ERICO® has conducted two unprecedented, long-term field-validation studies of the Collection Volume Method of lightning protection with the ERITECH® SYSTEM 3000 lightning-protection system. The Collection Volume Method (CVM) defines the lightning "capture volume" of potential strike points on a structure.
The first study, conducted from 1988 through 1996 in Hong Kong, demonstrated that it is possible to dimension the interception efficiency or performance of a lightning protection system using real field data. This method circumvents the problems associated with laboratory testing, where scale-size issues are difficult to resolve and faithful replication of the electric field wavefronts observed in nature can also be troublesome.
The number of strikes to the protection system of the structures in this study were obtained from "lightning event counters" (LEC) placed around the lightning current downconductor cable. All of the LEC's were tested and calibrated using an 8/20 μs current impulse. Overall, estimates of the strike "yield" demonstrate that the interception rate predicted by the CVM is in excellent agreement with the observed capture frequency. This means that the lightning-interception rate is at least as high as the claimed protection levels, which lie in the 85 - 98% range.
The second study, conducted from 1990 through 2000 in Malaysia, quantified interception efficiency. The study consisted of a statistically valid sample of buildings mainly in the Klang Valley region of Kuala Lumpur. The 47 sites had between 1 and 5 buildings per site with a mean structure height of 58m (190 ft). The mean actual protection level was 78%, meaning that up to 22% of low-intensity flashes under 10 kA could be allowed to bypass the lightning protection system (LPS). Mitigating factors such as budget constraints and subsequent changes to the structures (e.g. the addition of antennas and extensions) impacted the initial design and prevented the protection level from being higher. At the end of the study, the actual interception efficiency was 86%, ten percent better than predicted.
The patented ERITECH SYSTEM 3000 is a technically advanced lightning protection system that offers reliable lightning capture. The system incorporates the ERITECH® DYNASPHERE MKIV air terminal that provides a preferred dissipation point for lightning discharges. The air terminal places ERICO at the forefront of advanced lightning protection technology worldwide. It represents a number of improvements over existing technology including a mechanically stronger design, reduced visual impact and more versatile applicability across facilities. The unit is part of a complete lightning protection system that offers users a total solution for lightning capture, conduction and grounding. The system also includes ERITECH® ERICORE down-conductors, lightning event conductors, a purpose-designed low impedance grounding system and air terminal placement software.
For more information, visit www.erico.com or call 1-800-677-9089.
ERICO® is a leading designer, manufacturer and marketer of precision-engineered specialty metal products serving global niche product markets in a diverse range of electrical, commercial and industrial construction, utility and rail applications. The company is headquartered in Solon, Ohio, USA with a network of sales locations serving more than 25 countries and with manufacturing and distribution facilities worldwide. ERICO's well-known brand names include: CADDY® fixings and fasteners; CADWELD® welded electrical connections; CRITEC® surge protection devices; ERICO® rail bonds; ERIFLEX® low-voltage components; ERITECH® lightning protection and grounding; and LENTON® mechanical rebar splices. Visit ERICO online at www.erico.com.