Styrofoam - characteristics and selection criteria
Heating apartment in the winter costs us oh how expensive and energy prices each year grow excessively.It is a pity when so expensive avoids useless heat goes out of the apartment.And these losses are huge.However, there is a good way to reduce them: lacing external walls foam, otherwise, polystyrene, slabs.This is familiar to all polystyrene characteristics in terms of thermal insulation is quite remarkable.But is it good the other properties?Today we tell about this.
- Properties of Styrofoam - detailed and available
- whole truth about safety, flammability and durability
- As unerringlyselect polystyrene
- Video: Polystyrene foam - the pros and cons
Properties of Styrofoam - detailed and available
first look at the technical characteristics of polystyrene, which really match this insulation, later touch on those moments of its properties that arecontroversial, but always moving vendors and m
foam thermal conductivity is not nothing but a lot of air bubbles enclosed in a thin shell of polystyrene.The ratio is as follows: two percent polystyrene, the remaining ninety-eight - air.The result is a kind of solid foam, hence the name - polystyrene.The air is sealed inside the bubbles, whereby the material is excellent at trapping heat.It is known that the air layer located without moving - a great insulator.
Compared with mineral wool thermal conductivity of the material from below.It can have a value from 0.028 to 0.034 watts per meter per Kelvin.The denser the foam, the more the value of its thermal conductivity.So, for the extruded polystyrene foam having a density of 45 kilograms per cubic meter, this parameter is 0.03 watts per meter per Kelvin.When this is meant that the ambient temperature does not exceed seventy-five and fifty degrees below zero Celsius.About
vapor permeability and moisture absorption
usual foam has zero water vapor permeability.A characteristic of extruded polystyrene, which is made in a special way, are different.Its water vapor transmission rate varies from 0.019 to 0.015 kilograms per meter per hour Pascal.This seems odd, since, in theory, such a material with a foam structure of the steam is not able to pass.The answer is simple - in the dense extruded foam molding is produced by cutting.That steam penetrates through these incisions, climbing into the air cells.Conventional foam also is usually not cut, so it is not available for steam.
Regarding the absorption of water, the situation is reversed.If the sheet is simply immerse the foam in water, it will absorb it to 4 percent.Thick polystyrene, manufactured by extrusion, remains almost dry.It will absorb water ten times less - only 0.4 percent.
Video: Styrofoam breathing
Here palm belongs extruded polystyrene, in which the connection between the molecules is very strong.Static bending strength (0.4 to 1 kilogram per square centimeter) it is clearly superior to the ordinary foam (its strength lies in the range from 0.02 to 0.2 kilograms per square centimeter).Therefore, in recent years the ordinary, not extruded, foam is produced less and less, since it is less in demand.The method of extrusion provides a more modern material for insulation, durable and moisture resistant.What
Styrofoam Styrofoam does not react to substances such as baking soda, soap and fertilizers.It does not interact with bitumen, cement, gypsum, lime and asphalt emulsions.It transcends him and groundwater.But turpentine acetone, certain brands of varnishes and linseed oil can not only damage, but also to completely dissolve the material.Soluble in most foam products obtained by distillation of crude oil, as well as some alcohols.
's just not like polystyrene (neither ordinary nor extruded) to direct sunlight.They destroy it - at constant ultraviolet irradiation the material is initially less resilient, losing strength.After that complete the work of destruction snow, rain and wind.
Video: Foam and acetone - chemical experience
about the ability to absorb sound
If you need to escape from excessive noise, polystyrene absolutely no help.Impact noise he was somewhat muted in the state, but only under the condition that will be laid fairly thick.But air noise waves which propagate through the air, foam is too tough.These design features and properties of expanded polystyrene - hard-located with the air inside the cell are completely isolated.So for sound waves, flying through the air, it is necessary to put a barrier made of other materials.About
As it turned out, mold on the foam is not able to live.This is confirmed by American scientists, who in 2004 conducted a series of laboratory tests.These works were ordered manufacturers of polystyrene from the US.The result of their fully satisfied.
whole truth about safety, flammability and durability
In terms of ecology foam is absolutely safe - because in its production is not used Freon, smash holes in the ozone layer of the Earth.Polystyrene is capable of serving many years without losing its properties - Tests have shown that it can be repeatedly frozen and thawed, and the material quality is not affected.This material is not subject to burning, since it consists of special substances - fire retardants.All this seems absolutely correct and indisputable, but only at first glance.There are some nuances.About them talk on.
Unfortunately, air-oxidized polystyrene.Moreover, ordinary foam having a loose structure, is more susceptible to this process.The extruded material is oxidized more slowly, but it is waiting for the same fate.And even no combustion is not necessary - just a thirty-heat on the street.In the process of oxidation released plenty of harmful substances.This benzene and ethylbenzene, toluene, toxic formaldehyde, methyl alcohol and acetophenone.Just laid styrene foam also selects, as the complete polymerization of the material is in the production stage.In the meantime, the polymerization is completed, the allocation of styrene stops.
foam manufacturers are trying to challenge the information about the harmfulness of Styrofoam.They say that their raw material is less harmful than wood.It refers to the allocation of a tree of harmful substances during combustion.This is not true - if polystyrene is heated to a temperature higher than 80 degrees, a "bunch" of substances will come up - where there is a tree.It is time to use a gas attack generated by burning noxious black smoke.They contain, for example, phosgene (karbonildihlorid), hydrogen cyanide (gidrotsianid), hydrogen bromide (hydrobromide).
In fact any polystyrene burns.Cunning manufacturers, stating that he dies alone, being less dangerous than wood - alas, it is not.Such a statement is clearly contrary to the Russian GOST 30244-94, in which foam flammability assigned to groups G3 and G4 - the most dangerous.
Speaking of fire styrofoam manufacturers cheat by using European standards, which differ from domestic ones.There's flammability is determined by the estimated three characteristics: the biological, chemical and complex.According to the first of these, the most dangerous of zagoraemosti material - this tree.But this toxicity is determined very roughly, not in its entirety.And all the harm to compare the products of combustion of wood and foam in this way is impossible.With the chemical method, the situation is the same.
But complex technique, which in Europe is common to use when checking the polymers capable of giving true results.But the Russian company selling foam from Europe, providing customers specifications polystyrene show a biological and chemical tests of the material.Similarly, received and some domestic manufacturers of foam by opening only a part of the information consumer.So the truth is hidden from the masses.
Another way to distort the facts is a spectacular hanging foam plates in the air, and then its ignition.For this, the bottom plate exposed burning burner.The result speaks for itself - only to burn the piece, which is in contact with the burner and the fire does not go further.But this experience does not correspond to the actual operating conditions, and can only serve as a focus.But if on the plane of non-combustible material and put a piece of Styrofoam to burn, she did not go out.After flaming droplets foam produced by heating a small piece of to suffer a fire on the entire surface.The result did not take long - a plate will burn completely.
If you take Styrofoam, not including the flame retardants, its coefficient of the smoke is 1048 square meters per kilogram.In self-extinguishing foam effect, the figure more - 1219 square meters per kilogram.In rubber, for example, it is 850 square meters per kilogram, while the tree and even less - only 23 square meters per kilogram.To make it clearer, we present the following figures: if the smokiness in the room more than 500 square meters per kilogram, then stretched out his hand, you can not see her fingers.
retardants (often geksabromtsiklododeksan) is added to the polystyrene to increase its fire.In our country, usually denoted by a foam letter "C".This should, in theory, means that the material has the property to fade on their own.But in practice it turns out that a fire retardant polystyrene foam burns are not worse than not containing this additive.He just lights up worse, not doing this spontaneously at elevated temperatures.Class of its flammability - T2, but after a few years, he transformed into a T3 or T4 - retardant properties deteriorate with time.
If properly operated polystyrene, closing it from above the plaster or other protective and decorative layer, it will last 30 years, no less.However, in reality it is not so rosy - that master blind insulation hastily somehow, the customer will try to save the expense of materials, then let us make mistakes inexperienced master installation polystyrene plates.
One of these errors - wrong calculation of the thickness of the insulation.Many people think that if you take a thick slab of foam tridtsatisantimetrovuyu, then it will last longer, and the house is warmer.But it is not - a thick material by temperature changes will cracks and waves that will penetrate under the cold air.It should be noted that in Europe the accepted norm - to insulate the house from the outside with polystyrene foam no more than 3.5 millimeters thick.This allows you to reduce the risk of fire poisoning.
As correctly choose the polystyrene foam
is one of the most popular building materials.It is lightweight, warm and cheap, and working with him is easy.Since demand is high, then the offers from manufacturers there are more.And each of them says that it is his foam - the best, but the quality is beyond praise.
1. Being lost on the countless number of proposals, do not rush to buy the material.Please carefully review its options.If you need to warm facade, take polystyrene PSB-S, positioned as self-extinguishing.Make it should not be below the fortieth.And if the brand has a number of 25 or less, then do not look in the direction of the material - except that it is suitable for packing, but not for construction work.
2. Keep in mind that the foam PBS-C-40 (the fortieth brand) may have a different density - from 28 to 40 kilograms per cubic meter.The manufacturer profitable way mislead consumers - for the production of lower density polystyrene leaves less money.Therefore we can not be guided only by the number in the name of the brand, and it is necessary to ask to see the technical characteristics of extruded polystyrene foam.
3. And be great if you tell exactly how the manufactured polystyrene.After all, if the density of more than 35 kilograms per cubic meter, it should only be extruded.Conventional manner without using high compression, can achieve the density of not higher than 17 kilograms per cubic meter.
4. Before buying try to break off a piece of material from the edge.If this is a low-grade packing foam, he broke with the uneven edge, the sides of which will be seen around the small balls.The material is produced by extrusion, the site is accurate fault regular polyhedrons.The fault line will pass through some of them.
4. As for manufacturers of expanded polystyrene, the best of them are European companies «Polimeri Europa», «Nova Chemicals», «Styrochem», «BASF».Not far behind them and Russian manufacturers, such as "Penoplex" and "Technonikol."They have the production capacity, which is enough for the production of expanded polystyrene is very high quality.
Conclusion Although the foam, as it turned out, is dangerous when burning and emits harmful substances at the same time, it remains one of the most popular thermal insulators.After all, as expanded polystyrene insulation has many advantages: it is the cheapest, easy to cut with a knife usual, hardly absorbs moisture and keeps the heat well.No wonder the four European building of five have just expanded polystyrene insulation facade.And as houses and offices, and production facilities.
However, to talk about long-term studies of this material is too early - even half a century had passed since the beginning of its use.Therefore, those who talk about the service life of more than 80 years of polystyrene, can confirm his words only tests under laboratory conditions.But they absolutely believe it is not necessary - in fact, in order to get the desired results can be specific samples to the lab to send.
most important in the operation of expanded polystyrene in the environment - safe shelter him from the sun and weather.To do this, use a mixture of plaster, which includes cement.The coating should be applied firmly, should not remain a single lumen.Otherwise, a tiny ray of sunshine may eventually completely destroy the insulation.
But inside foam for thermal insulation used is not necessary, no matter what the manufacturer claims.Let them speak, but because in the event of a fire they will not close, but the toxic products of combustion can cause great harm, taking health, and sometimes even the lives of people.An example would be known to all the tragedy in the Lame Horse club, where most visitors simply suffocated the products of combustion of the heater.