UV protection
Polycarbonate is considered one of the strongest and strongest polymers. However, this material degrades when exposed to sunlight. So, sheets of polymer plastic used for cladding greenhouse structures, garden greenhouses, gazebos, verandas, terraces and other open buildings quickly deteriorate. After 2–3 years from the moment the building was erected, the cladding completely loses its original physical properties and qualities.
Polycarbonate is UV-resistant, making it ideal for greenhouse sheathing
This is interesting: polycarbonate gazebos.
Polymer plastics manufacturers have found a way to improve the material's wear resistance. Polycarbonate began to be produced with a special ultraviolet coating. The protective layer was a kind of stabilizer-granules, which were added to the material during primary processing. Unfortunately, the use of this kind of technology requires a significant investment. Accordingly, the cost of the building material rises.
Currently, polymer plastic is manufactured with a thin ultraviolet coating, which is called UV protection.
There are two ways to apply the UV layer:
- Spraying. The surface of the polymer plastic panel is covered with a thin layer of a special solution, which looks like an 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 not resistant to atmospheric 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 canvas is resistant to physical and chemical damage, as well as to various weather conditions. The service life of polycarbonate with extrusion sun protection is 20-25 years.
What you need to know about protective properties
Why is it necessary to make sure that there is a protective layer on the sheets of the purchased material? It is necessary to know that polycarbonate without protective elements under the influence of the sun color quickly degrades. This does not imply its complete destruction, but turbidity and the appearance of microcracks in this case are guaranteed. The continued use of such material will be limited.
When buying material, the issue of security should be given sufficient attention. And this must be done for a number of reasons.
Firstly, sellers of the material may not focus on whether the UV protection of polycarbonate is applied to the material. Secondly, there are different ways of applying protection, which differ from each other.
And clarification of the applied method for the purchased material is one of the main questions of the buyer.
There are the following main differences between the two methods of providing ultraviolet protection:
- applying a protective layer by fusing a thin film on one side of the polycarbonate panel;
- the addition of a special substance called an ultraviolet stabilizer, which provides UV protection even at the stage of polycarbonate production.
If in the first case it is possible to visually verify whether the film has been applied, then the introduction of a protective substance into the mixture cannot be controlled. And cases when the declared properties were only declared, unfortunately, are not uncommon.One of the possible ways to protect yourself from counterfeiting is to buy polycarbonate panels from a trusted manufacturer, while not succumbing to the temptation to save a little on the purchase.
Among the possible control signs, whether the protection of polycarbonate from ultraviolet radiation has actually been established, one can single out the following points for oneself:
- In the case of applying a special protective film, the manufacturer indicates the installation of a special UV filter. In this case, there will be information on the orientation of the sheet when installed in the direction of the sun's rays.
- When using a special composition in the mixture to impart protective functions, the manufacturer does not always indicate the order in which the sheet is installed. In this regard, panels are often installed incorrectly.
Do not consider a protective film for transporting materials as a protective layer against UV rays.
It should be noted that even in the case of not providing high-quality protection of polycarbonate from UV radiation, a certain amount may retain the material itself. But this is clearly not enough as the expected effect. This minimal protection allows you to preserve the appearance and quality of the material only at the stage of storage and transportation. But in the future, with active use, the sun's rays will do their job.
Video about UV protection of polycarbonate
/ How to recognize UV protected polycarbonate
Today, almost all summer residents prefer greenhouses made of polycarbonate ... This material is gradually replacing plastic film and glass and takes a strong leadership position. However, as the saying goes, not all polycarbonate is "equally useful." In connection with the growth of consumer demand, an increase in the number of low-quality products can also be observed. And we are talking, first of all, about the protection of polycarbonate from ultraviolet radiation.
A range of polycarbonate glazing sheets are installed using dry or wet glazing systems where they can be used for both glazing and double glazing applications. Of course, maintaining the recommended separation between the glazing sheets will prevent touching in high temperature or high humidity environments. Important installation procedure.
Protection in bulk
To prevent incompatibility problems, use only recommended sealants. Occasionally, a glazing sheet can be subjected to high stress, which requires low moduli and high performance elastomers. The correct rib grip and expansion allowance must be carefully selected. These tools ensure that the surface is smooth and free of any notches or chips. Both flaps and prime must be clean. In case the process involves replacing old glazing sheets, the old protrusions and sealants must be removed. Use only recommended cutting tools. ... Wind load performance; Polycarbonates, which are used as glazing applications, are exposed to harsh environments such as hail, temperature fluctuations, and high speed winds.
Almost all consumers claim that their products have this protection, but it is rather difficult to understand whether this is really so, and the whole point is in the specifics of production. There are two options for providing polycarbonate with UV protection:
the application of a thin transparent film on one of the two surfaces of the polycarbonate sheet; the introduction of protection at the level of preparation of raw materials for the manufacture of sheets (that is, the protection is in the structure of the plastic itself).
Most of these factors are unpredictable and it is for this reason that factors such as wind performance need to be analyzed.Extension surcharge; although polycarbonates are dimensionally stable, they can expand, and it is for this reason that manufacturers provide recommended expansion allowances.
Service process; cleaning is the most basic maintenance procedure and should be done periodically to ensure that the polycarbonate glass sheet remains in good condition. The manufacturer will always recommend cleaning agents that are compatible with polycarbonate sheets. Use a soft cloth as polycarbonate is sensitive to scratches.
As it becomes clear, in both cases, this protection does not manifest itself in any way, therefore, it is difficult to distinguish material made using different technologies. And the need to distinguish is very important, since the second option with the introduction of protection into plastic structures is not so good - not all ultraviolet rays in this case are reflected from the surface of the sheet, passing through it. In the case of covering the sheet with a film, 100% protection is provided.
So when buying cellular polycarbonate, it is important to know for sure whether there is protection at all and what technology was used for its implementation.
For this reason, the use of abrasive cleaners is never recommended for cleaning. In addition to these, the technical information of the polycarbonate glazing sheet is an important document. It is because of this that the end user determines the type of glazing sheet used.
The installation process can be straightforward if you're a professional, however hiring a professional company may be the only option for those new to polycarbonates. Choosing a product is a complex process and in most cases it is almost impossible to get a product that is 100% perfect.
Construction mistakes when using cellular polycarbonate
All construction errors can be roughly divided into design errors and errors associated with the incorrect use of the material. Let us dwell in more detail on the errors associated with the incorrect use of the sheet.
Mistake # 1. The sheet is fixed to the sun by the side that does not contain surface UV protection. As a result, the leaf will turn yellow. The advice in this case is simple: do not remove the protective film with the markings before starting the installation. Otherwise, you can simply confuse the sides, because the presence or absence of UV protection by the eye cannot be determined.
It is for this reason that it is used in a number of applications such as roof construction, greenhouse construction, awnings, digital media, automobiles, sports safety, medical devices and many more. To meet these application requirements, they are available in different grades such as corrugated, textured and multi-walled polycarbonate sheets.
For optimal performance, the polycarbonate selection process is an essential process where users need to analyze every single aspect in a product datasheet. It can be used as an ideal replacement for a range of technical materials.
Mistake # 2. Special thermal washers are not used. Simple self-tapping screws can damage the sheet during thermal expansion, and dirt will accumulate in places of damage. Special washers are required in order to close the mounting hole from moisture and dirt and prevent them from entering the cells.
Mistake # 3 ... The ends of the cellular polycarbonate sheet are not closed (or not properly closed). If the ends are not closed, then the sheet becomes dirty, loses its appearance and light transmitting properties. There is a second option: the ends are closed "tightly" and the condensate formed in the honeycomb as a result of temperature changes does not come out. It is optimal to close the ends with a special perforated tape, and then a profile, which provide protection against dust ingress, but at the same time does not prevent moisture from escaping.
Influence of ultraviolet radiation
Do you want more daylight that does not come exclusively to the rooms through the windows? Need more sun, less shade and dark corners on your terrace? Then light panels are the right partner for you. The lightweight plates are transparent single-layer plates that are made of durable plastic and can be embedded directly into roofs.
Our light panels are not only easy to install, but can also be used in many areas. They are found, for example, in commercial buildings, on hall rooftops, or in the private sector as a roof or terrace canopy. The shape of the light plates is corrugated or trapezoidal. This creates a special stability that will serve you for many years. Buy a roof that gives you shelter and sun at a great price.
Mistake number 4. Incorrect use of the sheet class. All sheets of cellular polycarbonate are divided into classes: sheets for greenhouses (4 and 6 mm) and sheets for construction (from 8 mm). For example, you can often find that in the construction of stop complexes, a sheet with a thickness of 4 mm is used, moreover, a lightweight one. Such a sheet may not withstand the snow load, and people may be injured as a result of such a construction error. The same applies to translucent roofs and small architectural forms.
Terrace shelter with light panels
Applications for lightweight panels in a commercial area are hall roofs made of trapezoidal sheet, corrugated sheet or fiber cement boards, in private spaces, terraces and conservatories. The light-paneled terrace shelter not only protects your valuable garden furniture, barbecues, etc. from wind and weather, but also allows you to stop your garden or grill in case of rain. This extends the valuable gardening season by several weeks. And be honest; Nothing is more beautiful than spending free time outdoors.
Material advantages
Regardless of whether polycarbonate transmits ultraviolet rays or not, it has a huge number of undoubted advantages. These include the following material properties:
Low price for the material. Polycarbonate does not require constant and large financial investments in personal care 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 thanks to the production of polymer in a wide color palette.
High strength index. Thermoplastic is able to withstand a high mechanical load (shock or under pressure of a high mass of something).
The ability to carry out independent assembly work with polymer. The material lends itself well to machining (drilling, cutting), so working with it does not require extra effort or special skills.
The speed of implementation of installation work with the material.
Excellent flexibility of thermoplastic panels, allowing them to be used even in complex structures.
Low weight. Polycarbonate is about fifteen times lighter than glass, and this makes it possible, during the use of 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 coefficient of permeability of light rays.
Good light diffusion is present due to the presence of a protective film on the surface of the panels, which helps to scatter the sun's rays and protect against the penetration of ultraviolet radiation from the sun into the interior of the room from contact with polycarbonate. This property allows you to evenly distribute the rays of the Sun between plants if the polymer is used in greenhouses or greenhouses.
Thermal conductivity.This property varies with the thickness of the slabs. The thicker the panel, the lower the thermal conductivity and vice versa.
Fire safety. The material is non-flammable and self-extinguishing
The polymer begins to melt only under the influence of a temperature of 570 degrees Celsius, while it does not emit gases into the air that contain poison for living organisms.
If the material has nevertheless been subjected to significant impact and received mechanical damage, then it will not crumble into small particles, as if the glass and its edges will not be so sharp as to have the ability to cut the human body from careless contact.
disadvantages
Polycarbonate with and without UV protection, in addition to advantages, also has a small number of 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 pasted over with ordinary tape or not at all, or were washed with solutions containing solvents, chlorine, abrasive particles;
deformation of the material can occur if the profile and sheets are made by different manufacturers and do not adhere tightly to each other, or the linear expansion of the plates has not been taken into account;
sags under the weight of snow or from strong influence of 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 the given region, or the installation work was performed with errors.
End care
There are frequent cases when the ends of cellular polycarbonate bloom from moisture. Not many people know that it is better not to think about solving the problem after the fact, but to think about it even when buying material.
In a greenhouse covered with polycarbonate, the honeycomb of the material is turned towards the ground, so that not only moisture evaporating from the ground gets into it, but also dust, grass spores and insects. This creates an environment conducive to plastic flowering. You can be saved from this if you heed our advice:
- It is best to cover the ends of the plastic with a special hermo or punched tape, which allows moisture that gets inside the material to calmly go out, not letting it go further. This tape prevents dirt from entering the cells. To significantly increase the service life of the tape, its protection by the end profile will help;
- The ends can be coated with silicone gel. This method is relatively cheap, but if moisture gets into the panel, it will not be able to get out of it;
- The fastest and cheapest option would be to seal the ends with ordinary tape.
Let's sum up
Savings are not always appropriate. If you want to get a high-quality design that will serve you for more than one year, then choose a quality product and do not pursue cheapness.
How to deal with moisture inside the cells?
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Monthly: 08/07/2018
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Technical implementation
The shorter the wavelength, the more difficult it is to manufacture LEDs. Serial production of UVC LEDs for widespread use only began in the second half of the 2010s. Initially, they were developed as part of an international project to provide quality drinking water to the poorest countries in Africa. Compact LED water disinfection units can be powered by a battery, an individual wind turbine, or directly from a small solar panel when germicidal lamps require mains power or an inverter.Now they are trying to use these developments for the disinfection of air and surfaces in rooms.
For UVC LEDs, semiconductors with an increased band gap are used. At the time of this writing, the most common material for such LEDs was aluminum-doped gallium nitride (AlGaN). For example, LEDs based on it are produced by the California Eastern Lab (CEL). The advantage of AlGaN is the possibility of using already well-developed technological processes for the production of light sources. But this material also has disadvantages. It is characterized by a high level of crystal lattice defects, which reduces the efficiency. Another problem is the emission wavelength of 275 nm, which does not coincide with the optimal value.
Seoul Viosys was the first in the world to test its UVC LEDs on the COVID-19 virus. According to a company press release published on March 3, 2020, the virus was eliminated with a 90% efficiency.
As an example, let's take CL7003C2 - the most powerful UVC LED ever produced by CEL. The operating current is 600 mA at a forward voltage of 5.2 V. In this case, the radiation power is 30 mW. That is, as a result, we get an efficiency of about 1%. At the same time, the efficiency of a quartz lamp is 10-15%, and that of a bactericidal lamp is 35-50%. At the same time, the wholesale price for the LED is $ 109 per piece.
Everlight has also announced its 30mW UVC LED. Data on operating current and forward voltage have not yet been published, but indirectly, at a wavelength of 280 nm, it can be assumed that the same AlGaN technology is used. Also, 275 nm LEDs are manufactured by Seoul Viosys, a subsidiary of Seoul Semiconductor. The radiation power is up to 50 mW, the efficiency is about 1%.
Everlight UV LED with protective quartz glass
Aluminum nitride (AlN) is more promising as a material for UVC. It has less frequent crystal structure defects than AlGaN, which leads to a higher efficiency. This direction is being developed by the Klaran company. Its KL265-50U-SM-WD LED emits 60 mW of radiation with an average wavelength of 265 nm. The efficiency reaches 2%. Prices for these LEDs have not yet been announced.
Where to buy cellular polycarbonate for greenhouses?
By its nature, polycarbonate is not resistant to ultraviolet rays (UV), therefore, to ensure the durability of polycarbonate sheets, manufacturers cover them with a protective UV layer and introduce special additives into the polymer mass.
The second threat to polycarbonate sheets is ordinary dust that gets into the mass during production. The smallest dust particles, possibly even invisible to the human eye, can cause serious "burns" of the sheets and lead to a reduction in the service life of the material.
An analogy can be drawn to the melting of snow in spring. Dirty snow melts faster, as the grains of sand in the snow mass intensively absorb solar heat. So it is with polycarbonate: when heated in the sun, dust particles trapped in the polymer mass at the production site literally burn the polycarbonate from the inside.
As a result, the sheet "opens", bursts, gradually loses its aesthetic appearance, load-bearing capacity and tightness. Since cellular polycarbonate sheets are mostly used to create structures on the street (for the construction of greenhouses, awnings and canopies, translucent roofs, etc.) ) it is very important to carefully choose a supplier who, already at the production stage, will be able to ensure the durability of the consumer properties of its products. Including - cleanliness of production
7 rules for installing cellular polycarbonate
with my own hands
Rule 1
Colored, of course, looks more attractive, but it transmits much less light and, in the end, the plants simply will not have enough sun.
Rule 3
By the way, the calculation of the strength of the lathing of the supporting structure of the greenhouse or greenhouse will also depend on the thickness of the sheets of cellular polycarbonate so that it can withstand wind and snow loads.
Therefore, having chosen the polycarbonate you need, try to adhere to the size of the battens recommended in the installation instructions.
Rule 5
Since polycarbonate has a fairly large coefficient of thermal expansion, the hole for self-tapping screws must be made of a slightly larger diameter than a self-tapping screw.Fasteners must be started from the edge of the sheet, stepping back about 5 cm; the distance between the fasteners is not more than 30 cm.
Never fasten polycarbonate with nails - this will only break the integrity of the sheet and will inevitably lead to its destruction. Also, according to the rules, it is unacceptable to overlap the sheets - keep this in mind!
Rule 6
- tapes installed at the ends of the sheets will become their reliable protection and will not let dirt, dust and insects inside;
- and the profile must be installed over the tape on all free ends of the material.
Rule 7
quality material
Given the variety of cellular polycarbonate presented on the market today, I want to pay special attention to its quality.