as often as possible preventive methods wood protection. In order for the protection to be more effective, the tree should be processed before the construction of the structure, in order to allow the material to dry well on all sides.

You should also adhere to the basic requirements before processing wood:

• Do not process frozen wood
• If the surface was previously covered with paint or varnish, it is necessary to carefully process the wood - sand it or sand it off so that the surface has a uniform absorbency.
• The optimum temperature at which processing can be carried out is +20 +25°C. It is allowed to process the material in the range from +10 to +40°C, but in no case below +5°C.
• The wood surface to be treated must be clean and dry.

Video lesson effective wood protection

Drying wood

Drying wood- one of the main measures that prevent the decline in the quality of wood (prevents decay, increases strength, reduces density and tendency to change shape and size).

natural drying carried out in the open air, under sheds or indoors to an air-dry state, i.e., to a humidity of 15 ... 20%. Atmospheric drying is a long (several weeks or even months) and difficult to control process, but it is simple and does not require the cost of heating the coolant.

Fig.1. Atmospheric drying

artificial drying produced in drying chambers electric field high frequency, in hot liquid media and by contact. It can be carried out at any time of the year to any final humidity and in a short time (several days or even hours). This provides high quality dried wood due to the complete controllability of the process and the possibility of wood damage by fungal infection and insects is excluded.

Fig.2. Drying kilns for wood drying

Chamber drying is carried out in dryers of periodic and continuous action. As a heat carrier, heated air, steam, flue gases are used.

Drying in a high frequency electric field due to the heating of wood placed between grid electrodes, to which a high-frequency current is applied. Since the wood surface has more low temperature due to the evaporation of moisture, the water in the wood intensively moves from the inside of the material to the outside. This makes it possible to dry the wood very quickly (10 ... 20 times faster than with chamber drying). This type of drying requires a lot of electricity and is more expensive than chamber drying, so it is used for drying high-quality wood.

Drying in heated liquid media, in particular in petrolatum, was proposed by AI Folomin.

Petrolatum- Waste obtained during the dewaxing of petroleum oils does not dissolve in water and does not mix. When heated to 130...140°C, petrolatum turns into a mobile liquid, into which the dried wood is immersed. The moisture in the wood turns into steam and is removed. In petrolatum, wood dries several times faster (several hours) than in drying chambers, and the material does not crack or warp. The disadvantage of this drying method is the high consumption of petrolatum and its contamination of wood. In terms of cost, this method is approximately equivalent to chamber drying.

Contact drying is used for drying thin wood assortments (for example, veneer, plywood). It is carried out between periodically closing hot plates of the press or on roller installations.

Protection of wood from rotting, insect damage and fire

Protection of wood from rotting and destruction by insects.

To prevent wood decay, a number of constructive measures are taken, the purpose of which is to protect it from moisture (wood is isolated from soil, stone and concrete, ventilation channels are made, protected from precipitation, etc.). When constructive measures cannot completely protect the wood from moisture, it is impregnated with antiseptics - chemicals, which kill fungi or create an environment in which their vital activity becomes impossible.

Antiseptics must have high toxicity (poisonousness) in relation to wood-destroying fungi, but be harmless to humans and animals; maintain high toxicity for a given period; easily penetrate the wood without degrading it physical and mechanical properties and without causing corrosion. metal fasteners; not have bad smell; be resistant at elevated temperatures and during wood processing. They should be relatively cheap and not in short supply.

Water-soluble, organic-soluble and oily antiseptics, as well as antiseptic pastes are used for wood preservatives.

Water-soluble antiseptics used for processing wood, which during operation is protected from direct moisture and the washing out of water.

Sodium fluoride NaF is a white powder, odorless. Used in solutions of 3 ... 4% concentration for antiseptic wooden elements, as well as materials and products made of wood shavings, sawdust, reeds. In contact with lime, cement and gypsum materials, sodium fluoride loses its swap poisonous properties, turning into insoluble calcium fluoride.

Sodium silicon fluoride Na 2 SiFe is a white or gray powder, similar in action to sodium fluoride. Used in conjunction with soda ash, sodium fluoride and in silicate pastes.

Ammonium silicofluoride (NH 4) 2SiFs - an easily soluble white powder, odorless, surpasses sodium fluoride in toxicity, increases the fire resistance of wood, but causes slight corrosion of the metal.

HTC preparations(a mixture of zinc chloride and sodium or potassium chromium peak) and MCC (a mixture of zinc chloride, chromium peak and blue vitriol) are difficult to wash out with water, but they color the wood yellow-green and cause corrosion of ferrous metals, and at high concentrations they somewhat reduce the strength of the wood.

Preparation GR-48 - an antiseptic based on pentachlorophenol, odorless, soluble in water. It is used in a solution of 1 ... 1.5% concentration for surface protection of lumber, in particular from blue and mold.

Organic-soluble preparations of the PL type (solutions of pentachlorophenol in light petroleum products) and the NML type (solutions of copper naphthenate in light petroleum products ) are highly toxic antiseptics that penetrate wood well. Preparations of the second type stain the wood green and make it difficult to glue it. Green oil, fuel oil, kerosene and solvent naphtha are used as solvents. PL preparations are also used to enhance the toxicity of oily antiseptics.

From oily antiseptics the most widely used oils are coal (creosote and anthracene) and shale. Both of these products are dark brown liquids with a pungent odor and strong antiseptic properties. They are not leached with water, the metal does not corrode, but they stain the wood in a dark brown color. The main purpose is deep impregnation of wooden elements located in the open air, in the ground or in water (sleepers, parts of bridges, piles, underwater structures, etc.).

Antiseptic pastes prepared from a water-soluble antiseptic (sodium fluoride or silicofluoride), a binder (bitumen, clay, liquid glass, etc.) and a filler (most often peat powder). Antiseptic pastes protect elements made of wood with an initial moisture content of at least 40% and elements that are moistened during operation (ends of beams, poles, etc.). Elements of open structures treated with paste protect waterproofing coating. Dissolving in water, the antiseptic, which is part of the paste, penetrates into the wood and protects it from decay.

Impregnation of wood with antiseptics carried out by surface treatment, in hot-cold baths and under pressure.

At surface treatment an antiseptic solution is applied to the wood surface with brushes or a spray gun for 2-3 times. Sometimes they practice immersing dry wood in a bath with an antiseptic solution, which allows it to be soaked a little deeper.

Impregnation of wood according to the method of hot-cold baths has the greatest effect. Wood or a structure made of it is first immersed in a hot antiseptic solution with a temperature of 90 ... 95 ° C. At the same time, the air in the pores and vessels of the wood is heated, expanded and partially removed. Then the wood is transferred to a bath with a cold solution or a hot solution is pumped out, and a cold solution with a temperature of 20 ... 30 ° C is fed into the bath. In a bath with a cold solution, the volume of air remaining in the wood decreases, as a result of which a rarefaction is created inside the wood, due to which the antiseptic is absorbed.

Pressure impregnation carried out in special hermetic cylinders-autoclaves. First, a vacuum is created in the autoclave, due to which air is removed from the wood. Then the autoclave is filled with a heated antiseptic and the liquid pressure is adjusted to 0.6 ... 1.5 MPa. The creation of a vacuum and then liquid pressure provides the fastest and deepest, often continuous impregnation of wood.

The main way to deal with wood-destroying insects in timber warehouses is to maintain the warehouse in accordance with sanitary requirements, as well as timely debarking of round timber. However, wood can also be affected by insects in structures. In this case, they are fought chemicals, by treating wood with poisonous substances - insecticides that kill insects and their larvae. Wood is treated with insecticides by impregnation, spraying, coating, dusting with powders or fumigating with gases. For these purposes, the already described oily antiseptics and preparations on organic solvents are used, as well as DDT powder and paste (dichlorodiphenyltrichloroethane), a solution of chlorophos (dimethyltrichlorooxyethylphosphonate), chlorodan in the form of dust and emulsion and other substances, as well as some gases (chloropicrin).

Protection of wood from fire. When igniting wood with a flame, ignition occurs at a temperature of 260 ... 290 ° C, and when heated above 350 ° C, the gases released from the wood can ignite even in the absence of an open flame. With prolonged heating, these temperatures decrease. To prevent fire, take special measures, which come down to: constructive (removal of wooden elements from heat sources, installation of fire-resistant partitions and walls); covering wooden elements with plaster or cladding with low heat-conducting and fireproof materials (asbestos, etc.); painting wooden structures with fire-retardant paints or impregnating wood with special substances - flame retardants.

Fire retardant paints contain a binder, fillers and flame retardants. For example, in silicate paints, the binder is soluble glass, and the filler is ground glass. quartz sand, chalk, magnesite. The constituent components of such paints form vitreous films that prevent the access of air oxygen to the wood and protect it from fire.

To protect hidden wooden elements of buildings and structures (rafters, battens, etc.) from fire, fire-retardant pastes based on clays, lime, gypsum, superphosphate are used, which, after drying, form a fireproof layer 2 ... 3 mm thick.

Flame retardant effect of flame retardants It is based on the fact that some of them create a melted film when the wood is heated, blocking the access of oxygen to the wood, while others emit non-combustible gases at high temperatures, pushing the air away from the surface of the wood and at the same time diluting the combustible gases released from the wood itself during heating. Borax Na 2 B 4 O 7 * 10H 2 O, ammonium chloride, sodium and ammonium phosphate, ammonium sulphate are used as fire retardants. Treatment of wood with flame retardants is carried out by the same methods as antiseptic treatment.

Most antiseptics and chemicals to protect wood from insects and fire have a harmful effect on the human body, causing poisoning and burns. When handling them, you must comply with the requirements of labor protection and safety.