By Kim Loehr
December 1, 2015 — Lightning packs a powerful punch. A single bolt carries up to 100 million volts of electricity and has the power to rip through roofs, explode walls of brick and concrete, wreak havoc with circuitry and ignite deadly fires. It is no wonder experts with the U.S. National Weather Service have dubbed lightning as “the most dangerous and frequently encountered weather hazard experienced by most people each year.”
While lightning poses significant safety and economic concerns, there is good news for design/construction professionals and property owners. Unlike threats posed by tornadoes, hurricanes, or floods, lightning is a force of nature for which affordable and reliable protection is available. A lightning protection system that meets all applicable safety standards from the onset will ensure system reliability for the future.
As long as lightning’s electricity is confined to a conductive path (i.e. the quickest route to the ground), it will not cause damage, explains Bud VanSickle, executive director for the Lightning Protection Institute (LPI). “Only when electricity encounters resistance does it cause destruction,” he says. (LPI is a leading resource for lightning protection and lightning safety information. Visit www.lightning.org for a list of certified contractors in Canada and the United States Information about follow-up, third-party inspection services is available at www.lpi-ip.com.)
Resistance is the concept behind arc-welding. When electrical current runs through an arc-welder, the resistance it encounters while arcing through air generates the heat necessary to melt steel. Unlike the arc welder, the highly conductive copper and aluminum materials used in a lightning protection system provide a low resistance path to safely ground lightning’s dangerous electricity without allowing it to ‘jump’ or ‘sideflash.’ When the lightning protection network is in place, the lightning strike is intercepted and directed to ground without impact to the structure, occupants, or contents.
Lightning protection standards
Lightning systems must include the following elements:
• strike termination network (i.e. air terminals or lightning rods);
• down-conductor network;
• grounding electrode network;
• equipotential bonding network; and
• surge protection devices (for all incoming power, data, and communication lines).
Failure to make proper provisions for special grounding techniques of these five elements can result in inadequate levels of protection.
Construction managers, engineers, and affected consumers should familiarize themselves with the fundamentals of lightning protection specification, installation, and inspection. While reference to the safety standards is crucial for proper installation and application, recent changes in Canadian regulation regarding inspections for lightning protection may be a source of confusion and misinformation about the trade and industry best practices.
In January 2011, the Government of Ontario repealed its Regulation 712, also known as the Lightning Rods Act. The repeal ceased the administration of lightning rod inspections by the Office of the Fire Marshal (OFM). The act was first introduced in 1922 to address concerns about inadequate lightning protection system installations in Ontario. While the regulation did not require system installations, it provided a licensing system for distributors and installers and authorized the OFM to inspect systems.
Although the inspections will no longer be provided by the fire marshal, OFM continues to offer guidance for lightning protection system installations and is still recommending compliance with established safety standards—the Canadian Standards Association (CSA), National Fire Protection Association (NFPA) and Underwriters Laboratory (UL).
“There is nothing currently in the building code about lightning protection installation or inspections for structures in Alberta,” said Carol Henke, public information officer at the Calgary Fire Department.
Henke explained different provinces in Canada have different codes that can be augmented with bylaws to respond to the needs of a particular region. She said fire safety officials support lightning protection efforts in Canada regardless of building code requirements or omissions.
“Our department is committed to serving the community through excellence in prevention, education, and protection and by delivering fire safety outreach to Calgarians,” said Henke. “Naturally, we are very supportive of safety measures that go above and beyond to protect citizens.”
The Lightning Protection Institute (LPI) is also increasing efforts to improve the best practices for lightning protection in Canada.
“LPI membership includes installation companies in Canada committed to bringing this high level of service to their markets, along with U.S. member contractors who work in the provinces,” said VanSickle. “We believe the market for lightning protection is going through a transitional period and LPI plans to be an active partner in developing professional quality solutions that eliminate concerns for all users of lightning protection.”
Excerpted from Construction Canada. To read the full article visit http://www.kenilworth.com/publications/cc/de/201512/files/100.html