Sintra Engineering | Resolve Matters

Western Canada's
Forensic Engineering Experts

Sintra Engineering
Insightful, informative and current information on the latest industry trends and news.

Blog

Talk to an expert at:

1-877-244-6251

‹ View All Recent Posts

RSS Feed



Damage from Severe Weather

July 26, 2018


Being struck by lightning is an unusual occurrence - so rare that people use it to gauge the likelihood of other rarities. You are more likely to be struck by lightning than win the lottery, but did you know that “lightning kills more Canadians than hail, wind, rain and tornadoes combined”? (Canadian Red Cross - http://www.redcross.ca/blog/2010/7/what-are-the-odds)

On average, there are around 2.3 million cloud to ground lightning flashes every year in Canada, most of which happen in July (https://www.canada.ca/en/environment-climate-change/services/lightning/statistics/maps.html). A recent storm near Camrose, AB, generated over 440 cloud to ground strikes in a 16 km radius over a 6 hour period. Environment Canada suggests that lightning is one of the most common sources of weather-related property damage, and this is likely because a bolt of lightning can carry upwards of 100 million volts of electricity and can have a peak current of over 100 000 amps! That much electricity in an area can cause damages to structures and property over 10 km away. And, most damage isn’t because of a direct strike, it tends to occur because of the proximity to a strike.

Lightning strikes can cause damage in all kinds of ways; you might see direct damage to a structure, such as burns or damage to the roof of a house. Sometimes, though, you might not realize the damage is the result of lightning activity in the area. An electrical discharge of that magnitude might cause perforations in gas lines or damage to electrical or plumbing systems, if they aren’t properly grounded. Power and telephone lines can conduct lightning and cause a safety risk, even a distance away from the actual strike. Perforations in lines such as those entering or exiting a home can cause a fire, which might not appear at first glance to be related to severe weather, especially if the building itself wasn’t directly hit. In one case, a strike ignited the cellulose insulation of a building, which smoldered for hours before igniting into flaming combustion. Other ignition sources need to be eliminated before concluding that lightning was the cause, and occasions such as this can make it particularly difficult.

How do you know for certain if something is related to a lightning strike? There are a number of things we look for when assessing damages that might be related to a strike. Weather data is available from a variety of sources, some of which can provide locations of strikes on specific dates/times. The type of damage is also an indicator but might not be obvious. If the structure was directly contacted, the roof or siding might be burned or damaged; however, there might be underlying issues that go well beyond the buildings’ envelope.

So, what are the first steps if you think lightning might be a factor in your loss? First, is the building safe to enter - did the strike or resulting events damage the structure? If there is a possibility, a structural engineer should be called in to take a look and assess if the building is sound. They can then provide recommendations for repairs, or shoring if required, to ensure that further investigation or remediation work can be completed safely. After that, if lightning is suspected, an electrical or mechanical engineer might look for evidence of scorching, melted wire or evidence of arcing on electrical components or other metal materials. The electrical and plumbing systems might need to be inspected for damages which may otherwise be missed or overlooked.

Sometimes, while the damage might be related to a lightning strike in the vicinity, there are factors which contributed to the loss. Was everything properly installed or grounded? If not, the damage might have been exacerbated, and, sometimes, the loss might not have occurred at all if the installation had been completed properly, or the manufacturer had built in the proper safety systems.

Written by Kristie Dejong


Comments

Share This Post

Post has no comments.


Post a Comment

*All fields required. Your comment will be submitted for approval before it is posted.


Blog Categories

Recent Months


Subscribe to Our Newsletter



Click here to Subscribe ›


Follow Us On Twitter