Active lightning protection - is an engineering and technical system, the main task of which is, in case of a dangerous thunderstorm,to "artificially"accept and safely drain the lightning current to the ground, advancing its "natural" development and thereby protecting a larger area in comparison with conventional methods.
To understand the operation principle of active lightning protection, below see some of the bases of the theory of lightning development and organization of lightning protection systems.
What is lightning and external lightning protection system
Linear lightning - is an atmospheric discharge, arising due to the growth of strain in the space between the clouds and the ground (and / or objects located on it).
The dynamics of the lightning development can be described as follows:
- In most cases, the discharge begins to develop from the cloud - a downward leader is being formed;
- In some tim, an upward leader starts towards it from the ground surface;
- At a time when two leaders meet, there is a major atmospheric discharge.
External lightning protection is aimed to save the object to be protected from destruction due to the direct lightning strike. Its main aim - is to accept and safely divert lightning currents into the ground..
Any lightning protection system operates according to the rule of generating a counter leader, providing its development from the lightning rod device with a certain probability. All elements of the system, as well as the materials used are chosen so that even during the flow of lightning currents thereon, the integrity of the system and of the protected facility won't be broken.
The operating principle of active lightning protection
The main difference of active lightning protection (ALP) from traditional lightning protection devices is the presence of an active lightning rod that responds to the increase of the electromagnetic field that arises when a storm front is approaching. The capacitors included into the ALP, are charged from the voltage induced by this field to the antennas of the device. Upon reaching of 12-14 kV on the capacitors, there happens the breakdown of arresters and formation of short fuses high-voltage pulse (more than 200 kW), the polarity of which is reciprocal to the polarity of the front. This pulse, advancing the formation of a "natural" leader initiates the "artificial" upward leader that develops at a much faster rate and to a greater distance, multiply increasing the protection zone of the lightning rod.
The use of the active lightning protection system is particularly justified in cases where due to the specifics of the protected object, it is impossible to use any conventional lightning protection design, such as seaport, on construction site or public places. The companies RST and GALMAR even guarded the Pope! An active lightning rod was mounted in 1998 in Gliwice, which protected the believers at the solemn liturgy with the participation of John Paul II.
Furthermore, the ALP system allows to keep the aesthetic appearance of the object to be protected, without overloading it with a massive lightning protection structure, that in turn leads to the reduction of material costs and required volume of assembling works.
Advantages of active lightning protection:
- protection zone of an active lightning rod greatly exceeds the protection zone of the conventional (passive) air terminal of a similar height.
- high level of protection *provided by the design of ALP, minimizes the probability of a lightning breakthrough and hitting of the protected object.
- active lightning rod - is a stand-alone device, that does not require connection to any power source.
- the device is activated only in case of an approaching storm front and presence of a real risk of a lightning strike.
* levels of ALP protection are defined in accordance with NF C 17-102 "Protection of structures and open areas against lightning using early streamer emission air terminals"
Determination of the security level of the object
Selection of active lightning protection system should start from determination of protection level that is necessary to be provided for a specific object.
In accordance with standard NF C 17-102 "Protection of structures and open areas against lightning using early streamer emission air terminals",protection level is determined on the base of the following conditions:
- substitutional work area of collection
Nominal territory, from which a lightning strike into an object may happen. It depends on the size and shape of the object.
- the ratio of the expected and admitted frequency of lightning strikes into objects
It characterizes the real importance of installation of lightning protection system.
- location of the object
Probability of hitting an isolated facility located on a hill is more than the object located in a restrained urban conditions.
- hazards arising in case of a lightning strike into an object
depend on several factors: flammability of walls / roofing, cost of the object, number of people on-site and possibility of their evacuation, environmental consequences of a strike. The required protection level should be determined by taking into account all these hazards.
|Initial data. Equations||Calculations||Result|
**Ng max= 2NgWhere Ng [strike / year / km2] - the average density of lightning strikes in the area, where the object is located.
|Determination of object location||тХи╨▒1|
|surrounded by trees or other objects of equal or exceeding its height||0,25|
|surrounded by objects lower than it||0,5|
|there are no other objects at the distance of 3 * H from the object||1|
|isolated object, located on a small hill or cusp||2|
|low, no risk of fire||0,5|
|standard cost or low fire risk||1|
|standard cost or high risk of fire||2|
|exceptional cost or an extremely high risk of fire (explosions)||3|
|Number of people on- site||тХи╨▒4|
|difficult conditions of evacuation of people or risk of panic||3|
|Consequences of lightning strike||тХи╨▒5|
|A room, that does not require continuous maintenance, no danger for the environment||1|
|A room, requiring continuous maintenance, no danger for the environment||5|
|E > 0,95||level I|
|0,80 < E ≤ 0,95||level II|
|0 < E ≤ 0,80||level III|
Selection of components
After defining the required level of security by the manner described above and knowing the height at which you plan to install an active lightning rod, you can start to choose a particular model of an active lightning rod.
Do not forget that for the organization of the external lightning protection system you will also need other components from sections "external lightning protection" and "grounding". An approximate list is presented on the right of the page.
If you have any difficulty in calculating or selecting the components, you can always ask our technical center for assistance.
GALACTIVE active lightning rods with advanced streamer emission are presented in two versions:
1. GALACTIVE 1 (product item GL-20015) - is composed of two radiation electrodes;
2. GALACTIVE 2 (product item GL-20016) - is composed of three radiation electrodes, provides greater protection zone compared to GALACTIVE
GALACTIVE 1 and 2 lightning rods are fully autonomous and do not require connection to any power source.
The device is activated only in the event of an approaching storm front if there is a real risk of a lightning strike.
GL-20015/ GL-20016 Weight: 2,9 kg Diameter: 200 mm Height: 320 mm
Detailed information on choosing a particular GALACTIVE model is shown on a separate page.
A traditional vertical air termination device as a two-meter(GL-21101G) or four-meter (GL-21103G) mast that comes with a tip screwed on.
For the installation of GALACTIVE from the mast, it is necessary to unscrew the sharp tip and place an active lightning rod on its place.
The mast is made of stainless steel in the form of a tube with the wall thickness of 2 mm.
GL-21101G GL-21103G Weight: 5 kg 10 kg Height: 2000 mm 4000 mm Diameter of the lightning rod: 35 mm 35 mm Thickness of the wall: 2 mm 2 mm
HolderGL-21202(the set consists of two units) allows you to fix the vertical lightning rod (mast) GL-21101G /GL-21103Gto the chimney or air channel.
The holder is fixed by ten anchors in the wall (five anchors per each), which provides very high mechanical strength of the structure.
Made of stainless steel.
Bolts, washers and nuts are made of stainless steel.
GL-21202 Thickness of the "claw": 6 mm Width of the "claws" (at the extreme points) 515 mm Height of the "claws" (at the extreme points) 190 mm The distance from the air terminal to the wall 190 mm
It is possible to use the same holder designed for the installation in the wall. It is possible to read the description on a separate page.
Clamp to the air-terminal mast GL-21101G / for down conductors (stainless steel)
The clamp GL-20022 allows you to connect the wire electrode of a diameter of 8 mm to the air terminal mast GL-21101G / GL-21103G.
Allows to fix two conductors (from different sides).
Made of stainless steel.
Bolts, washers and nuts are made of stainless steel.
Gl-20022 Diameter of the down conductor: 8 mm Weight: 0,2 kg Length: 62 mm Width: 30 mm Height (including the bolt) 100 mm
Copper-bonded GL-11149 is made of rolled steel with electrolytic copper plating with a purity of 99.9% and not less than 0.070 mm thick, that forms molecular and indissoluble connection with the steel.
The wire with the diameter of 8 mm (area of cross-section is ╤В╨Р╨Ы╤В╨Р╨Ы50 mm²) is used as down conductors of external lightning protection
GL-11149 Weight of 1 meter: 0,41 kg Diameter: 8 mm Area of cross-section: 50 mm2
Clamps for fixation of down conductor to different types of roof / facade
Clamps - fixing elements for fixing down conductors to the surface and / or connection of each other.
Galmar clamps are presented in two versions:
1. Clamps made of pure copper;
2. clamps made of steel with the tight double coating - of zinc and powder paint. These clamps possess remarkable features: high corrosion resistance and resistance to various harmful factors (including mechanical protection), very attractive appearance, low cost.
See a complete list of fasteners and choose the clamps required to implement your system of active lightning protection, on a separate page.
Modular grounding ZANDZ and GALMAR
GALMAR and ZANDZ grounding rods are made of steel coated with a protective copper coating not less than 0.250 mm thick, which provides a guaranteed lifetime of the device up to 100 years.
The design of the rods, which can be interconnected and immersed in the soil to a depth of 40 meters, allows to achieve low ground resistance on a small area. The installation is carried out by one person without the use of construction and specialized machinery.
ZANDZ modular grounding can be purchased in the form of ready-made packages and as separate components.
To see the detailed information of a modular grounding technolog, visit a separate page.