DAS is Not an ESE

There is a common misconception in the marketplace that the Dissipation Array ™ System (DAS™), designed and patented by Lightning Eliminators & Consultants, Inc. (LEC), is the same as an Early Streamer Emission (ESE) air terminal.  DAS is not an ESE and the science behind them is completely different. The only similarity between the two is that both are used for lightning protection. While the DAS prevents the formation of a lightning strike within the protected area, an ESE collects the strike, much like a conventional lightning rod (a.k.a. Franklin Rod), inviting it into your environment much like a fox in a hen house. Not only does this invite potential primary damage, like an explosion or fire, it can and often will produce a ‘meantime between failure’ effect which impacts the life and functionality of equipment and electronics which is often not detected immediately, but definitely has an impact and can be extremely costly.

Lightning Protection

To better understand the two technologies’ approach to lightning, it makes sense to briefly review how lightning forms: Lightning is nature’s attempt to equalize the voltage between storm clouds and the earth. During a storm, upward “streamers” of positively charged ions and “stepped leaders” of negative ions coming down from the clouds attach to each other to create a strike. The naturally occurring electric fields and stepped leaders that thunderstorms create give streamers the energy to rise upward from the ground (and ground based objects like buildings, trees, towers etc.) in search of stepped leaders.

According to the National Institute of Standards and Technology (NIST) ESEs are lightning attractors, much like a conventional lightning rod. However, they are equipped in some fashion to trigger the early initiation of upward streamers, increasing the efficiency of lightning attraction as a way to extend the effective range of protection over and above that of conventional lightning rods. For over 200 years, lightning rods have been used as a means to collect and control lightning strikes. But is it wise to allow thousands of electronic volts to flow around facilities and sensitive electronic equipment when another system that discourages strikes is available?

DAS is a Charge Transfer System (CTS) that is based on physics and state-of- the art engineering principles specifically designed to stop a lightning strike from terminating where it is not wanted in a designated “area of protection.” It is the only type of system where the lightning impulse is not encouraged, but discouraged. Discouraging strikes ends up being a significant benefit to the companies looking to effectively manage risk. In fact, it is a preferred route to lightning protection in a number of industries where lightning strikes pose a threat, including the oil and gas, information technology, nuclear energy, power generation, chemical manufacturing sectors and more.

DAS completely isolates protected facilities from a direct lightning strike by bleeding off the induced charge of the protected area during the course of a thunderstorm, reducing it to a much lower level in relationship to the surrounding environment. In other words, the DAS and charge transfer method reduces the naturally occurring electric field in a protected area, therefore upward streamers do not get enough energy from a storm to connect with downward leaders.

In a study completed by LEC, at the customer site of Tri-State Generation and Transmission Assoc. who suffered a debilitating major strike before they employed DAS, found that electric fields inside the protected area during thunderstorms was on average 55% weaker than the electric field in the surrounding area. Tri-State, which installed a DAS in the early 1990s, has had its system checked and re-certified by LEC on schedule every year. The customer has never had another direct lightning strike in its protected area since installing the system. Similar studies were done at additional sites, like Browns Ferry Nuclear Facility who has used DAS since 1998 and continues to do so with very similar and positive results.

Once the DAS system is installed, it requires maintenance and recertification which is recommended and should be completed annually in order to protect the viability of the unit and ensure the protected area remains intact. Yearly recertification is also needed to maintain the terms of the “No-Strike” warranty issued with every DAS. If annual recertification by Lightning Eliminators is not conducted, the No-Strike Warranty is no longer in place and there is no certainty that your system will function properly when needed. There are several LEC customers that after an event will call and ask for an inspection, and others who self-inspect and have ascertained that an incident has occurred and the system does in fact need repair. Then there are also those customers who do not examine their solution and are shocked when a lightning strike actually hits them. Lightning Eliminators not only offers recertification but a host of additional services to assist in maintaining your systems, but it is up to the end user ensure that maintenance is scheduled and upkeep is managed.

The video below shows Lee Howard, an Engineering Services Manager of Lightning Eliminators and Consultants discussing the benefits of discouraging and preventing lightning strikes from damaging buildings and personnel rather than collecting it and inviting powerful energy into grounding systems, thus creating vast damage to structure and process systems.

To date, LEC has installed over 3000 solutions in over 69 countries and throughout the United States, providing lightning protection to companies in the petrochemical, oil and gas, biochemical, information technology, nuclear energy, utilities and manufacturing industries.

Roy B. Carpenter, Jr., a former chief engineer for NASA’s Apollo Moon Landing Missions and the Space Shuttle design engineering teams, founded LEC in 1971 to study and apply engineering principles to lightning protection. His unique charge transfer process — the patented technology used in the LEC DAS solution – reduces the rapid transfer of electrons that occurs with lightning into a slow drip by pushing storm-induced electric charge up into the atmosphere, above a protected site. With more than 40 years of lightning protection success, LEC is able to issue a full no-strike warranty to each of its DAS customers, as long as proper maintenance is observed.