Comparison of cement base fireproof coating and expansion fireproof coating in terms of technical and price
» Cement base fireproof coating
The fireproof coating of the base is a special cement mortar that is sprayed on the structural components by the shotcrete method in order to improve the thermal inertia. Fireproof coating mainly consists of vermiculite, cement, glass fibers and special chemical additives. The fact that this composition is called cement base is precisely because of the role of cement as an adhesive. Sometimes gypsum is also used as an adhesive, and from this point of view, gypsum base coating can also be designed.
• Vermiculite is the key component of cement base fireproof coating
Vermiculite is a key component in fireproofing. Vermiculite is hydrated iron, aluminum, magnesium silicate. Based on the data available in the database of the World Association of Vermiculite, different uses have been mentioned for it; Application in agriculture, production of environmentally friendly brake pads, application in packaging and finally application as a fireproof coating.
Raw vermiculite sees and blooms in a heat process. In this process, its specific weight is reduced to about 100 to 300 kg/m3. The basic structure of vermiculite is such that it is a good insulator at high temperatures to prevent heat penetration to the steel core, and when combined with cement, it forms a relatively efficient mortar, which, when combined with other components such as glass fibers, forms the basic fireproof coating. It becomes cement.
Cement fireproof coating is cheaper than other types, but it is applied on surfaces with thicknesses (about a few centimeters). In many cases where it is technically not possible to implement high thicknesses (such as cable trays), this type of coating cannot be used. But it is suitable for buildings and metal structures where the limit for the thickness of the coating is less.
» Swelling or expansion fireproof coatin
This coating is composed of mixing water-soluble polymer with organic and inorganic materials. This coating is liquid and has a low thickness of about 2 to 4 mm and is applied on the surfaces and in some cases it shows its superiority when the thickness A thin layer of these materials should be considered for coating. This coating is not usually considered as heat insulation, and for electric cables that need to exchange heat with the environment, it is implemented with a low thickness of about 3 mm.
When a fire occurs, this composite changes its volume due to heat and creates a porous coating that, like insulation, protects the coated object from fire and prevents it from spreading. In this case, in addition to the role of extinguishing And delaying the flame and cooling the surface by releasing non-toxic gases, it also plays the role of thermal insulation.
Compared to similar materials, these materials have the advantage that despite the properties of fire protection, they have adhesion and flexibility, and are especially suitable for cables that are flexible materials and can be straightened. They are not seen. In addition, it does not contain halogenated and toxic substances and does not release toxic gases.
Inflating or expanding fireproof coating is first in liquid form. When using this material, add a little water to it and after it is homogenized, it is applied by spraying or brushing on the surface of the cables in the form of a coating with a thickness of about 2-4 mm.
After a few days of application on the cables, the coating dries and sticks to the cables in the form of putty. This composite has full adhesion to the cables and is flexible and does not fall off due to the bending of the cables. Even though this product is water-based, after the coating dries On the desired surface, it no longer dissolves in water and has good resistance, and is perfectly suitable for wet places and tunnels.
In terms of price, the inflatable or expansion fireproof coating is more expensive than other coatings. But with a much lower thickness, it creates the same efficiency. In many cases, especially in industries, it is technically possible to implement fireproof coating with thicknesses There is no higher (such as cable trays or fuel related installations). In such cases, the expanding fireproof coating is a suitable solution for fireproofing the surfaces.