Noise protection screens are the main type of noise reduction and creation of the comfortable living conditions.
Principle of noise protection screen
The screen creates an acoustic shadow zone. To create a sound wave barrier effect protected objects must be below this shadow (in a vertical projection). That is if we draw a line from the noise source to the top of the screen, the protected object should not be up to it.
Noise protection screens (fences) are divided according to the principle of action into:
The screen should be high and long enough, so that only a small part of the sound wave diffracted around it. If the screen is not long enough for the buildings, which are close to its ends, the noise reduction is less than 5 dB (A). A rule of thumb - the screen must be of such length that the distance between the receiver and the screen end was 4 times greater than the length of the perpendicular from the receiver to the screen. Another version of this rule states that the angle between the perpendicular from the receiver to the screen and a line from the receiver to the end of the screen should be at least 80°. Sometimes the area and geometry of the motorway have no room to accommodate the screen of the proper length. In these cases, screen designers can offer to build a screen with the ends bent inward.