Is polyurethane foam harmful to humans? PPU: what is it and why is it needed. Specifications PPU
Everyone knows that good health and good mood depends on a comfortable and comfortable bed. The mattress gives it such qualities. Sleeping on an uneven and sinking mattress will not only prevent a person from getting enough sleep, but will also cause pain. In order to prevent this from happening, it is necessary to choose a reliable quality option at an acceptable price. These requirements are met by a polyurethane foam mattress.
What is PU foam in a mattress?
Polyurethane foam mattresses are a good substitute for orthopedic mattresses, especially since their price is lower, and the quality is no worse.
Polyurethane foam, which is the basis of mattresses, is nothing more than foam rubber, only with improved properties. The material received the name Porolon thanks to the Scandinavian company that was called that. Today, only the name remains of the quality and properties of that material. Thanks to modern technologies, foam rubber received not only a new name, but also acquired a lot of new and useful qualities that allowed it to be used in the production of mattresses.
All manufacturers producing PPU, as a rule, produce it according to one technology corresponding to a certain scheme. To begin with, two substances are mixed in certain proportions, to which water is added. During chemical reaction carbon dioxide is released, due to which foaming of substances occurs and the formation of a porous structure in the future. During the reaction, which lasts no more than 20 minutes, catalysts and stabilizers are added. Then the mass is poured into a special form and remains for two days for the final polymerization.
Thanks to the technology of mixing in certain proportions of substances, polyurethane foam, containing 90% air in its composition, acquires the main characteristics such as elasticity, heat resistance, density and rigidity.
In addition to the above indicators, the quality of mattresses is also affected by the multi-layer or solidity of this material. The basis of good mattresses is a monolithic block of polyurethane foam, having a thickness of 16 cm. In cheaper models, a multi-layer block of glued polyurethane foam layers is used. A mattress 15 cm thick will consist of five layers of three centimeters. Products based on glued blocks are much cheaper.
The benefits and harms of filler for health
It is no secret that chemicals are used for the production of polyurethane foam, this fact causes a lot of controversy about its negative impact on the body. There is confirmed evidence that the elements that make up polyurethane foam are hydrocarbons derived from oil, and during open combustion, these substances are released into the air in high concentrations. But is the components in the normal conditions not yet known.
There is an opinion that when the mattress, which includes this polymer, is heated to body temperature, a specific odor appears, caused by the release of harmful components that make up the foam. Therefore, there was an opinion that the use of this material as a filler for a mattress is unsafe. But in fairness it should be noted that the toxicity of this filler occurs only if the production technology is not followed.
Therefore, you should not save on your own health and buy a mattress from little-known manufacturers. Large firms monitor the quality of their products.
There is an opinion that a polymer that has completely reacted, that is, the technology has been observed from and to, is inert, which means it is safe and suitable for use as a filler. A barely perceptible smell and residual vapors disappear after a maximum of two weeks and further use of the mattress does not pose a threat to health.
Apart from chemical properties, according to some experts, PPU is accused of being too soft. They argue that mattresses based on polyurethane foam cannot ensure the correct position of the spine, as it flexes strongly, and the spinal column also flexes with it. Over time, this arching can lead to curvature of the spine and many other problems. For children under two years old, the use of PPU as a filler is highly undesirable, for such babies there are fillers.
But modern technologies, used in the production of polyurethane foam, allow the production of this material with improved properties. A good quality filler has stiffness indicators above average, and the cost of a mattress with polyurethane foam is much higher than that of a product with spring block. To date, it cannot be unequivocally stated that PPU is harmful to human health, but there is also no certainty that it is absolutely safe. Therefore, each person must decide for himself whether to buy a mattress in the composition, which has polyurethane foam or refuse to buy.
Advantages and disadvantages
PPU, which is the basis for the mattress, gives this product many properties. Among them there are both positive qualities and some disadvantages.
Of the advantages of this material, elasticity and elasticity should be noted. Thanks to these qualities, good support is created for the musculoskeletal system.
The reasonable price of PPU is a significant advantage. Especially when you have to choose between models with a similar cost. A bonell box spring mattress costs about the same as a foam mattress, but the benefits of a polyurethane foam product are much greater. The dependent spring block bonell is not able to provide proper support to the spine, especially since this species lacks orthopedic properties. And in mattresses with modern polyurethane foam, they are pronounced. Moreover, the polyurethane foam mattress, which is not prone to deformation, is recommended for use by people with various disorders of the musculoskeletal system.
The positive quality of this mattress is its viscosity.
Thanks to it, PPU is able to withstand significant pressure. Therefore, people with a lot of weight can safely sleep on such mattresses - there will be no dents or creases on it. Viscosity is exactly the property due to which the joint rest of couples with different weight indicators will not be overshadowed. The pressure exerted on the surface by the heavier partner does not affect the lighter partner, there is no hammock effect. In addition, due to the viscosity, the PU foam mattress does not sag for a long time.
Polyurethane foam is a polymer with a cellular structure and therefore it is able to pass air well. Breathability gives products with PPU excellent hygienic properties. And, of course, an important advantage of a polyurethane foam mattress is its good transportability. Such mattresses are rolled up for convenience, because they are not afraid of deformations and twists.
Numerous advantages do not negate some of the disadvantages inherent in foam mattresses. Such an advantage as the price can turn into a significant disadvantage. This happens if the desire to reduce the cost of the product reaches the limit. In very cheap models, the quality suffers noticeably and the service life is significantly reduced. At best, such a mattress will last 3-4 years.
The porosity of polyurethane foam contributes to the absorption of odors, liquids and fumes, and cleaning such products at home is not possible. The polyurethane foam mattress lends itself only to specialized processing. Some inconvenience brings the smell emanating from the new mattress, but it disappears after a few days.
Which is better: holofiber, latex or polyurethane foam?
Polyurethane foam, latex and holofiber are often used in the manufacture of mattresses. In order to compare them, it is necessary to analyze the properties of materials:
- Latex- the material is natural, obtained by processing rubber wood, and PPU and holofiber are of artificial origin. Latex has an antibacterial effect, has a porous structure, a pronounced orthopedic effect, is breathable and easy to care for. Of the shortcomings can only be called a high price.
- PPU has similar characteristics to latex, but is more affordable. In addition, this material has a shorter service life compared to latex, as well as a lower load capacity.
- holofiber- the material is synthetic and most often consists of polyester, polyamide, polyacrylonitrile and some other fibers. This bulk material has a lower cost compared to polyurethane foam, and even more so with latex. The volume of the holofiber after a very short period of time decreases very much, in six months it can lose more than 2 cm in height. And yet, this material is often used in the production of mattresses, the reason is simple - its cost, and the cheaper the filler, the greater the profit of manufacturers. Hollofiber can be used in mattresses, but only as an additional layer, not a base.
Polyurethane foam and latex are more suitable as a base for mattresses, and holofiber as an additional layer.
Kinds
Exist different kinds mattresses based on polyurethane foam. These include highly elastic models with a memory effect, viscoelastic, standard, soft, extra soft, models with increased rigidity.
Most often, in the production of one polyurethane foam, manufacturers are not limited, since the height of the product is only 15 cm, and therefore various fillers are additionally put into mattresses. These include coconut coir, felt, jacquard fabric. Such combined models not only become taller and denser, but also acquire additional properties that improve the quality of products.
Coconut coir gives the product rigidity, increases the service life and has an antibacterial effect. A polyurethane foam mattress with this extra layer is suitable for children. Jacquard fabric is used for covers. To give orthopedic properties to mattresses, manufacturers make the surface of polyurethane foam embossed.
Dimensions
In addition to the degrees of rigidity, foam mattresses are classified by size. There are single, one-and-a-half, double and non-standard options. As a rule, manufacturers try to produce sizes adapted to the dimensions of modern furniture.
Single mattresses include the following dimensions: 80x190 cm, 80x200 cm, 90x190 cm, 90x200 cm and a slightly shortened version adapted to a certain type of bed 80x180 cm. One and a half models include the following sizes: 140x200 cm, 120x200 cm. These dimensions are most in demand, especially the size 140x200 cm, as it is suitable not only for single beds, but also for double beds. After all, a width of 140 cm is very common in beds designed for two people.
Double mattresses include products with dimensions of 160x200 cm, 180x200 cm. Manufacturers produce non-standard sizes only for individual orders. For example, the size is 190x130 cm, which cannot be attributed to either a one-and-a-half or a single mattress.
The height of the side is another indicator by which PU foam mattresses can be classified. Products with a height of 5-10 cm are considered thin. Models with such low sides are made either for sofas, armchairs, folding beds, or for babies. standard height mattress starts from 15 cm.
Density and hardness
This cellular filler has two main indicators: density and rigidity. The ratio of these two values affects the quality of the material, while density is a more significant indicator compared to stiffness. The higher it is, the better the mattress based on this material, and the stiffness index may be low.
Density and stiffness depend on indicators such as the permissible load on one sleeping place and the service life of the product, which is based on PPU.
The cheapest mattresses have a hardness index no higher than average, the service life of products that include such a filler is not more than 3 years, and the permissible load on a bed is not more than 90 kg. The second group includes mattresses with an average stiffness slightly higher, while the service life of such products is 5-7 years, and the load increases to 110 kg per bed. Good quality products have a service life of about 10 years, their rigidity is above average, and the allowable load increases and reaches a value of 140 kg.
Textile
As a cover for products made of polyurethane foam, various mattress fabrics are used. Most often it is jacquard, knitwear, coarse calico, polycotton and, in more expensive models, a membrane:
- Textile good quality has in its composition cotton. Thanks to him, the fabric acquires such a quality as breathability. Synthetic fabrics are less breathable than cotton fabrics, with the exception of some expensive fabrics.
- Jacquard fabric is durable and exquisite appearance. It contains both natural and synthetic fibres. Synthetic jacquard is resistant to friction, stretching and denser than knitted fabric, but inferior to it in terms of comfort.
- Used for baby mattresses coarse calico or polycotton. These fabrics have cotton fibers in their composition, thanks to which the fabric is well ventilated.
- Membrane is a non-woven fabric with high water-repellent properties. In addition, this canvas is very resistant to high temperatures, has high air permeability and crease resistance.
Colour
Companies that produce mattresses are guided, first of all, by the preferences of the consumer. For children, covers, as a rule, have bright colors. The color range intended for the mass consumer does not differ in a wide range. But this is not really necessary.
Mattresses are mainly purchased for beds installed in bedrooms already decorated in a certain color scheme and therefore bright colors will not come in handy. The most requested color is white. The best option, suitable for almost all bedrooms, decorated in any style. Sometimes there are models that have a light gray cover. In exclusive models, the cover can also be black with an interesting pattern. Askona Basic High with a side height of 21 cm, manufactured by Askona. The model can withstand a maximum load of 110 kg. Jacquard fabric at the base of the cover is resistant to friction and washing. For ease of transportation, the mattress is rolled up and weighs 9 kg.
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How to care?
In order for the mattress to serve for a long time, it must be properly looked after. Any model must be periodically turned over from one side to the other. This rule relevant not only for models with different surface hardness, but also for options with the same degree of hardness of both surfaces. Turning over is necessary to restore orthopedic properties.
To extend the life of PU foam mattresses, they need to be ventilated. To do this, it is necessary to remove the product from the base of the bed and position it in such a way that air access to both surfaces would be free. To remove dust from the mattress, it is better to use a vacuum cleaner.
In case of accidental spillage of any liquids, you can wash the stain with a soft detergent and dry naturally without the use of an iron and other heating devices.
Foam rubber is the common name for polyurethane foam (PPU). It comes from the name of the Scandinavian company Porolon, which was the supplier of this material to the USSR.
Both then and now, foam rubber remains one of the most popular materials that is used to fill furniture, soft toys, as well as sports equipment such as gymnastic mats and modules. The reason for the popularity lies in the cheapness of foam rubber, but this is practically its only plus.
Currently, manufacturers who care about the health of their customers are gradually abandoning the use of foam rubber, and are increasingly giving preference to more modern materials that meet environmental safety standards. But why is foam rubber so dangerous? Is it really a health hazard?
Harmful qualities of polyurethane foam
Turning again to Wikipedia, you can find out that the production of foam rubber itself is potentially dangerous, because. environmentally hazardous substances are used in the production process (foam stabilizers, polyols, isocyanates, various catalysts, etc.). However, manufacturers claim that these substances do not pose any danger in the composition of foam rubber, since they are in a bound state.
However, studies have confirmed that after several years of operation, the chemical compounds contained in polyurethane foam begin to decompose and be released into the environment, posing a serious threat to human health and even life. Scary? Still, because the substances that foam rubber releases have strong carcinogenic properties, which directly affects the occurrence of cancer.
Also among the disadvantages of foam rubber, the following can be noted:
- fire hazard and combustion toxicity. Polyurethane foam is a very combustible material, but even worse, when burned, it releases extremely dangerous substances (hydrogen cyanide and carbon monoxide). Of course, manufacturers are trying to reduce the fire hazard level of PPU by adding special additives, but this problem has not been 100% eliminated.
- fragility. The material quickly loses its performance characteristics- ceases to be elastic, crumbles, sticks together.
- Absorbs odors, poorly ventilated, which can lead to the spread of harmful microorganisms inside the material.
Sports mats filled with foam rubber
Given all of the above, we can conclude that foam rubber is completely unsuitable as a filler for mats, because:
- Sports mats are most often used in the gyms of children's educational and sports institutions, which means that it is children who suffer most from negative consequences use of PPU in such products.
- Foam-filled mats pose an additional fire hazard and the risk of poisoning by harmful substances released during the combustion of polyurethane foam. Naturally, in educational and sports institutions, first of all, it is necessary to exclude such equipment, replacing it with fireproof, 100% non-toxic and environmentally friendly.
- Due to the fragility of foam rubber, mats with such a filler require relatively frequent replacement, which in no way contributes to budget savings. If the equipment that becomes unusable is not changed in time, this increases the risk of injury when playing sports.
Foam rubber is being replaced by new safe materials, for example, Hollofiber, EVA material, etc. Information about
Almost no one knows that foam rubber is a polyurethane foam composition, which was imported to the Land of Soviets by the well-known Scandinavian company Porolon.
Since then, the name has stuck with it and is still practiced, since it is rather difficult to call it polyurethane foam in everyday life.
Today, when our fellow citizens are finally worried about the harmfulness of household items, it's time to write about the properties of this elastic material.
According to its properties, the material is an elastic, soft foam made from polyurethane. The hollow cells contain air, which explains its very low weight.
The scope of its application is quite wide, but the main areas remain heat and sound insulation, giving softness and elasticity to most household items, such as upholstered furniture.
In the manufacturing process of foam rubber, a large number of foam stabilizers, isocyanates, polyol, and catalysts are used. It is now generally accepted that these components can evaporate and cause significant harm to the health of those who come into contact with them. Until this fact is confirmed, and the manufacturers themselves insist that all these components are in a bound state, so they simply cannot stand out. If they are released, then under the influence of moisture in the air, they almost immediately decompose into harmless substances.
True, in some cases, polyurethane foam can be harmful to human health, since when burned, this substance emits highly toxic gases, so the material should not be allowed to ignite.
Manufacturers, to withstand high temperatures, add thermosetting substances to the foam rubber, but have not yet completely got rid of the flammability of polyurethane foam.
It is impossible to ignore the fact that the life of the foam rubber does not exceed ten years. In the future, the chemicals in its composition begin to actively stand out in the process of decomposition of complex compounds. These substances have pronounced carcinogenic properties, therefore it is not recommended to store polyurethane foam for more than ten years.
9th International Exhibition "Wooden housing construction/HOLZHAUS" was held from 13 to 16 November at the IEC "Crocus Expo". And if exhibits promoting polystyrene foam have practically disappeared at this exhibition - how effective to use insulator for low-rise wooden housing construction , then the exhibits in which polyurethane foam enough has been presented. The questions that arose during the conference held on the use of these materials in construction are answered by this article.
AT last years Foamed polymer heat-insulating materials are widely used. Indeed, from the point of view of thermal physics, these are the most effective heat insulators. But when we are talking about housing, about such a product of the construction industry, with which a person has to communicate daily for many hours for decades - thermophysical properties alone are not enough. Here the main thing is chemical safety and durability.
The main cause of chemical hazard lies in nature polymer materials. The fact is that:
1. The polymerization process does not go to the end, but only by 97-98%;
2. The polymerization process is reversible, therefore, polymers are constantly decomposing (destruction process) under the influence of light, oxygen, ozone, water, mechanical and ionizing influences, and especially under the influence of heat. The combination of these factors leads to a relatively short service life of polymers - an average of 15-20 years, after which they turn into powder.
Polymers are dispersed organic compounds that have a very high contact surface with atmospheric oxygen with the occurrence of an oxidation reaction. And the products of their oxidation, even at room temperature, have a negative impact on the environment. Moreover, with increasing temperature, the rate of oxidation increases.
All polymeric heaters are FIRE DANGEROUS and the main damaging factor in fires are volatile combustion products of foamed polymers. Only 18% of people die from burns, the rest - from POISONING.
According to the classification for fire hazard, all FOAMED POLYMERS belong to the class "G", that is, "COMBUSTABLE MATERIALS".
The problem of fire hazard of foam plastics is usually considered from two sides:
- the danger of the actual combustion of polymers (pyrolysis),
- danger of products of thermal decomposition and oxidation of the material (destruction).
Toxicological danger of polystyrene foam
At first glance, EPS foam should be the safest among organic polymers. in the process of its polymerization, foaming and subsequent degassing, the toxicity of STYRENE should be eliminated. However, POLYSTYRENE (PS), from which POLYSTYRENE FOAM is made, refers to equilibrium polymers, i.e. is in thermodynamic equilibrium with its highly toxic monomer - STYRENE (C):
PS n \u003d PS n-1 + C.
Therefore, this polymer is subject to the process of depolymerization with the release of the monomer - STYRENE.
STYRENE is a highly toxic substance. The heart suffers from microdoses of styrene, women have special problems (styrene is an embryogenic poison that causes deformity of the fetus in the mother's womb). Styrene has a strong effect on the liver, causing, among other things, toxic hepatitis. Styrene vapors irritate mucous membranes. It has the most stringent tolerance of all toxic substances (the MPC day value of STYRENE is 1500 times less than, for example, that of carbon monoxide) that can be released from building materials (see table 1)
Such a low MPC value for styrene and, accordingly, the multiple excess of its MPC norms in the room is caused by the special properties of styrene. This substance belongs to condensed aromatic compounds that have one or more benzene nuclei in their molecule, and, like similar substances (benzene, benzopyrene), has increased cumulative properties: it accumulates in the liver and is not excreted. Substances of this group are particularly dangerous. For example, benzopyrene is an active carcinogen with MPC 0.000001 mg/m3.
There are two concepts for assessing the impact of harmful substances on the human body:
Threshold. The threshold concept states that reducing concentrations harmful substances necessary up to a certain level (threshold), determined by the value of the maximum permissible concentration (MAC). The conclusion follows from this provision: low concentrations of harmful substances (below the MPC level) are harmless. In our country (as, indeed, in other countries of the former USSR), it is precisely the threshold concept that has been adopted. Linear. The linear concept assumes that bad influence per person proportionally (linearly) depends on the total amount of the absorbed substance. Hence the conclusion: low concentrations with prolonged consumption are harmful. This concept is followed by the USA, Germany, Canada, Japan and some other countries. But when considering the toxic danger of exposure to harmful substances on humans, it is necessary to take into account the degree of their COMMULATIVENESS, i.e. the ability of a substance to accumulate in the human body over time.
STYRENE among the substances contained in building materials, has the highest degree of commutativity - 0.7 (see Table 1). If we imagine that polystyrene 160 mm thick (in a three-layer panel) will last 20 years, then during this period each sq. meter outer wall will release 3 mg/h of styrene. When 10% of this amount enters the room and air is supplied in the amount of 30 m3/m2 h, the styrene concentration will be 0.0075 mg/m3. With a temporary stay in such a room and orientation to the daily MPC = 0.002 mg/m3, the excess of the MPC for styrene will be 3.75 times.
Therefore, for a dwelling with a residence time of 25 years, the MPC value for styrene should be reduced by a factor of 594 and be 0.0000034 mg/m3 (see table).
Table 1. Decrease in the MPC value of harmful substances, taking into account their degree of cumulativeness.
| Substance | MAC, mg/m3 | Degree of commutativity | MPC reduction | Recalculated MPC, mg/m3 | |
| one-time | daily allowance | ||||
| Carbon monoxide (carbon dioxide) | 5 | 3 | 0,1195 | 3 | 1,0000000 |
| methanol | 1 | 0,5 | |||
| Carbon monoxide (carbon monoxide) | 20 | 0,02 | |||
| nitrogen dioxide | 0,085 | 0,04 | 0,176 | 5 | 0,0080000 |
| Phenol | 0,01 | 0,003 | 0,2815 | 13 | 0,0002308 |
| Ammonia | 0,2 | 0,04 | 0,376 | 31 | 0,0012903 |
| Nitrogen oxide | 0,4 | 0,06 | 0,444 | 57 | 0,0010526 |
| Formaldehyde | 0,035 | 0,003 | 0,575 | 188 | 0,0000160 |
| Benzene | 1,5 | 0,1 | 0,633 | 322 | 0,0003106 |
| Styrene | 0,04 | 0,002 | 0,7005 | 594 | 0,0000034 |
Conclusion: STYRENE requires a reduction in MPC when using it in housing construction by about 600 times to the level of 0.0000034 mg/m3, which is equivalent to a complete ban on the use of POLYSTYRENE FOAM in housing construction.
Combustibility of expanded polystyrene
Due to this property, expanded polystyrene in the form of pre-foamed granules was used as a component for napalm bombs to burn enemy armored vehicles. Expanded polystyrene melts and its melt burns with a temperature above 1100ºС. It is the only polymer that burns at such a high temperature. Therefore, when a building catches fire, in which there is a significant content of polystyrene foam, everything burns, even metal structures.
In turn, during the combustion of polystyrene, its thermal degradation occurs, during which a significant amount of substances hazardous to humans are released. Therefore, even in the Soviet Union, with a unified system of sanitary and chemical control of the use of polymeric materials, the Ministry of Health of the USSR banned the use of expanded polystyrene in construction.
In connection with the above, in Western Europe, 20 years ago, expanded polystyrene was completely removed from residential buildings. The main peaceful use of expanded polystyrene in northern Europe and Canada is for the insulation of road and railway tracks. To give the road durability, slabs of this material are added to the body of its “layer cake”. Moreover, not foamed, but extruded polystyrene foam (technology developed by BASF, Germany) is used, which has a rigid and durable shell. This makes it possible for expanded polystyrene not to be saturated with moisture, maintain its heat-insulating ability and prevent freezing of the roadway - which is the main reason for its rapid destruction. The use of expanded polystyrene in greenhouses is also effective, especially in the northern regions. Studies have shown that toxic STYRENE is not released into a humid environment, but remains in the Styrofoam without causing any harm. In addition, under a layer of sand, gravel or soil, the fire hazard of expanded styrene is out of the question. That's where the place of this material.
Fire hazard of polyurethane foams ("Isolation of a full set of chemical warfare agents")
Unlike expanded polystyrene, rigid polyurethane foam is an inert, toxic polymer with a neutral odor. For this reason, it is widely applied to food storage refrigerators. Polyurethane foam does not create toxic emissions that cause human disease or death.
But as a result of the combustion of polyurethane foams and polyisocyanurate foams, a mixture of low molecular weight thermal decomposition products and their combustion products is always formed. The composition of the mixture depends on temperature and oxygen access.
The process of dissociation of polyurethane foam into the original components - polyisocyanate and polyol - begins after heating the material to 170-200°C.
With prolonged exposure to high temperatures above 250 ° C, most thermosetting plastics, as well as rigid polyurethane foams, gradually decompose.
When the isocyanate component is heated above 300°C, it decomposes to form volatile polyureas (yellow smoke) in the case of flexible polyurethane foams or to non-volatile polycarbodimmides and polyureas in the case of rigid polyurethane foams and polyisocyanurate foams. Thermal decomposition of the polyisocyanate and polyol occurs.
At temperatures exceeding 300°C, the destruction of polyisocyanurate foam begins, which, unlike polyurethane foam, contains a more stable isocyanurate cycle. The temperature at which a sufficient amount of combustible decomposition products are formed, which can be ignited by flames, sparks or combustible surfaces, for rigid polyurethane foams from 320 ° C.
For rigid polyurethane foams based on special grades of polyisocyanate, the decomposition temperature with the release of combustible gases is in the range from 370 ° C to 420 ° C. In addition, during the decomposition of various polyurethane foams when heated to 450 ° C, the following compounds were identified: carbon dioxide (carbon dioxide), butane, tetrahydrofuran, dihydrofuran, butanedione, water, hydrocyanic (cyanic) acid and carbon monoxide (carbon monoxide).
Carbon monoxide (carbon monoxide, carbon monoxide, CO).
The main toxic component of the combustion products of polyurethane foams and polyisocyanurates at all stages of a fire, both at low and high temperatures, is carbon monoxide.
The natural level of CO in the air is 0.01 - 0.9 mg/m3, and on the highways of Russia, the average concentration of CO is from 6-57 mg/m3, exceeding the poisoning threshold. Carbon monoxide (carbon monoxide) is toxic, it has the ability to combine with blood hemoglobin 200-300 times faster than oxygen. The blood becomes unable to carry enough oxygen from the lungs to the tissues, and rapid and severe poisoning ensues.
At a content of 0.08% CO in the inhaled air, a person feels a headache, nausea, weakness and suffocation. At 1% concentration of carbon monoxide in the room after 1-2 minutes, it has a deadly effect. With an increase in CO concentration to 0.32%, paralysis and loss of consciousness occur (death occurs after 30 minutes). At a concentration above 1.2%, consciousness is lost after 2-3 breaths, a person dies in less than 3 minutes.
Hydrocyanic acid (cyanic acid, hydrogen cyanide, formic acid nitrile, HCN).
In the combustion products of polyurethane foams and polyisocyanurates, the presence of hydrocyanic acid is observed, the release of which is 10 times less than the content of carbon monoxide.
Hydrocyanic acid (hydrogen cyanide, hydrocyanic acid) (HCN) is a colorless transparent liquid with a boiling point of boiling point - +25.7°C. Due to its low boiling point, hydrocyanic acid is very volatile, especially in a fire. This is a very strong poison of general toxic action. It has a peculiar intoxicating smell, reminiscent of the smell of bitter almonds.
The average daily maximum permissible concentration (MAC) of hydrocyanic acid in the air of populated areas is 0.01 mg/m3; in the working premises of an industrial enterprise - 0.3 mg / m3. Acid concentrations below 50.0 mg/m3 are unsafe if inhaled for many hours and lead to poisoning. At 80 mg/m3, poisoning occurs regardless of exposure. If you stay in an atmosphere containing 100 mg/m3 for 15 minutes, this will lead to severe injuries, and more than 15 minutes - to death. Exposure to concentrations of 200 mg/m3 for 10 minutes and 300 mg/m3 for 5 minutes is also lethal. Both gaseous and liquid hydrocyanic acid are absorbed through the skin. Therefore, with a long stay in an atmosphere with a high concentration of acid without skin protection, even in a gas mask, there will be signs of poisoning as a result of resorption.
Among the products of thermal decomposition (destruction) of polyurethane foams containing polyethylene glycols, methane, ethane, propane, butane, ethylene oxide, formaldehyde, acetaldehyde, ethylene glycol, water and carbon monoxide are found. In addition to the listed substances, propylene, isobutylene, trichlorofluoromethane, acrolein, propanal, methylene chloride, and traces of other substances that do not contain nitrogen atoms were also found in the decomposition products of polyols.
If there is no external source of ignition, then the products of thermal decomposition ignite only at temperatures from 450 °C to 550 °C. When heated above 600 °C, the resulting polyureas and polycarbodimmides decompose with the release of a large number of low molecular weight volatile compounds, such as benzene, toluene, benzonitrile, and toluenenitrile. It was also shown that the aromatic ring of the listed nitrogen-containing compounds is split according to the law of chance with the formation of acrylonitrile, a large number of unsaturated compounds.
In a real fire, the products of thermal destruction actively burn with the formation of water, carbon dioxide and carbon monoxide, as well as nitrogen oxides.
When choosing such a heater, it is necessary to remember that: polyurethane foams and polyisocyanurates foams, in comparison with other organic materials, release a significant amount of toxic products when exposed to high temperatures.
But, unfortunately, in our country there are many organizations that “produce” polyurethane foam components in a handicraft way. Therefore, after some time runs decomposition of the material, thermophysical characteristics are an order of magnitude worse than those recommended, the concept of "durability" in this case is not applicable at all. As a rule, no flame retardant is added to this surrogate. Therefore, such "polyurethane foam" burns well with the release of a variety of chemical warfare chemicals.
There is no input control in construction. Works on thermal insulation of building structures mainly lie on the conscience of invited workers, most often guest workers.
In conclusion, we present data on the concentration of volatile toxic substances released during a fire and their impact.
table 2
| Name and chemical formula | Description of impact | Concentration | Symptoms |
| Carbon monoxide, carbon monoxide, CO | As a result of connection with blood hemoglobin, an inactive complex is formed - carboxyhemoglobin, which causes a violation of oxygen delivery to body tissues. It is released during the combustion of polymeric materials. The release is facilitated by slow burning and lack of oxygen. | 0.2-1% vol. | The death of a person for a period of 3 to 60 minutes. |
| Carbon dioxide, carbon dioxide, CO2 | It causes an increase in breathing and an increase in pulmonary ventilation, has a vasodilating effect, causes a shift in the pH of the blood, and also causes an increase in the level of adrenaline. | 12% vol. | Loss of consciousness, death within minutes. |
| 20% vol. | Immediate loss of consciousness and death. | ||
| Hydrogen chloride, hydrogen chloride, HCl | Reduces the possibility of human orientation: in contact with a wet eyeball, it turns into hydrochloric acid. It causes respiratory spasms, inflammatory edema and, as a result, impaired respiratory function. It is formed during the combustion of chlorine-containing polymers, especially PVC. | 2000-3000 mg/m3 | Lethal concentration at action within several minutes. |
| Hydrogen cyanide, (hydrogen cyanide, hydrocyanic acid), HCN | Causes a violation of tissue respiration due to the suppression of the activity of iron-containing enzymes responsible for the use of oxygen in oxidative processes. Causes paralysis of nerve centers. It is released during the combustion of nitrogen-containing materials (wool, polyacrylonitrile, polyurethane foam, paper-laminated plastics, polyamides, etc.) | 240-360 mg/m3 | Death within 5-10 minutes |
| 420-500 mg/m3 | A quick death | ||
| Hydrogen fluoride, (hydrogen fluoride, HF) | Causes the formation of ulcers on the mucous membranes of the eyes and respiratory tract, nosebleeds, spasm of the larynx and bronchi, damage to the central nervous system, liver. Cardiovascular insufficiency is observed. It is released during the combustion of fluorine-containing polymeric materials. | 45-135 mg/m3 | Dangerous to life after a few minutes of exposure |
| Nitrogen dioxide, NO2 | When released into the blood, nitrites and nitrates are formed, which convert oxyhemoglobin into methemoglobin, which causes oxygen deficiency in the body due to damage to the respiratory tract. It is assumed that during fires in residential buildings there are no conditions necessary for intense combustion. However, there is a known case of mass death of people in a clinical hospital due to the burning of x-ray film. | 510-760 mg/m3 | When inhaled, bronchopneumonia develops within 5 minutes. |
| 950 mg/m3 | Pulmonary edema | ||
| Ammonia, NH3 | It has a strong irritating and cauterizing effect on the mucous membranes. Causes profuse lacrimation and pain in the eyes, suffocation, severe coughing spells, dizziness, vomiting, swelling of the vocal cords and lungs. Formed by burning wool, silk, polyacrylonitrile, polyamide and polyurethane. | 375 mg/m3 | Permissible within 10 minutes |
| 1400 mg/m3 | Lethal concentration | ||
| Acrolein (acrylic aldehyde, CH2=CH-CHO) | Slight dizziness, flushing of blood to the head, nausea, vomiting, slow pulse, loss of consciousness, pulmonary edema. Sometimes there is severe dizziness and disorientation. Sources of vapor emission - polyethylene, polypropylene, wood, paper, oil products. | 13 mg/m3 | Portable no more than 1 min |
| 75-350 mg/m3 | Lethal concentration | ||
| Sulfur dioxide (sulfur dioxide, sulfur dioxide, SO2) | On the moist surface of the mucous membranes, they successively turn into sulphurous and sulfuric acid. Causes cough, nosebleeds, bronchospasm, disrupts metabolic processes, promotes the formation of methemoglobin in the blood, acts on the hematopoietic organs. It is released during the combustion of wool, felt, rubber, etc. | 250-500 mg/m3 | dangerous concentration |
| 1500-2000 mg/m3 | Lethal concentration on exposure for several minutes. | ||
| Hydrogen sulfide. H2S | Irritating to eyes and respiratory tract. Seizures, loss of consciousness. It is formed during the combustion of sulfur-containing materials. | 700 mg/m3 | severe poisoning |
| 1000 mg/m3 | Death within minutes | ||
| Smoke, steam-gas-aerosol complex | It contains solid particles of soot, liquid particles of resin, moisture, condensation aerosols that perform a transport function for toxic substances during breathing. In addition, smoke particles sorb oxygen on their surface, reducing its content in the gas phase. Large particles (> 2.5 microns) settle in the upper respiratory tract, causing mechanical and chemical irritation of the mucous membrane. Small particles penetrate the bronchioles and alveoli. Upon admission to in large numbers airway obstruction is possible. |
With the simultaneous entry of combustion products into the human body, a complex effect of joint exposure is observed, and an increase in temperature during a fire increases the sensitivity of the body to the toxic effects of harmful substances.
Over the past decade, the use of polyurethane foam for various thermal insulation in our country has increased by more than one or two times, but as much as five times! It's worth thinking about this.At the very peak of the popularity of this wonderful heat-insulating material, a large number of different myths began to appear regarding the environmental friendliness and safety of sprayed polyurethane foam insulation, both for human health and for environment.
In order to understand everything, namely, how safe and environmentally friendly this heat-insulating material is, first of all, you need to know what polyurethane foam itself is and what it consists of. And so everything is in order.
This material is similar in structure to ordinary soap foam, as it consists of isolated cells that contain gas. The difference compared to soap suds is that the cells of this material are the same size. The gas itself accounts for almost ninety-five percent of the total volume of polyurethane foam, and it is a heat insulator. And the remaining five percent is nothing but a solid polymer.
In the initial methods of manufacturing polyurethane foam, freon was used, but according to new laws, it is strictly forbidden to import it into our country and at present, absolutely environmentally friendly materials, such as soybeans, water, various vegetable oils. Because of this, it is often called eco-friendly thermal insulation not harmful to human health and the environment.
Perhaps you are wondering: “Does polyurethane foam emit any substances that are harmful, toxic to our health and the environment?”. And we will also give a clear explanation to this question.
Is polyurethane foam harmful?
Among the many different thermal insulation materials, polyurethane foam deservedly occupies one of the leading places. However, even mineral wool, which is considered fundamentally safe, releases formaldehyde, which is dangerous to health, which, as you may or may not know, is contained in the adhesive base and helps the mineral wool fibers to maintain their shape. It is also worth adding that polyurethane foam, unlike mineral wool, is not an allergen, therefore mineral wool is strictly forbidden to be used in children's and medical buildings. In such facilities, in most cases, polyurethane foam is used. By itself, polyurethane foam is not combustible and is not an allergen. This material has low thermal conductivity and even with a short-term local ignition, the smoldering process itself is completely excluded.At this time, the use of various highly volatile ether fractions in the manufacture of polyurethane foam is completely excluded. It does not contain asbestos, freon, formaldehyde and various other chemicals harmful to health and the environment. After the PU foam spraying process, no harmful substances are found in the room.
High-quality sprayed thermal insulation with polyurethane foam improves the microclimate of the treated room several times: humidity decreases, air leaks decrease, mold does not form, dust does not pass through. From the above, it follows that high-quality spraying with polyurethane foam contributes to twice the energy savings for space heating, which leads to saving natural resources and serves as a significant contribution to ecology and nature. These, so to speak, useful and unique properties of polyurethane foam make it one of the leaders among an infinite number of different polymers.
Currently, due to environmentally friendly properties and safety Sprayed thermal insulation with polyurethane foam is used more and more in industrial, residential and administrative buildings. On the this moment Over time, environmental requirements are becoming more stringent and important, so many experts are confident that thermal insulation by spraying polyurethane foam will still rapidly win back lost ground from those materials that are significantly inferior to it in these parameters.
From this we can say with great confidence that sprayed thermal insulation is the future! Make your choice together with the UyuTerm company in favor of an environmentally friendly, no harmful, modern, heat-insulating material - polyurethane foam!
