A Total Systems Approach to Electrical Grounding May Save Millions of Dollars
Lightning storms occur on average 130 days a year in Florida’s “Lightning Alley,” making this area one of the most dangerous in the United States with respect to weather- related incidents.
It is not true that lightning never strikes the same place twice. Communications towers in this area are prone to being hit during any major thunderstorm. If not properly equipped, this regular lightning activity can cause millions of dollars in damage.
Orange County, Florida, is in the heart of the Alley, and it sees more than its fair share of damaged buildings, disrupted power lines, fires and, unfortunately, injuries caused by lightning strikes.
As the former supervisor of radio services at Orange County’s Public Safety Communications Division, Tom Sorely was responsible for keeping its 820,000 residents safe. It was his job to make sure that the communications lines remained open 24-7, however this task wasn’t always easy when overseeing 9 tower sites and 10 emergency response centers in the county.
“We’re in the most lightning-prone area of the country,” Sorely said. “Our antennas are at the top of 300-ft lightning rods!"
Sorley explained that one or two strikes per month on a large tower were routine between the months of May and October.
“They don’t all do damage. But we have lost our entire network at times and every public service agency is in jeopardy when that happens,” he said. “Lightning strikes can be costly!"
Over the last 10 anos, lighting strikes have caused nearly $2 million in damages to transmitters and other lost equipment.
David Brender, National Program Manager for the Copper Development Association’s Electrical Program, urges all building owners and facility managers to check their electrical grounding systems and to take a “total systems approach” when evaluating lightning protection.
“A well-placed lightning strike can seriously compromise any facility, leaving lost equipment and damaged electronics in its wake,” said Brender. “Lightning protection systems that benefit from the inherent conductive properties of copper may give buildings the best chance to avoid this unpredictable damage.”
In essence, proteção contra raios é o processo de criação de caminhos elétricos de menor resistência, a fim de direcionar os raios para o solo e para longe de onde possam causar danos.
Sorley explicou que os sistemas de aterramento das instalações estavam em conformidade com os códigos elétricos quando foram construídos, mas nem todos foram projetados pelo mesmo empreiteiro, o que eventualmente levou a problemas.
“Nenhum indivíduo ou empreiteiro entendeu o aterramento como um sistema total,”disse Sorley. “O aterramento e sua manutenção eram algo que todos consideravam garantido. O que temos agora é uma abordagem sistêmica total para proteção contra raios.”
A “abordagem de sistemas totais” começa com os materiais. Radiais de cobre, pratos, eletrodos, condutores e fiação são essenciais para o sucesso de um sistema de proteção contra raios. Resistência à corrosão, confiabilidade e condutividade superior tornam o cobre o metal ideal para um sistema de aterramento robusto.
A CDA recomenda que os gerentes de edifícios e instalações tomem as medidas necessárias para proteger suas propriedades contra danos causados por raios. Uma “abordagem de sistemas totais” com aterramento de cobre fornecerá o melhor suporte para aquelas áreas onde um raio cai duas vezes.