Stone wool is often used to warm houses - after all, it is not afraid of fire, and is easy to install, and is inexpensive. And one of its most popular types is basalt insulation, the technical characteristics and properties of which depend on where it is used specifically. By the way, we note that this material is one of the cleanest in terms of ecology.
Cotton wool from basalt - and this is possible
Since this insulation is a type of mineral wool, it has several names, among which - basalt or stone, wool. Moreover, it not only surpasses all other types of mineral wool in strength characteristics, but is also absolutely safe for humans and nature. Compared to mineral wool made from slags of metallurgical production, basalt insulation is more environmentally friendly, easier to cut and assemble, and lasts longer.
The molten gabbro-basalt rocks forming thin fibers form the basis of basalt wool. By and large, this is fiberglass, not from quartz, but from basalt. And the material was invented (or rather, noticed) by the Hawaiians. Once, when one of the volcanoes once again spewed lava and cooled, the locals found amazing fibers in the remnants of the lava, long and strong. Later, what was done by nature, people were able to repeat, inventing the production of basalt fibers.
Volcanic rock - basalt.
To do this, the rock must be crushed and melted. The temperature in the melting furnace is very high - 1500 degrees, not less. Further, the melt enters special drums, where it rotates, blown by an air stream. The result is a fiber with a thickness of not more than 7 microns and a length of not more than 5 centimeters. To make the fibers resilient and strong, a special composition is added to bind them. Then the cotton wool is heated to 300 degrees, passing through the press 2 times.
About the characteristics of stone wool
Thermal Conductivity - Low
The fibers in the basalt insulation do not have a strict orientation, but are located very randomly, so the structure of the substance turns out to be airy. Countless streaks of air between thin stone fibers - an excellent heat insulator. Therefore, the thermal conductivity of this material is very small - its value ranges from 0.032 to 0.048 watts per meter per Kelvin. This corresponds to the level of cork, foamed rubber and expanded polystyrene, both extruded and ordinary.
Let's try to compare the technical characteristics of basalt insulation and other materials. Take, for example, 10 cm. Mat from basalt insulation, whose density is 100 kilograms per cubic meter. For the effect of heat preservation to be similar, it is necessary to erect a ceramic brick wall 117 cm thick. If the brick is made of clay, then the wall should be even thicker - 160 centimeters. A two-meter wall will have to be laid out of silicate brick, and the layer of wood should be at least 25.5 centimeters.
Moisture absorption - almost zero
This material has the property of hydrophobicity. Water falling on it cannot penetrate inside, due to which the thermal insulation properties do not change. But if you conduct a similar experiment with ordinary mineral wool, then it will absorb a fair amount of water. Wet cotton wool will not hold heat - after all, water entering its pores significantly increases the thermal conductivity of the material.So if you need to warm a humid room, for example, a sauna, then take not ordinary glass wool, but basalt - you will not be mistaken. Water absorption by volume is not more than 2%.
Water does not impregnate, but flows around the fibers of basalt wool, because in the production process it is impregnated with special oils.
The ability to pass steam is excellent
Basalt fiber, regardless of its density, has excellent vapor permeability. Moisture, which is contained in the air, easily penetrates through the insulation layer, without forming condensate inside it. This is especially important for a bath or sauna. Basalt wool itself does not get wet, still storing heat reliably. Therefore, in rooms insulated with this material, it lives comfortably - temperature and humidity conditions are optimal. The vapor permeability is about 0.3 mg / (m · h · Pa)
Fire Resistance - High
In accordance with the requirements that firefighters make, cotton wool from basalt fibers is considered a non-combustible substance. But that is not all - it is able to block the path to open fire. The maximum temperature that basalt insulation can withstand without reaching the melting point is 1114 0C. This allows it to be used to isolate devices operating at high temperatures.
If we consider the indicators of this heat insulator for fire safety (determined by NPB 244-97), then stone wool is considered to be non-combustible materials (NG group). So it is determined by GOST 30244 and SNiP 21-01-97. Thus, there are no prohibitions when using this insulation. Any buildings, structures, structures and structural elements can be insulated with this material.
Video: Testing basalt wool for flammability
Sound Barrier - High Level
As for the acoustic properties, they are also good with basalt wool - in the sense of sound insulation, of course. This insulation is able to muffle vertical sound waves traveling inside the walls. Thanks to this, the room is well insulated from external noise. Absorbing sound waves, stone wool reduces the reverberation time, which protects from noise not only the room whose walls are insulated with this material, but also neighboring rooms.
Material strength
Basalt fibers inside the material are randomly arranged, and some of them go in the vertical direction. Thanks to this, not even very dense stone wool is able to withstand considerable loads. So, at 10% deformation, basalt wool has compressive strengths of 5 to 80 kilopascals. The specific value of this indicator depends on the density inherent in this brand of material. Such strength characteristics of basalt wool guarantee that the heat insulator will serve for a long time without changing its shape and size for the entire period of use.
Fibers of basalt wool.
Biological and chemical activity - low
Stone wool is chemically passive - this is its undoubted advantage. If it is laid close to a metal surface, then you can be one hundred percent sure that rust will not appear on the metal. And to aggressive biological environments basalt insulation is quite calm. Neither rotting nor mold damage and other harmful microorganisms are characteristic of it. He steadily withstands the invasion of rats and mice on the house - after all, these rodents made of stone wool cannot handle their teeth. High resistance to aggressive substances allows the use of this insulation to isolate many technical structures that work in difficult conditions.
Safety is OK
Stone wool is made from natural raw materials - basalt mineral. Its fibers are bonded with formaldehyde resin. It gives the material the necessary strength characteristics, and also makes it more dense. Although they say that phenol is dangerous, but not in this case. Indeed, it cannot stand out from basalt wool, since it is completely neutralized even during the production of the material.However, at the stage of manufacturing this mineral insulation, phenolic fumes are extremely small - much less than the allowable limit of 0.05 milligrams per m2/hour.
Unlike glass wool fibers, basalt fibers do not irritate the skin, do not prick and do not cause allergies. Today in the construction market there are a large number of brands of stone wool of various densities, the technical characteristics of which are somewhat different from each other. But all types of basalt insulation are distinguished by their strength and long service life.
Where is basalt cotton wool used?
This insulation can be used in almost all building structures. They can isolate as a roof of any shape, and walls, partitions, ceilings. In addition, due to its characteristics, basalt insulation is quite suitable where another insulator is completely useless. Next, we list where it will be especially practical to use this material.
- Rooms with high humidity, such as saunas and baths.
- Facades of the hinged ventilated type, "wet" facades.
- The walls are made of sandwich panels, as well as made using layered masonry.
- Cabins on ships, as well as other ship structures.
- Pipelines of various types, the surface temperature of which can be from minus 120 degrees Celsius to plus 1000 degrees Celsius.
- Also, basalt material successfully serves as an obstacle to fire, perfectly protecting ventilation pipes and building structures from fire.
Note that it is very successful to use hard mats from this mineral insulation where sufficiently large loads are expected. They can be both installation and operational. If you need to insulate a ventilated facade, it is best to take basalt cotton wool, consisting of two layers. Each layer has a different density, with a looser layer located inside, on the side of the walls. The second layer, having a denser structure, should be outside, on the ventilation side.
When constructing a suburban cottage with a small number of floors, the basalt heat insulator may also be the best choice. It is good for warming any structural elements: roofs, ceilings, facades, walls and partitions. And where it is very humid (in baths and saunas) basalt cotton wool is just a real salvation. Especially considering the ratio of the excellent technical characteristics of basalt wool as a heater, its excellent quality and reasonable price.
On the minuses of basalt insulation
1. It would seem that everyone is good at this material. It is both durable and warmly saves perfectly, and extraneous noise will not allow into the house. But he also has shortcomings, although there are few of them. To begin with, we mention a fairly high price. Unfortunately, not everyone can afford this wonderful natural basalt fiber insulation.
2. The presence of seams in those places where the individual elements of the insulation are connected, makes the insulation layer not tight enough.
3. Despite the fact that basalt fibers are soft and do not prick hands, tiny pieces may break off them during installation. As a result, a column of fine basalt dust rises from the heat insulator. And inhaling this dust does not smile at anyone - it certainly will not contribute to improving health. Put on a respirator before working with a heater - and everything will be all right. And to eliminate dust, the finished surface of basalt wool is covered with a layer of a waterproofing membrane.
4. Due to the good ability to pass steam, it is not advisable to use this insulation in some cases and it is better to replace it with the same polystyrene foam. For example, when warming the basement or foundation of the house.
