Air Termination System
air terminal to receive direct lightning strike on Mvrdhfazt structures are installed, they can be one or a combination of the following types: 1. simple bars (Rods) 2. The suspension wires connected (Stretched wire) 3. reticulated conductors (Meshed Conductor) 4. Active Lightning (Early streamer Emission)
Methods of attracting lightning conductors installed in the air terminal
Installation methods of attracting lightning conductor air terminals in the system: 1. The protection angle method (Protective angle method)2-way mesh (Meshed Conductor method) 3-way ball rolling (Rolling Sphere method)
Protective angle method
In the protective radius rod length and protection class in accordance with the table below.
Meshed Conductor method
To protect smooth surfaces, conductor networking that cover the entire surface of the roof, the best way to protect their interest level. This method is the conventional method Faraday cage. A) air terminal conductors must be installed in the following points:- Corners and sharp edges roof - On the roof ridge - On top of the slopes Note: wide horizontal and sloped roofing gridding method is appropriate. This method could be used to protect structures exposed to sparks lateral side surfaces (Side Flashing), are used. B) a network of conductors to different levels of data protection should be stated (according to) higher. C) network conductors should be implemented in such a way that at least a dual track for lightning current transmission (down on the conductor) terminals into their land. D) facilities-based metal on the surface protection, the network should air terminal conductors, are protruding.
It is clear from the table above as a protected class (LPL I) that is sensitive to protecting mesh size is smaller and larger mesh sizes less protection Hrchqdrhsasyt to be.
Rolling Sphere method
This method can be used for structures with irregular geometry that is significantly different height levels should be used. In this method the rolling "ball rolling" on the outside of the building from all directions and finding points of contact with the ball, building, installation guides air terminal (Air Termination) are identified. In this way, parts of the building that are in contact with the trackball Qrarnmy, air terminal is not protected and require no installation guide.Radius of the rolling sphere is proportional to the level of protection is as follows: 1. a protected class (LPL I) radius of the rolling balls 20 meters 2. Class II protection (LPL II) balls rolling radius of 30 m 3. protection class III (LPL III) rolling sphere radius 45 m 4-class four-protection (LPL IV) balls rolling radius of 60 m For structures taller than the radius of the "ball rolling" There is a possibility of lightning to the sides of buildings. However, the likelihood of conflict is low and the bulk of the lightning discharges on high structures, the highs, the corners and edges of the structure is done. 20 percent of high altitude elevated structures, are prone to lightning at an altitude of more than 60 meters should be 20% Dasht.lza end side surface structures under protection.