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What is lightning Protection?<br>The convential form of lightning protection, lightning arrestors or Franklin Rods, are just metal rods mounted on the top of a structure and then grounded using a series of conductors. <br>
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Do Early Streamer Emission (ESE) Lightning Protection Systems Work?
What is lightning Protection? The convential form of lightning protection, lightning arrestors or Franklin Rods, are just metal rods mounted on the top of a structure and then grounded using a series of conductors. This system is intended to protect the structure by making lightning preferentially strike the lightning rod, instead of the structure, allowing the dangerous electrical surge to be grounded by passing through the conductors and then the ground rod. Based on the class of protection for the structure, decided using a lightning risk assessment system, the lightning arrestor has a defined zone of protection. If any part of the structure goes is outside this zone of protection, more lightning protection, conductors and grounding will be required.
How is Early Streamer Emission (ESE) different? According to the ABB website, “(d)uringa storm, when propagation field conditions are favorable, an OPR ESE air terminal will generate an upward leader” which “propagates towards the downward leader from the cloud at an average speed of 1 m/µs”. According to the same website, this propagation “delivers a beneficial triggering time compared to a single rod air terminal exposed to the same conditions”. Thus, in essence, ESE is advertised as a technologically superior lightning arrestor to the convential form of lightning protection because the upward leader is advertised as increasing the zone of protection thus allowing a structure to utilize fewer lightning arrestors.
Are these Claims True? Currently, some of the largest manufacturers for Early Streamer Emission products are from Spain and France and thus, the only testing standards for ESE are from these countries (N FC 17-102 is the French Standard). TheInternational Electro technical Commission (IEC) prepares and publishes International Standards for all electrical, electronic and related technologies and is the leading international organization in its field. IEC 62305 - “Protection against lightning", published by this body, is the international standard for lightning protection from which most national standards are derived. This standard clearly states in the first line of its introduction that, "There are no devices or methods capable of modifying the natural weather phenomena to the extent that they can prevent lightning discharges". You can find a preview of that standard here .
This standard also states that the zone of protection determined for an air termination system shall be defined only by the physical size of the system and that there is a lack of proof if this zone can be enhanced. The most basic claim of ESE manufacturers is that their product helps enhance the zone of protection but the international standard for lightning protection states that there is a lack of proof on whether or not that is true. The most common standard in the United States for lightning protection is UL 467 which also does not recognize ESE.
As IEC’s name implies, these international standards are drawn up through a consortium of industry professionals who look at all the available research. Despite ESE having been on the market for several decades, none of these major standards have recognized it. Lightning protection and earthing/grounding are important elements to keep in mind for any structure. Please carefully review the literature on the subject and make an informed decision that helps protect the people and the equipment inside your buildings.
Axis offers a full range of products for lightning protection and grounding/earthing systems that have been tested as per international standards. Please visit our website to learn more about them. To learn more about the standards for lightning protection and system design, you can watch our video on the subject or read our blogs. If you have any further questions or requirements, please feel free to ask us here or email us at marketing@axis-india.com.
