Polyethylene film allows ultraviolet rays to pass through. Greenhouse materials

To answer this question, let’s understand the nature of such a phenomenon as ultraviolet radiation, and the nature of a material such as plexiglass.

Until we get to detailed characteristics, we will answer the question - Does plexiglass transmit ultraviolet radiation? Yes, he lets him through!

Ultraviolet radiation is rays that are located just beyond the visible spectrum in wavelength. The wavelength range for ultraviolet is 10-400 nm. The range of 10-200 nm is called vacuum or “far”, since rays with this wavelength are present exclusively in outer space and are absorbed by the planet's atmosphere. The remaining part of the range is called “near” ultraviolet, which is divided into 3 categories of radiation:

wavelength 200-290 nm - short wavelength;
wavelength 290-350 nm - medium wave;
wavelength 350-400 nm - long wavelength.

Each type of ultraviolet radiation produces different impact on living organisms. Short-wave radiation is the most high-energy radiation; it damages biomolecules and causes DNA destruction. Medium wave radiation causes burns to the skin of humans; plants tolerate short-term irradiation without consequences, but over a long period of time, vital functions are suppressed and die.

Long-wavelength is practically harmless to the vital functions of the human body, safe and beneficial for plants. The short-wave ultraviolet range and part of the mid-wave range are absorbed by our “protective armor” - ozone layer. Part of the medium-wave radiation range and the entire long-wave range, i.e., reaches the surface of the planet, the habitat of living beings and plants. spectrum of beneficial rays and those not harmful during short-term irradiation.

Plexiglas is a chemical synthetic polymer structure of methyl methacrylate, which is transparent plastic. Light transmission is slightly lower than that of ordinary silicate glass, easy to machine, and light weight. Plexiglas is not resistant to certain solvents - acetone, benzene and alcohols. Manufactured based on standard chemical composition. The differences between brands and manufacturers lie in the imparting of specific properties: impact resistance, heat resistance, UV protection, etc.

Standard plexiglass allows ultraviolet light to pass through. Its radiation is characterized by transmittance:

no more than 1%, for a wavelength of 350 nm;
not less than 70%, for a wavelength of 400 nm.

Those. plexiglass transmits only long-wave radiation, at the very edge of the wavelength range, which is the safest and most useful for living organisms.

It is worth noting that plexiglass has low resistance to mechanical stress. Over time, if abrasive particles come into contact with it during the cleaning process, the surface is damaged, the glass becomes dull and reduces its ability to transmit both visible light and ultraviolet radiation.

Polymer plastic is characterized by strength, practicality, durability and ease of installation. In this case, the service life of the material depends on its technical characteristics. Today we will look at a topic that is so relevant for many builders and gardeners: does polycarbonate allow ultraviolet rays to pass through?

UV protection

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

Polycarbonate does not transmit UV rays, which makes it ideal material 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 produced with a special ultraviolet coating. The protective layer consisted of some stabilizer granules that were added to the material during primary processing. Unfortunately, the use of this type of technology requires significant investment. The cost increases accordingly building material.

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

There are two ways to apply the ultraviolet layer:

Spraying. The surface of the polymer plastic panel is covered thin layer a special solution that looks like industrial paint. This method It has significant shortcomings. During transportation, installation and operation of the canvas protective layer is erased, as a result of which the polymer becomes unusable. Applied in the form of spraying, UV protection is not resistant to precipitation and mechanical influences from the outside.
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 fabric is resistant to physical and chemical damage, as well as various atmospheric conditions. The service life of polycarbonate with extruded solar protection is 20–25 years.

Video “Protecting polycarbonate from ultraviolet radiation”

From this video you will learn what kind of ultraviolet protection there is. cellular polycarbonate.

Selection rules

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

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

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

Some types of polycarbonate sheets have enhanced protection from
ultraviolet radiation, they should be selected depending on the purpose

Often the markings are applied to colored polyethylene, which helps to avoid scratches, dents, chips and cracks outside polycarbonate.

If there is no film, turn the polymer towards the sun. The UV-coated side reflects the characteristic purple reflections of the sun.

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

Polycarbonate with ultraviolet protection is a guarantee of durability and strength of the building's cladding.

May 28, 2016
Specialization: professional in the field of construction and renovation ( full cycle carrying out finishing works, both internal and external, from sewerage to electrical and finishing works), installation of window structures. Hobbies: see the column "SPECIALIZATION AND SKILLS"

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

In fact Substantial part Claims about the health hazards of this material are either greatly exaggerated or refer to low-quality varieties. And yet, it is simply necessary to figure out where is truth and where is fiction. That's why I analyzed the main sources describing the dangers of linoleum, and I invite you to familiarize yourself with the conclusions I made.

Material analysis

Natural and synthetic coatings

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

It is convenient to compare them using the table:

Natural linoleum

Synthetic linoleum

The basis of the material is jute fabric - burlap of rare weave;
jute is impregnated with a composition based on linseed oil (linum oleum, hence, by the way, the name of the material) with the addition of turpentine (also mostly natural);
wood flour, lime flour, resins, pigments, etc. are used as fillers.

the base of the roll is foamed PVC, which is responsible for compensating for unevenness of the base, providing heat and sound insulation;
a reinforcing layer can be laid on top of the base - fiberglass, which gives the coating strength and elasticity;
on top there is a decorative layer of polyvinyl chloride with a pattern applied to it;
An abrasive material can be applied over the pattern - a transparent coating based on polyurethane or the same PVC.

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 virtually no synthetic components.

Therefore, if the price (quite high, I must admit - 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, let's return to our thesis that the harmfulness of linoleum mainly concerns its synthetic varieties.

What are the potential threats?

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

When PVC burns, it does release toxic chlorine gases.
But I think that this situation already goes beyond the scope of the issue under discussion: if linoleum burns, then in any case it poses a threat.
On the other hand, polyvinyl chloride itself is very reluctant to ignite; in addition, where necessary, the instructions recommend laying special fire-resistant linoleum.

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.

The main source of danger are additives – stabilizers and plasticizers. They are added to PVC to make it both durable and elastic. Some manufacturers use cheap raw materials with low environmental friendliness, and therefore, immediately after installation, the material actively releases toxic volatile phenols. For an adult, staying in a room with “fresh” linoleum can cause a headache, and for a baby it can even provoke poisoning.

Pigments should also be included here: if cheap paint was used for decoration, and the manufacturer saved on the thickness of the abraded layer, then after two or three years of operation the particles coloring matter will begin to enter the atmosphere. They may not cause any particular harm to health, but they may well provoke an allergic reaction in a person with a predisposition.
Another threat is associated with the decomposition of polymers under the influence of ultraviolet radiation. If filter 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.

Finally, you should not install commercial and semi-commercial types of coatings in your home (especially bedrooms and children's rooms). There are completely different requirements for their composition, so even in quality models the content of potentially hazardous components may 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:

Many themselves contain a large number 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.

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

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

What can be done, I will tell you below!

How to make the floor as safe as possible?

Since we have figured out that much of the talk about the dangers of linoleum is not a myth, and at least has a rational basis, then it is worth thinking about what can be done with this information.

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

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

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

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

After installation, ventilate the room well. It is advisable that at least five to seven days pass between finishing the floors and moving in: during this period the concentration of toxins in the air will decrease.
Both when performing installation yourself and when contacting professional finishers, we pay attention to the used adhesive composition. You might have to overpay a little, but it’s better to get really high-quality safe glue.

When cleaning we use only those detergents that do not destroy the floor covering.
We replace linoleum in a timely manner, without waiting for its wear due to the complete destruction of the abraded layer under the influence of pedestrian load and ultraviolet radiation.

Conclusion

Having figured out why linoleum is harmful, and having understood exactly what factors pose a danger, prevent unpleasant consequences it will be quite simple. 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 raised.

Summer residents who decided to use polycarbonate for the construction of their suburban area greenhouse or greenhouse for growing vegetables, the question is: “Does polycarbonate transmit ultraviolet rays?” The emergence of such a question is not unfounded, because the harm that ultraviolet radiation has on plants is known. In order to be able to answer the question that has arisen and make a final decision on the use of a polymer, you will need to have information about the positive and negative aspects of the material.

Material advantages

Regardless of whether polycarbonate transmits ultraviolet rays or not, it has a huge amount undoubted advantages. These included the following material properties:

Low price for the material. Polycarbonate does not require constant and large financial investments in caring for itself during its operation.
The structure of the thermoplastic is such that even the assembled material can be easily disassembled for storage or reassembled.
Aesthetic qualities that are present due to the production of polymer in a wide color palette.
High strength index. Thermoplastic is able to withstand high mechanical loads (shock or pressure from a high mass of something).
Possibility to produce independently with polymer installation work. The material lends itself well to mechanical processing (drilling, cutting), so working with it does not require extra effort or special skills.
Speed of installation work with the material.
Excellent flexibility of thermoplastic panels, allowing them to be used even in complex structures.
Light weight. Polycarbonate is about fifteen times lighter than glass, and this makes it possible, when using the material for greenhouses or greenhouses, not to install a foundation for the structure.
The transparency of colored sheets of material reaches fifty percent, and for transparent plates this figure reaches eighty-five percent. The duration of operation does not affect the decrease in the transmittance coefficient of light rays.
Good light dispersion is present due to the presence of a protective film on the surface of the panels, which contributes to the dispersion of sunlight and protection from penetration into inner part placing ultraviolet radiation emanating from the sun from contact with polycarbonate. This property allows the rays of the Sun to be distributed evenly between plants if the polymer is used in greenhouses or greenhouses.
Thermal conductivity. This property varies depending on the thickness of the slabs. The thicker the panel, the lower the thermal conductivity and vice versa.
Fire safety. The material does not quickly ignite and has self-extinguishing properties. The polymer begins to melt only under the influence of a temperature of 570 degrees Celsius, and does not release gases into the air that contain poison for living organisms.
If the material is nevertheless subjected to significant impacts and receives mechanical damage, then it will not crumble into small particles, as if glass and its edges will not be so sharp as to have the ability to cause a cut human body from careless contact.

Flaws

Polycarbonate with and without UV protection, in addition to its advantages, also has a few disadvantages. These include the following material properties:

a decrease in the ability to transmit light - this is possible if the cells of the edges of the panels are covered with ordinary tape or not covered at all, or were washed with solutions containing solvents, chlorine, or abrasive particles;
deformation of the material may occur if the profile and sheets are manufactured by different manufacturers and do not adhere tightly to each other or the linear expansion of the slabs was not taken into account;
bends under the weight of snow or from strong gusts of wind - this is possible if the material used is of poor quality or its thickness does not correspond to the climatic conditions of a given region, or the installation work was carried out with errors.

Features of polycarbonate with and without ultraviolet protection

Knowing the answer to the question: “Does polycarbonate transmit ultraviolet rays?” you can make a final decision on whether to use thermoplastic panels in the construction of the greenhouse.

Good to know: After all, it is known that ultraviolet radiation that penetrates inside the greenhouse and is in the range of 390 nanometers can harm plants.

Polycarbonate is able to block ultraviolet radiation if its outer surface is covered with a special film having a thickness of 20-70 microns. Without a protective film, ultraviolet radiation will penetrate through polymer boards. Material with protective film does not turn yellow and can be used without transmitting ultraviolet radiation for ten years.

Video about polycarbonate protection from ultraviolet radiation

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 their aristocratic pallor. Later, the attitude towards tanning changed - it became an indispensable attribute of a healthy and successful person. Today, despite the ongoing controversy regarding the benefits and harms of sun exposure, bronze skin tone is still at the peak of popularity. But not everyone has the opportunity to visit the beach or solarium, and in this regard, many are interested in whether it is possible to tan through window glass, sitting, for example, on a sun-warmed glass loggia or attic. According to the website http://onwomen.ru

Probably every professional driver or just a person driving long time while driving a car, he noticed that his hands and face became lightly tanned over time. The same applies to office workers who are forced to sit all the time. work shift at the uncurtained window. You can often find traces of tanning on their faces even in winter period. And if a person is not a regular at solariums and does not take a daily promenade through parks, then this phenomenon cannot be explained otherwise than by tanning through glass. So does glass allow ultraviolet light to pass through and is it possible to tan through the 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 the skin occurs and what factors influence it. First of all, it should be noted that tanning is nothing more than a protective reaction of the skin to solar radiation. Under the influence of ultraviolet light, epidermal cells (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 upper layers dermis, the more intense the tan.

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

A-rays (long wave)- are practically not delayed by the atmosphere and easily reach earth's surface. This type of radiation is considered the safest for human body, since it does not activate melanin synthesis. All it can do is cause slight darkening of the skin, and then only with prolonged exposure. However, with excessive insolation by long-wave rays, collagen fibers are destroyed and the skin is dehydrated, as a result of which it begins to age faster. And some people develop an allergy to the sun precisely 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 obtain a full tan with its help.
B-rays (medium wave)- linger in the atmosphere and reach the Earth's surface only partially. This type radiation has a direct effect on the synthesis of melanin in skin cells and contributes to the appearance of a quick tan. And with intense exposure to it, burns occur on the skin. varying degrees. B-rays cannot penetrate through ordinary window glass.
C-rays (short wave)- pose a huge danger to all living organisms, but, fortunately, they are almost completely neutralized by the atmosphere, without reaching the surface of the Earth. You can only encounter such radiation high in the mountains, but even there its effect is extremely weakened. Physicists identify 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 reach 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: 315-280 nm
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! Window glass allows range A to pass through, but does not allow the other 3 to pass through.
You can verify this by looking at the graph.

Schedule is being checked a simple experiment. Through ordinary glass 6 mm thick, we shine a 365 nm UV LED onto 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 radiation passes through very well!

Glass transmission of 400-315 nm is especially important to consider when choosing high-quality sunglasses, because glass passes through a glass lens without a protective layer. most of ultraviolet radiation present on the street: 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 radiation, it will be a half-truth, just like saying that glass does not transmit UV radiation. You should always mention the specific ultraviolet range so that such dangerous half-myths do not appear.

Can you tan through glass?

Whether you can get a tan through window glass or not directly depends on what properties it has. The fact is that glass can be different types, each of which is affected differently by UV rays. Thus, organic glass has a high throughput, which allows the passage of the entire spectrum of solar radiation. The same applies to quartz glass, which is used in solarium lamps and in devices for disinfecting rooms. Ordinary glass, used in residential premises and cars, transmits only long-wavelength rays of type A, and it is impossible to get sunburned through it. It's another matter if you replace it with plexiglass. Then it will be possible to accept sunbathing and enjoy beautiful tan almost all year round.

Although sometimes there are cases when a person spends some time under the sun's rays passing through a window, and then discovers open areas skin light tan. Of course, he is fully confident 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 residual pigment (melanin) produced under the influence of ultraviolet type B, located in 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 need to either visit a solarium or regularly take sunbathing, and it will not be possible to change the natural skin tone towards a darker one through ordinary window or car glass.

Do you need to defend yourself?

Only those people who have very sensitive skin and a predisposition to age spots should worry about whether it is possible to get a tan through glass.

It is recommended to use it constantly by special means with a minimum degree of protection (SPF). Such cosmetics should be applied mainly to the face, neck and décolleté. However, it is still not worth protecting yourself too actively from ultraviolet radiation, especially long-wave radiation, because Sun rays in moderation, they are very useful and even necessary for the normal functioning of the human body.