All about wood fire protection

Fire protection of wood is a very urgent task. Special processing of wood with fire retardants, including 1 and 2 groups of effectiveness of varnishes and impregnations, can significantly reduce the likelihood of fires, increase the chances of saving people and material values. But it is extremely important to acquire only the best refractory products and apply them correctly.

The use of wood for the construction of buildings and structures, for the decoration of their individual parts has a very long history. But even this excellent, natural and almost safe material has an "Achilles' heel" - the wood is not resistant enough to an open flame. The problem is being successfully solved using special modern technologies. There are many ways to increase the fire resistance of wood.

This category includes processing methods that allow you to get practically fireproof wood. The use of such formulations guarantees a loss of a maximum of 9% of the combustible sample (for a certain test time). The normative limit of resistance is 2 hours 30 minutes. Basically, the purpose of such processing methods is to protect wood in public buildings and at facilities with increased responsibility.

Wood materials of this class are considered to be hardly flammable in case of fire. The spread of mass loss will be from 9 to 30%. According to other sources, this figure cannot exceed 25%. Time barrier of fire resistance - 1 hour 30 minutes.

Wood of this level has practically no protection against open flames. Or, this protection is rather conditional. It is invariably found during the tests that the substances used give only a very weak refractory effect, and the weight loss is also invariably exceeding 30%. According to other sources, the third group includes wood, which loses more than ¼ of its mass when ignited.

Wet plaster is sometimes used to increase the durability of wooden products. It has to be applied in a thick layer. Dried plaster reliably insulates against open flames:

• walls;
• separate partitions;
• rafters;
• wooden columns;
• balustrades;
• pillars.

The main advantage of this method is its low cost and high level of security. The tree is surrounded by an insulating shell on all sides. It is not just a fire that is excluded by contact with a torch, match, lighter or blowtorch. Even prolonged exposure to high temperatures (for example, from a household stove) will be safe. However, such protection has much more negative properties.Plastering is a very laborious process, and in aesthetic terms, it is not very good.

Especially a lot of problems are caused by the plaster protection stratified from long-term use. It is also not suitable for delicate items. Finally, the tree itself is hidden from view - which can hardly be a plus in terms of design. Nevertheless, this method of fire protection is still preserved in a number of old and very old buildings, mainly in warehouses and attics. There, partitions, rafters, sometimes ceilings and technical shelves were protected with plaster. And yet, now it is hardly worth considering such an option.

A more modern solution is the use of pastes, coatings, mastics. In essence, they perform the same task as plaster. However, the finish looks a little more aesthetically pleasing, and there are no problems when applying it. Instead of lime, non-combustible binders are taken as a basis and water is added. The variety of fillers is very large - it is clay, and mineral salts, and vermiculite.

You can lay out protective substances using trowels, coarse brushes, spatulas. And yet the aesthetics of such coatings are not very high. They are mainly used in production, storage and auxiliary facilities. A large number of greases, pastes and similar formulations have been developed. Among them are intumescent coatings, superphosphate coatings, and so on. The use of such funds is quite effective by modern standards.

You can also protect the tree with cladding. The bottom line is that the wood is covered with a non-combustible material and does not come into direct contact with fire or a heat source. The difference from the previous options is that this is a completely aesthetic technique. However, it is worth considering the severity of the protection, the impossibility of covering geometrically complex structures, the absorption of the volume of rooms. For fire retardant cladding, the following can be used:

• brick;
• ceramic tiles;
• fire resistant sheets;
• a natural stone.

Many experts consider impregnation to be the optimal protective agent to protect wood from fire. It does not increase the load, does not diminish the aesthetic appeal of wood. You can impregnate anything - glued laminated timber, furniture, and finishing structures. Geometric shape, wood species, specificity of its application do not play a role. A typical impregnating compound is a solution of salts in water. It is these mixtures that are called fire retardants for their specific composition.

Additionally, the impregnation includes components that increase adhesion, special dyes. The role of the coloring components is not aesthetic, as one might think - they are needed to make it easier to control the ratio of already treated and not yet finished areas. Impregnation can be carried out in surface and deep format. The second method is much more complicated, requires the use of impregnating baths and cannot be carried out in the field. But the high cost and complexity are paid off by the increased security.

The technology of protecting wood with your own hands with paint appeared relatively recently. This approach was made possible by the introduction of modern formulations to ensure safety even with a relatively thin outer layer. Good dyes insulate wood not only from fire in the proper sense, but also from surface smoldering and strong heating. There is also a colorless protective paint that does not affect the aesthetic properties of structures.

Important parameters:

• no effect on the structure of the source material;
• suitability for finishing public places and even objects of architectural heritage;
• antiseptic characteristics;
• the ability to protect wood also from moisture;
• quite high price.

This method of passive fire protection of wood is also used quite often. In most cases, varnishes provide a low flammability of the material.They are not only suitable for a clean wood layer. It is quite possible to process wood-derived materials and structures with the same compounds. There are much more colorless varnishes than colorless paints, and they are no less, and sometimes even more reliable.

But there are also opaque matte, semi-matt varnishes that give an expressive design effect. They can be matched to any design idea. Lacquer is allowed to cover wood and wood products both indoors and outdoors. It is allowed to use such substances for fire protection of cabinet furniture. There are one-component and two-component varnishes, the choice between which must be made taking into account the specific circumstances.

Manual painting or application of another fire retardant layer is possible only in small areas. With a significant amount of surfaces, this method is impractical and takes up a lot of valuable resources. Simple pneumatic spray guns are not suitable for highly viscous flame retardant mixtures. Only specialized painting machines in which paint is supplied by airless method can do the job normally. The mixture is supplied by a pump, and then thrown out through a hose into a special nozzle due to the increase in pressure.

The nozzle is designed in such a way that the jet is crushed into a mass of small droplets. As a result, the surface is covered as evenly as possible. Piston or diaphragm pumps are responsible for pumping paint. In most cases, the pump is driven by an electric motor. Sometimes a carburetor internal combustion engine or pneumatic system performs the same function.

Typically, fire retardants last for several years. However, there are mastics and pastes that retain their characteristics for at least 10 years. If the manufacturer has not declared the warranty period, or information about it is lost, operation is permitted no more than 12 months from the date of processing. Unless it is explicitly stated how long the fire retardant can last, this period is assumed to be equal to the warranty period.

Even if the service life is declared longer than 36 months, it is still worth re-processing every 3 years. The negative consequences of fires are too serious to "joke" with them. In the absence of any instructions, as already mentioned, new treatments should be carried out annually, and this requirement is directly recorded in the government decree.

To check the characteristics of fire protection, they always start with a visual inspection. There should be no splits, cracks, poorly processed places. Additionally, instrumental control is carried out by destructive methods. When an emergency check is needed, the PMP 1 test apparatus and its analogs are used.... A special probe will help to determine the thickness of the layer.

It is also recommended to take shavings and evaluate the degree of their flammability. In especially difficult cases, as well as before the introduction of new compounds into circulation, a complicated practical test is carried out. Its order is described in GOST 16363-98. In such a test, a well-protecting impregnation should reduce the weight loss by up to 13%. A full-fledged examination and determination of efficiency can only be carried out by special specialized structures that are entered in the register of approved organizations of the Federal Accreditation Agency or SRO.

The frequency of testing is determined by the schedule provided by the manufacturer in the instructions for the fire retardant. If there is no such schedule, it is more correct to focus on the warranty period declared by the performer of the impregnation work. After processing, there should be no areas that have not been impregnated.There should also be no cracking, chips and other types of mechanical defects. The applied layer itself is checked for compliance with fire safety requirements.

If any violations are detected, the supervisors draw up an order. It not only describes the identified shortcomings, but also sets the date for the next follow-up visit. If no deviations are found, an act for fire protection works is drawn up. It must contain the consent not only of the fire authorities, but also of the customer, as well as the contractor. In the absence of such an act, the operation of fire protection is not allowed!