Does the film transmit ultraviolet rays. Does glass transmit ultraviolet light? Where does ultraviolet radiation come from?

There were times when tanned skin was considered a sign of low birth, and noble ladies tried to protect their faces and hands from the sun's rays in order to maintain an aristocratic pallor. Later, the attitude towards tanning has changed - it has become an indispensable attribute of a healthy and successful person. Today, despite the ongoing debate about the benefits and harms of insolation, the bronze skin tone is still at the peak of popularity. But not everyone has the opportunity to visit the beach or a solarium, and in this regard, many are interested in whether it is possible to sunbathe through a window glass, sitting, for example, on a glazed loggia or attic heated by the sun. According to the site http://onwomen.ru

Probably, every professional driver or just a person who spends a long time behind the wheel of a car noticed that his hands and face become covered with a light tan over time. The same applies to office workers who are forced to sit at an uncurtained window for the entire shift. On their faces, you can often find traces of sunburn even in winter. And if a person is not a frequenter of solariums and does not make a daily promenade through the parks, then this phenomenon cannot be explained otherwise than by tanning through glass. So does glass transmit ultraviolet light and is it possible to tan through a window? Let's figure it out.

The nature of tanning

In order to answer the question of whether it is possible to get a tan through ordinary window glass in a car or on a loggia, you need to understand exactly how the process of darkening of the skin takes place and what factors influence it. First of all, it should be noted that sunburn is nothing more than a protective reaction of the skin to solar radiation. Under the influence of ultraviolet light, the cells of the epidermis (melanocytes) begin to produce the substance melanin (dark pigment), due to which the skin acquires a bronze tint. The higher the concentration of melanin in the upper layers of the dermis, the more intense the tan.

However, not all UV rays cause such a reaction, but only those in a very narrow wavelength range. Ultraviolet rays are conventionally divided into three types:

• A-rays (long wavelength)- are practically not delayed by the atmosphere and freely reach the earth's surface. Such radiation is considered the safest for the human body, since it does not activate the synthesis of melanin. All it can do is cause a slight darkening of the skin, and then only with prolonged exposure. However, with excessive insolation with long-wave rays, collagen fibers are destroyed and the skin becomes dehydrated, as a result of which it begins to age faster. And some people are allergic to the sun because of A-rays. Long-wave radiation easily overcomes the thickness of window glass and leads to gradual fading of wallpaper, furniture surfaces and carpets, but it is impossible to get a full tan with its help.
• B-rays (medium wave)- linger in the atmosphere and reach the Earth's surface only partially. This type of radiation has a direct effect on the synthesis of melanin in skin cells and contributes to the appearance of a quick tan. And with its intense exposure to the skin, burns of varying degrees occur. B-rays cannot penetrate through ordinary window glass.
• C-rays (shortwave)- represent a great danger to all living organisms, but, fortunately, they are almost completely neutralized by the atmosphere, before reaching the surface of the Earth. Such radiation can only be encountered high in the mountains, however, even there its effect is extremely weakened. Physicists distinguish another type of ultraviolet radiation - extreme, for which the term "vacuum" is often used due to the fact that waves of this range are completely absorbed by the Earth's atmosphere and do not fall to the earth's surface.

UV is radiation with wavelengths from 400 nm to 10 nm. It is divided into 4 ranges:
A: 400-315 nm
B: 315-280nm
C: 280-100 nm
Extreme: 121-10 nm.

Different materials have different transparency to ultraviolet rays depending on the wavelength. For the extreme range, even air is opaque! The window pane allows band A to pass through, but does not pass the other 3.
You can verify this by looking at the graph.

The graph is verified by a simple experiment. We shine a 365 nm UV LED through ordinary glass with a thickness of 6 mm on an invisible inscription that glows only under ultraviolet light.

There is no noticeable decrease in brightness. You can take glass several times thicker, but the inscription will continue to glow, ultraviolet passes very well!

Glass transmission of 400-315 nm is especially important to consider when choosing high-quality sunglasses, because most of the ultraviolet present on the street passes through a glass lens without a protective layer: in Moscow from 301 nm, in temperate latitudes from 295 nm, in the world from 286 nm .

If you say that air does not transmit ultraviolet, it will be a half-truth, just like saying that glass does not transmit UV. You should always mention the specific ultraviolet range so that such dangerous half-myths do not appear.

• Can you tan through glass?

  Whether it is possible to get a tan through window glass or not depends on what properties it has. The fact is that glasses come in different types, each of which is affected by UV rays in different ways. Thus, organic glass has a high transmission capacity, which allows the passage of the entire spectrum of solar radiation. The same applies to quartz glass, which is used in tanning lamps and room disinfection devices. Ordinary glass, used in residential premises and cars, transmits only long-wave rays of type A, and it is impossible to sunbathe through it. Another thing, if you replace it with plexiglass. Then it will be possible to sunbathe and enjoy a beautiful tan almost all year round.

  Although sometimes there are cases when a person spends some time under the sun's rays passing through the window, and then finds a light tan on the exposed skin. Of course, he is in full confidence that he got tanned precisely by insolation through the glass. But it is not so. There is a very simple explanation for this phenomenon: the change in shade in this case occurs as a result of the activation of a small amount of the residual pigment (melanin) produced under the influence of type B ultraviolet radiation, located in the skin cells. As a rule, such a “tan” is temporary, that is, it quickly disappears. In a word, in order to get a full-fledged tan, you must either visit a solarium or regularly take sunbaths, and it will not work to change the natural skin tone towards a darker one through ordinary window or car glass.

• Is it necessary to defend?

Worrying about whether it is possible to get a tan through glass is only for those people who have very sensitive skin and a predisposition to the appearance of age spots.

They are advised to use special means with a minimum degree of protection (SPF) at all times. Apply such cosmetics should be mainly on the face, neck and décolleté. However, it is still not worth protecting yourself too actively from ultraviolet, especially long-wave, because the sun's rays in moderation are very useful and even necessary for the normal functioning of the human body.

The pages of this information resource have already noted the need to protect products made of polyethylene, in particular semi-finished products (polyethylene rods, sheets, plates, etc.) made of polyethylene of various grades, as well as other materials of the polyolefin family, from the harmful effects of UV radiation during operation outdoor products.

The harmful effect of UV - radiation is expressed in a change in the color of the material (fading), as well as in a change in its mechanical properties - the material becomes brittle and cracks, even without mechanical stress.

It should be noted that these processes (fading and change in mechanical properties) are not related to each other - fading characterizes, first of all, the durability of dyes used in the production of materials, and therefore the loss of the original color of the product does not always mean a change in the mechanical properties of the material.

As noted above, to make polyolefins resistant to UV radiation, special UV stabilizers (HALS - inhibitors) are introduced into their composition during the production process.

In general, it can be said that the resistance of a material to UV - radiation, and, consequently, the service life of products, depends on the amount and effectiveness of the UV stabilizers used, as well as on the intensity of UV - radiation - at higher latitudes, the intensity of UV - radiation is lower, than in the lower ones. Additionally, the intensity of UV - radiation can enhance, for example, its reflection from the water surface.

The combination of stabilizers and dyes added to the material can also have a significant impact on product life, for example carbon black dye added to polyethylene products is itself a good UV stabilizer, so the service life of black polyethylene products is the longest. .

Leading manufacturers of engineering thermoplastics regularly test their materials to determine the effect of UV radiation on their properties. In general, it can be said that the target indicator for the period during which there should not be a significant change in the properties of materials is 10 years.

However, taking into account the fact that, as noted above, the intensity of UV radiation for different climatic zones is different, for places with high radiation intensity, the actually achievable value of this indicator can be much lower.

On the other hand, for products containing a soot-based dye, the service life can be much longer - up to 20 years on average, without significant changes in the properties of the material.

Separately, it is worth dwelling on the issue of fading of the material. This effect can be observed to a greater or lesser extent, depending on the intensity of UV - radiation and the durability of the dyes used. At the same time, the resistance of recently used organic dyes, as a rule, is significantly lower than the resistance of dyes based on heavy metals (for example, cadmium). Therefore, not always more modern materials are more resistant to fading.

The question of whether linoleum is harmful to health, I was asked quite often. The opinion about the toxicity and allergenicity of this flooring is widespread, and therefore, when choosing materials for interior decoration, many are skeptical of linoleum. Well, if there are small children in the house, then the level of suspicion must be multiplied by at least two.

In fact, a significant part of the claims about the dangers of this material for health are either greatly exaggerated or refer to low-quality varieties. And yet, it is simply necessary to figure out where is the truth and where is fiction. That is why I analyzed the main sources describing the harm of linoleum, and I suggest that you familiarize yourself with my conclusions.

Material analysis

Natural and synthetic coatings

Before you understand whether linoleum is harmful or not, you need to specify in advance what material we are talking about. As anyone who has even a little experience with flooring knows, linoleums are different, but in this aspect, the division into natural and synthetic coatings will be most relevant.

It is convenient to compare them using the table:

As you can see, in natural linoleum, in principle, there are no components that can cause health problems. The coating is non-toxic, does not emit volatile substances, and contains practically no synthetic components.

Therefore, if the price (rather high, it must be admitted - from 1000 rubles per square or more) does not bother you, then buy it. If you are still limited in funds, or you need a more moisture-resistant and wear-resistant material, then you will have to put up with some of the disadvantages of synthetic linoleum.

Potential threats from linoleum

So, back to our thesis that the harmfulness of linoleum mainly concerns its synthetic varieties.

What are the potential threats?

1. Polyvinyl chloride, which acts as a binder (a replacement for linseed oil, cheaper and more accessible), is itself almost completely inert. If it is not taken as food, then its toxicity will be zero, so the harm from it is still a myth.

PVC does release toxic chlorine gases when burned.
But I think that this situation is already beyond the scope of the issue under discussion: if linoleum is on fire, then in any case it poses a threat.
On the other hand, polyvinyl chloride itself ignites very reluctantly, in addition, where necessary, the instruction recommends laying special fire-resistant linoleum.

1. The reinforcing material - fiberglass - also does not contain volatile substances that can have a negative impact on health. There is nothing to fear here either.

1. The main source of danger are additives - stabilizers and plasticizers. They are introduced into the composition of PVC so that it is both durable and elastic. Some manufacturers use cheap raw materials with low environmental friendliness, and therefore, immediately after laying, the material actively emits toxic volatile phenols. For an adult, staying in a room with "fresh" linoleum can cost a headache, and even provoke poisoning in a baby.

1. Pigments should also be included here: if cheap paint was used for decoration, and even the manufacturer saved on the thickness of the abradable layer, then after two or three years of operation, particles of coloring substances will begin to enter the atmosphere. They may not cause any particular harm to health, but they can provoke an allergic reaction in a person with a predisposition.
2. Another threat is associated with the decomposition of polymers under the influence of ultraviolet radiation. If filtering additives were not introduced into the polyurethane coating to create a protective layer, then under bright sunlight (for example, in a living room with large windows), the coating will begin to decompose, and some of the decomposition products will enter the atmosphere.

1. Finally, you should not lay commercial and semi-commercial varieties of coatings in the house (especially bedrooms and children's rooms). Quite different requirements are put forward for their composition, so that even in high-quality models, the content of potentially hazardous components can be high.

Glue as a harmful factor

Another factor that causes harm from linoleum, and which is often forgotten, is glue.

Its influence should be taken into account for the following reasons:

1. Many themselves contain large amounts of volatile toxins. Of course, linoleum manufacturers do not recommend using such mixtures for installation, but quite often craftsmen (either self-taught or simply not responsible enough workers) work with what they have.

1. The active components of the adhesive, even if they are not toxic in themselves, can react with polyurethane, causing both its decomposition and the dissolution of additives (plasticizers, stabilizers, pigments). In addition to reducing the strength and service life of the coating, the result is not very useful “chemistry” getting into the air.
2. Particular attention should be paid to the choice of glue if the linoleum is laid on a warm floor: when heated, chemical reactions are activated, and the risk of getting at least an unpleasant odor, and at the most serious intoxication, increases significantly.

Briefly summarizing, I still note: unlike common situations, most of the statements about the dangers of linoleum are not myths. They simply do not concern all products on the market, but only products from the economy segment: trying to reduce costs, material manufacturers sometimes violate a number of standards.

What can be done, I will tell below!

How to make the floor as safe as possible?

Since we figured out that a significant part of the talk about the dangers of linoleum is not a myth, and at least has a rational justification, then it’s worth considering what can be done with this information.

It is quite possible to protect yourself, and I recommend following these rules (they are quite simple):

1. We choose only high-quality coatings. Linoleum must have a certificate of compliance with sanitary standards. If there is no such certificate, then even the lowest price should not become an argument in favor of the purchase.

For children's rooms, we buy only specialized coatings, to which much more stringent requirements are put forward.

1. Smell the roll before buying. A strong chemical odor is a sign of high levels of toxins. Of course, any linoleum will “smell”, but you can easily identify frankly substandard options.

1. After installation, ventilate the room well.. It is desirable that at least five to seven days pass between finishing the floors and settling in: during this period, the concentration of toxins in the air will just decrease.
2. And when doing the installation with our own hands, and when contacting professional finishers, we pay attention to the adhesive composition used. Let you have to overpay a little, but it's better to take really high-quality safe glue.

1. When cleaning, we use only those detergents that do not destroy the floor covering..
2. Timely replacement of linoleum, without waiting for its wear due to the complete destruction of the abradable layer under the influence of pedestrian load and ultraviolet radiation.

Conclusion

Having figured out how harmful linoleum is, and having understood which factors are dangerous, it will be quite simple to prevent unpleasant consequences. The recommendations I have given, based on practical experience, and the video in this article and comments in which you can ask me questions on all aspects of the topic will help you with this.

The steel structure is protected from corrosion by priming followed by painting. But aluminum does not need protection. For greater reliability, experts recommend an anodized aluminum profile reinforced with a steel rod.

Wood is also used. Compared to metal, wooden elements are much more massive. In addition, they need a number of protective measures: painting, treatment with antiseptics and flame retardants.

The plastic profile offered on the market is more suitable for temporary structures. In our climatic conditions, it quickly becomes unusable. So that it does not bend from a strong gust of wind, it is better to choose a profile reinforced with a metal rod.

The main surface of the walls and roof is formed by translucent structures fixed on the frame. They use glass, film and plastic.
Glass lets through 90% of the sunlight and retains heat well: even in frosty weather in a glazed greenhouse, the temperature will be 4 ° C higher than the outside. Its main disadvantages are fragility and significant weight. For greenhouses use glass 3 mm thick. The glazing of the metal frame is sealed with a rubber sealant, and the wooden frame is sealed with wooden glazing beads.
Acrylic (plexiglass)- light colorless material that can withstand significant mechanical stress (which is important in heavy snowfalls), transmits ultraviolet rays and is not inferior in transparency to glass.
Polycarbonate- a polymer material that is 250 times stronger and 6 times lighter than glass. It has high strength, heat and fire resistance, as well as low thermal conductivity. It transmits not much less light than clear glass. Can be sewn up polycarbonate the entire frame and do not dismantle the coating for the winter for many years. This material is monolithic and cellular. From the first, elements of both flat and curvilinear shapes are made. Such products are quite rigid and do not require a supporting frame. However, they are relatively expensive, so flat roofs are covered with cellular polycarbonate. Due to its structure, it has high thermal insulation characteristics. And its low weight allows you to install light load-bearing structures. Sheets with a thickness of at least 8 mm are used as roofing material. For walls, you can choose thinner sheets. The surface of polycarbonate is sensitive to mechanical influences.
Polyvinyl chloride (PVC) produced in the form of corrugated sheets. It is characterized by high mechanical and impact resistance, resistance to ultraviolet radiation, durability, flexibility at temperatures from -40 to +65 °C. Transparent colorless PVC sheets transmit 82% of the light, but do not transmit ultraviolet, therefore, specially treated PVC materials are used for greenhouses that transmit UV radiation necessary for photosynthesis.
Polymer film elastic, transparent and easy to install. It withstands frosts down to -20 ° C, but does not tolerate sudden changes in temperature. The polyethylene film transmits 80% of visible and ultraviolet rays, is resistant to alkalis and acids, impermeable to water and steam. Its disadvantage is high thermal permeability, up to 90%. Under the action of ultraviolet and air, the film ages, its translucency decreases, and by the end of the season the material is destroyed. The film panel is glued with phenol, formaldehyde, formic acid, welded with a soldering iron or iron. When docking, it is laid so that the edge of one sheet overlaps the edge of the other by 10-15 mm. A strip of cellophane is applied to the place of the seam.
PVC film It transmits 90% of visible and up to 80% of UV rays, but almost does not transmit infrared rays, due to which the greenhouses cool slightly at night. The service life of this material is two to three seasons.
Ethylene vinyl acetate copolymer film characterized by increased strength, elasticity and light resistance. It is wind and puncture resistant. Serves up to three years.
Rolled fiberglass made on the basis of polyester resins reinforced with fiberglass. It is characterized by high strength, reliability and poorly transmits thermal radiation. Supplied in rolls 90 cm wide. Pieces are joined with essential resins. The service life of rolled fiberglass is four years.

Polymer plastic is characterized by strength, practicality, durability and ease of installation. At the same time, the service life of the material depends on its technical characteristics. Today we will consider a topic that is so relevant for many builders and gardeners, how does polycarbonate transmit ultraviolet rays.

UV protection

Polycarbonate is considered one of the most durable and strong polymers. However, this material is destroyed by exposure to sunlight. Thus, polymer plastic sheets used for sheathing greenhouse structures, garden greenhouses, gazebos, verandas, terraces and other open buildings quickly become unusable. After 2–3 years from the moment the building was erected, the sheathing completely loses its original physical properties and qualities.

Polycarbonate is UV resistant, making it ideal for greenhouse cladding.

Manufacturers of polymer plastic have found a way to increase the level of wear resistance of the material. Polycarbonate began to be made with a special ultraviolet coating. The protective layer was some kind of stabilizer-granules that were added to the material during primary processing. Unfortunately, the use of this kind of technology requires a significant investment. Accordingly, the cost of building material increases.

Currently, polymer plastic is made with a thin ultraviolet coating, which is called UV protection.

There are two ways to apply the UV layer:

1. Spraying. The surface of the polymer plastic panel is covered with a thin layer of a special solution that looks like industrial paint. This method has significant drawbacks. During transportation, installation and operation of the web, the protective layer is erased, as a result of which the polymer becomes unusable. Applied in the form of spraying, UV protection is unstable to atmospheric precipitation and mechanical influences from the outside.
2. Extrusion protection from direct sunlight. A special layer that prevents the destruction of the polymer is implanted into the surface of the polycarbonate panel. The canvas is resistant to physical and chemical damage, as well as various atmospheric phenomena. The service life of polycarbonate with extrusion sun protection is 20–25 years.

Video "Protection of polycarbonate from ultraviolet radiation"

From this video you will learn what is the UV protection of cellular polycarbonate.

Selection rules

Many are interested in how to determine the presence of a UV coating on the surface of a sheet of polymer plastic.

Responsible manufacturers stick a protective film on polycarbonate sheets. Transparent colorless polyethylene indicates that there is no sun protection on this side of the panel. Transparent color film is the first reference for the presence of a protective ultraviolet layer.

• name and type of building material;
• technical characteristics of polycarbonate;
• recommendations on the features of loading, unloading, transportation, installation and maintenance of the polymer;
• information about the manufacturer.

Often, the marking is applied to colored polyethylene, which helps to avoid scratches, dents, chips and cracks on the outside of the polycarbonate.

If the film is missing, turn the polymer towards the sun. The UV coated side reflects the characteristic purple reflections in the sun.

When choosing a building material, including polymer plastic, you need to focus on the technical properties and qualities of the material.

Polycarbonate with UV protection is a guarantee of durability and strength of the building sheathing.