Presently, there are 2 methods of Lightning Protection System being adopted in India. These are:
1) Conventional Mesh / Franklin Rod System:
In this method, a large number of Franklin rods and the strips are to be installed on the terrace and connected to the earth for the purpose of lightning protecti
2) Early Streamer Emission System:
In this method, generally one ESE lightning rod will be installed on the terrace and connected to the earth for the purpose of Lightning Protection.
In comparison, the ESE lightning rods are active systems. Here, either one or a very small number of lightning rods to be used (for the same area) to provide the highest degree of protection. A detailed comparison between conventional systems and ESE systems can be furnished on request.
The accepted standard world wide (more than 100 countries all over the world) for the lightning rods working on ESE principle is the French standard NFC 17102 and the Spanish standard UNE 21186.
No, the ESE rod does not unnecessarily attract the lightning strikes from surrounding areas. The Nimbus is designed to capture all lightning strikes within the area intended/ designed to be protected only and not from the surrounding areas.
The Nimbus lightning rod can only protect the structure and the people from the direct impact to the light strike. The damage to equipments housed inside the structure occurs because of the transient voltage surges caused by a lightning strike. The Nimbus lightning rod does not offer any protection against these surges.The equipment housed inside the structure will have to be protected , by installing a separate Surge Protection System.
A lightning discharge counter (supplied optionally) will record all the instances of lightning strikes captured by the NIMBUS Lightning Rod. Hence, by installing a lightning discharger counter, the exact number of lightning strikes captured by the Nimbus can be known
All the components used in the Nimbus lightning rod have a design life of approximately 15 to 18 years. The design life of the Nimbus lightning rod as claimed by the manufacturer is 15 years. However, the commercial guarantee is , 18 months from the date of supply.
The body of the Nimbus is made of AISI 316 grade stainless steel which is highly resistant of corrosion. Further, the electronics are encapsulated in an epoxy mould. Epoxy material being resistant to temperature and also a very bad conductor of heat, the outside temperature will not reflect on the electronic components housed outside. Hence, the Nimbus is fully capable of working in corrosive atmosphere and high temperature and high temperature areas upto 120 ËšC
The Nimbus is not recommended to be installed at top of the chimney or vent. Specially, in case of a vent which is emitting flammable or explosivegases, it is recommended to install the Nimbus on a near by structure which is taller than the vent to be protected and a safe distance away from the vent.
Since the tall Chimneys or vents are always structures with a narrow base, the conventional Franklyn Rods are ideally suited for protecting them. The conventional rods are also not affected by the temperature of the flue gases / other emissions of the chimney. However, it is to be noted that the conventional rods only protect these chimneys / vents and not the structures around them. This is because, as the height of mounting of the Franklyn rod increases, its angle of coverage reduces drastically.
The Nimbus lightning rod should ideally be mounted such that the tip of the Nimbus is 5 Mts above the highest and farthest plane on the structure to be protected. However, the Nimbus lightning rod should be at least 2 Mts above any other point on the structure to be protected (like Antenna, Cooling Systems of Air Conditioners, etc) to avoid flashovers.
The area covered by each Nimbus lightning rod varies depending on the level of protection and the height of mounting. Please refer to our catalogue to know the exact radius of protection offered by different models of the Nimbus lightning rod for different levels of protection and heights of mounting.
The Nimbus lightning rod does not require any special high voltage cable to be used as down conductor for its working. In fact, the governing standards for the ESE lightning rods, (The NFC-17-102), have specifically forbidden the use of such down conductors.
The Nimbus lightning rod is fully compatible with the GI strip down conductors and normal earth terminations. However, the resistance of the earth termination shall be less than 10 Ohms and the GI strip down conductor have at least 150 Sq.mm cross section area.
As per the standards , one down conductor shall be used where the building height is less than 28 Mts and 2 down conductors for building height more than 28 Mts. Also, of the width of the building is more than 2 times its height, then 2 down conductors are to be installed. However, from the point of view of safety it is recommended to have at least 2 down conductors for every installation irrespective of the height of the structure.
If a copper down conductor is used, the cross section shall be at least 50 Sq.mm. If GI down conductor is used, the cross section should be at least 150 Sq.mm.
It is advisable to use a flat down conductor instead of a circular down conductor. Since the lightning current is of a high frequency and consequently exhibits skin effect, a flat down conductor offers more surface area for the current to flow as compared to a circular down conductor.