about protective films.

about protective films.

And again about protective films

The most economical solution

When choosing the type of glazing, one of the main factors for the user, in addition to reliability, quality and others, is the price he must pay for new, more durable and beautiful glass. Of the many possible options, the only correct solution seems to us to be the installation of protective self-adhesive films on the glass based on polyethylene terephthalate. This will not require replacing the glazing, and therefore, new high consumer properties will cost the buyer much less in this case.

The range of products presented by Solarex CJSC includes several dozen types of self-adhesive films that can impart a number of new qualities to glass. When choosing certain types of film, consumers are usually interested in whether the strength and other characteristics change over time at different temperatures and humidity. There is no doubt that the film will retain all its properties at room temperature and relative humidity of 50-60°. But how will it behave when installed on external glass in the cold winters of the Far North or the hot summers of the southern outskirts of Russia? This is worth telling in more detail.

The performance of Solarex film in various climatic conditions

All Solarex films available are made on a base of lavsan (polyethylene terephthalate), the physical and mechanical properties of which have a number of advantages over bases made of other polymers.

Such films can operate in the temperature range from -60 to +80° C, maintaining guaranteed strength characteristics. They withstand repeated freezing and defrosting, perfectly tolerate relative humidity of 100°o. Even in extreme operating conditions, their physical, mechanical and optical characteristics by the end of the warranty period remain virtually unchanged and the actual service life of the films is at least 15-20 years.

As for the strength characteristics of glass laminated with film, they can be measured precisely. Tests conducted at the Research Institute of Steel in February of this year show that 4 mm thick architectural glass with a 112 µm film installed on it can withstand an impact with an energy of 25.5 J, which is equal to the strength of 4-1-4 triplex. However, we understand that consumers are more interested in strength tests not by hitting an abstract ball in laboratory conditions, but by assessing the resistance of glass covered with films in real conditions.

Let's try to estimate what an intruder can do if he sets out to throw a grenade weighing 0.7 kg through a window into a room. A well-trained person, an athlete, with an optimal throwing angle of 45 degrees can give the thrown grenade an initial velocity of approximately 18.5 m/s.

Let's take into account the fact that a sport grenade throw is made with a running start, that is, the initial speed of the grenade also includes the speed of the athlete (about 9 m/s). The attacker, naturally, throws the grenade from a standing position, otherwise he simply will not hit the window. Subtracting this value, we get 8.4 m/s for throwing from a standing position. The attacker is not an athlete. His clothes will hinder him. In addition, there will be some distance between him and the window. Taking these factors into account, when the grenade comes into contact with the glass, one can hardly expect a speed of more than 8 m/s.

Therefore, the really expected impact energy will be 22.4 J.

As we can see, 4 mm thick glass with a film installed on it has the required margin of safety. The grenade will bounce off the glass with a 100% guarantee.

So, the film installed on the existing glazing does not require significant material costs for its modernization, and in terms of strength, the combination of glass and film is superior to triplex. Comments are unnecessary.

About two years ago, we wrote on the pages of this magazine about the need for a complete transition of industrial and civil construction to safety glazing. In many countries, such a transition has already been made, which is bearing fruit — injuries from glass fragments during natural and man-made disasters, as well as from human collisions with glass parts of building structures have decreased by 2-3 orders of magnitude. We hoped that with the introduction of GOST R 51136-98, safety glazing would be legalized in our country as well, that there would be appropriate reactions to this GOST from the State Construction Committee, the Ministry of Emergency Situations, the Ministry of Internal Affairs of Russia, and other regulatory organizations. However, the section «Safe Glass in Construction» has been moved to the recommended category, and there is no need to talk about how the recommendations are followed. But the lives and health of people are at stake.

We live in very troubling times. The explosions of apartment buildings in Moscow and other Russian cities, the recent Chechen events and the associated threats of mass terrorist attacks throughout Russia cannot be viewed as empty bravado. Urgent and adequate measures must be taken.

In this regard, we consider it necessary to tell in more detail what Solarex films can do to reduce the consequences of explosions.

So, an explosion has occurred. The zone of increased air pressure caused by it spreads as a shock wave, damaging people, buildings, and equipment. The vacuum that forms at the epicenter of the explosion after the shock wave has left is just as destructive and deadly. When the shock wave reaches the windows of the house, they are destroyed. The size of the destruction zone depends on the amount of energy in the shock wave, and this in turn is directly related to the power of the explosion. Thus, the intensity of destruction depends on the power of the explosion and the distance from its epicenter.

A shock wave that moves at high speed gives glass fragments enough energy to kill a person. There are frequent cases when glass fragments pierce cars and human bodies. If the windows were closed before the explosion, and the explosion was powerful, the glass breaks into tiny fragments. In this case, the shock wave literally sucks oxygen out of a person, which leads to difficulty breathing, and the person's lungs are stuffed with tiny fragments of glass. As a rule, this leads to death a few days after the explosion. Doctors face big problems in cases when glass fragments penetrate the human body. These fragments are transparent and indistinguishable in color from the organs they penetrated. They are also invisible during X-ray examination, since they absorb X-rays in the same way as human body tissue. All this makes medical care ineffective.

So, all factors of an explosion — shock wave, fragments, including from shattered glass, sudden changes in air pressure — are capable of causing significant harm to people's health, leading to destruction and material losses. How can protective films installed on glass withstand an explosion?

First of all, films withstand high mechanical loads without breaking, due to which most of the shock wave energy is absorbed. Thus, the front of increased air pressure spreads towards the building and pushes the glass into the room, where it eventually shatters into pieces. However, if a protective film is installed on the glass, it continues to absorb the shock wave energy and where unprotected glass breaks, the glass with the film remains intact — just as if it were at a significant distance from the explosion. In other words, the energy of the shock wave, capable of breaking unprotected glass, is completely insufficient to break the glass with the film installed on it. Even if the glass cracks, it still remains in the frame, its fragments do not come off the film and do not cause any harm to people's health or damage to property.

In cases where the glass does fly out of the frame, it folds together with the film, there is no scattering of fragments, and the damage is minimal. Statistics show that even in such cases at least 95° of the glass remains glued to the film. If a low air pressure zone occurs at the explosion site, the glass with the film can be pushed out, but the damage from this will be even more insignificant.

Thus, it can be stated that if protective films are installed on window panes, the risk to people and property in the event of explosions can be reduced to a minimum.

The author of the article states with full responsibility that the number of victims of the explosion in the shopping center on Manezhnaya Square in Moscow would have been 5-8 times less if the thinnest (56 microns) protective film had been installed on all glass surfaces — display cases, partitions, etc. The damage to buildings located in the immediate vicinity of houses blown up by terrorists in Moscow and other cities would have been reduced to practically zero if ordinary tinting films, rather than shockproof ones, had been applied to the window panes of these houses.

In our opinion, the threat of terrorist attacks must be responded to not only by the police switching to a special operating mode and improving the security of residential buildings and other facilities. A decision on the mass installation of protective self-adhesive films on glass structures is absolutely necessary.