Comparative fire resistance test expanded polystyrene, basaltic mineral wool, Gutex wood fibre boards

European studies carried out years ago have shown that a large part of energy resources is consumed in heating and cooling homes. Lack of thermal insulation, poorly chosen construction solutions and inefficient windows lead to a significant and continuous heat flow between indoors and outdoors, increasing energy consumption. As a result, regulations have emerged to make buildings more energy efficient, and insulating old houses has been one of the measures proposed. Different types of thermal insulation materials have appeared on the market and, of course, comparative discussions on the advantages and disadvantages. In addition to insulating capacity and price, the property that still arouses most interest is fire resistance. Participating in Naturalpaint event on Gutex thermal insulation materials, gave us the opportunity to see "live" a comparative fire resistance test of three insulation materials: polystyrene, basaltic wool and Gutex wood fiber board.

Fire-resistant insulation can save lives

How the external insulation of a building is done is essential, not only for thermal and acoustic comfort but also for fire safety. If the facade is insulated with a combustible material, in the event of a fire, it will start to burn, becoming a source of fire and toxic smoke. As the fire spreads, it will become a major hazard to the inhabitants of the building.

By insulating with a non-combustible material, even if the flames spread and reach, for example, the upper floors, the facade will not contribute to the spread of the fire or give off toxic smoke. Non-combustible (non-combustible) insulation can slow the spread of the fire, which would give more time for occupants to leave the building and for firefighters to act. In such situations, every second counts if people are to be rescued and the fire can be extinguished.

In terms of fire behavior, there is a big difference between the materials used to insulate buildings.

Expanded polystyrene, for example, reacts almost immediately to fire, giving off dense toxic smoke. It is made from styrene monomer, a hydrocarbon derived from petroleum, making it a cheap and affordable alternative. The polar opposite is basaltic mineral woolwhich is non-combustible, withstanding very high temperatures before melting. It is made from basaltic rock, which is thermally and mechanically formed into insulating panels or blankets. Fiber insulation is made from wood, a material recognized as combustible. It sounds hard to believe, but the way it's made makes it highly fire-resistant, comparable to basaltic clay.

Insulations comparison test: expanded polystyrene, basaltic wool and wood fiber panels

During the workshop organized by Naturalpaint, a comparative fire resistance test of the three thermal insulations mentioned above was carried out. Three panels identical in size were used: one made of expanded polystyrene, the most commonly used insulating material in Romania for facades, a second made of basaltic mineral wool, a non-combustible material, and a third made of wood fiber. The test movie can be watched below, at the end of the article. For other news subscribe to our YouTube channel.

The panels were framed in a wooden frame with the insulation separated from each other. Drywall was applied on one side of each type of insulation, thus reproducing the real conditions (the insulation is not left "exposed"). The fire source was provided by 3 identical burners with their own taps, one for each panel, attached to a gas cylinder. The flame was applied at the same time for all 3 types of insulation, from the drywall side, in the center of the panel.

The first to fail was the expanded polystyrene panel. Less than a minute after ignition, without the fire penetrating the plasterboard, the temperature of the polystyrene quickly reached 300°C, began to melt, emit toxic smoke and odor, and the board punctured a hole in the flame. After the burner stopped, the smoke continued to billow for another 1-2 minutes, the hole in the center of the panel widening.

For the other types of insulation the experiment continued for another 20 minutes. After 5 minutes, despite the fact that the fire was burning on the plasterboard side, on the other side the temperature of the panels was as it had been at the beginning. It was possible to hold one's hand on the panels and no odor or smoke was emitted. After 13 minutes, the temperature in the basaltic wool panel rose quite quickly to 170°C, that in the Gutex panel rising only to 60°C, without being pierced by the flame. After 17 minutes the wood fiber panel could still be touched by hand. The temperature in the basaltic wool insulation reached 340°C and the panel darkened on the side opposite the flame, but was not pierced. The burner was turned off so that the Gutex panel test could continue without the risk of running out of gas. The fire resistance of basaltic glass wool is recognized, it does not burn but melts at temperatures above 1000°C.

The remaining wood fiber panel changed color 21 minutes into the test. Smoke and odor specific to wood burning was eliminated. As the burning continued, a smoldering flame appeared next to the flame, but did not extend to the entire panel. The test was stopped after 25 minutes without the wood fiber panel burning with flame. The smoke released was mostly from the wooden frame which the flame sometimes reached due to wind.

Gutex wood fiber insulation

Gutex Holzfaserplattenwerk has been manufacturing fiberboard since 1932, using pine and spruce waste from wood-processing factories. The boards are environmentally friendly because only untreated wood is used, and the manufacturing processes are very "clean", with little additives added. The insulation contains only 3-4% polyurethane adhesive needed to form the board, 2% paraffin for water resistance and under 1% natural salts for rodent and fire resistance.

Gutex wood fiber thermal insulation is available both in sheets and as individual fibers. Fiberboard are of different thicknesses, sizes and flexibilities and can be used for insulating ventilated facades and exterior walls, interior walls, prefabricated walls of timber frame houses, roof insulation, between rafters, between floors or under floors. In order to be as easy as possible to install and to eliminate thermal bridges, the boards are manufactured with the nut and feder fastening system. Individual fibers are used for insulating difficult and tight spaces in attics and lofts or any other hard-to-reach place that requires isolation.

Gutex products for thermal and sound insulation of buildings are distributed in Romania by Naturalpaint.