High frequency – Protective measures against wireless radiation in everyday life (Part 5)

29.07.2020

Let me briefly explain the decibel value. Every shielding material, whether stainless steel mesh, or a fleece or shielding paint, has a decibel value. This decibel value indicates the damping ratio of this material. It is best to have a table at hand so that you can convert decibel values into percent. Because then you can multiply the radiation exposure you have by this permeability percentage and so obtain the residual permeability, in other words: what you finally are exposed to after all. A small example: Assuming we have a radiation exposure of 100,000 µW/m2 , we can decide whether we want a stainless steel mesh or a shielding fabric. This stainless steel mesh has a shielding value of 50 dB, this fleece here has a shielding value of 80 dB. Looking at the table now: 50 dB has a permeability of 0.001 %. If we now multiply these 100,000 µW/m2 by these 0.001 %, we get exactly a residual permeability of 1 µW/m2. That would be the ideal value which should prevail in a bedroom, minimum value one must say,. If we want to shield even better with this fleece, we can do the calculation again. If we have a shielding value of 80 dB, we have a permeability in percent of 0.000001. If we multiply this amount again by these 100,000 µW/m2, we get a residual permeability of 0.001 µW/m2. This would be an excellent value. Then you can make up your mind, what do I want? It also matters if my radiation level is even higher. Do I have more than 100,000 µW/m2? And on the basis of this you can then select your shielding material. I will now tell you about the various shielding materials and their intended use. We begin with the color. This is a paint, acrylic dispersion, with graphite in it. The graphite shields the radiation. This paint is very good, it is very easy to apply. You can paint the walls and it can be normally overpainted with any customary paint. This is very positive about this color. The value to mention here is: with a single coat of paint you have a decibel value of 37 dB and with two coats you get 44 dB. Also available are shielding tissues, which are fabrics that are glued to the walls as under-wallpaper and which are later covered with a wallpaper. However, these must be applied with an electrically conductive glue. There are also shielding fleeces, like this one here. These materials are very positive, they have very high decibel values. You can also lay them twice, then the values are even higher, and even better. Also very simple about it is that you can use it, for example, in drywall constructions, which means that if you are building plaster stands, you can tack it between the plasterboards or simply lay it in, glue it in, whatever you want. It can also be laid under the floor covering, simply laid in loosely. This also gives very, very good shielding values. There are various solutions for windows, for example curtain fabrics. These fabrics from the Y-Shield brand are available in many different designs with a variety of base materials and various metals in them. Very positive about curtain fabrics is that you can use them well in rented apartments where you cannot just install a mesh yourself. Curtain fabrics are available with various decibel values, in a variety of base materials and metals contained therein. They can also be used in two layers, which increases the decibel value and provides better shielding. Also a good alternative for screening windows are stainless steel mesh like this one here. There are several types, for example this one is more loosely braided, which means it has a lower decibel value. One so finely woven is better in decibels and it also makes a difference on the see-through, how well you see through the fabrics. Very advantageous is that the fabrics are made of stainless steel and therefore rustproof, they can be used outside in the weather. They do not rust, which means you can also use them in a sub-roof if you want to shield the roof Also a very valuable alternative for shielding the windows – here is your own little solution. These are steel profiles from the do-it-yourself store, decorative magnets, from the same store, and here is this stainless steel mesh: If you stick onto the façade these steel profiles around the reveal of the window, you can cut a mesh that is the right size and fix it here just like that with these magnets. It is very easy to remove again and the other advantage is that you have really shielded a continuous surface if you have also painted the facade. I hope I have helped you with these different application examples and also with these measuring instruments so that you know how to handle them. The documents with the various specifications about decibel values and the whole decibel conversion table can be downloaded below this program.

from Ramon

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