You work hard to build and maintain your business. That’s why it’s important to ensure you’re protected rom all potential losses – especially when they are beyond your control. A lightning strike can result in damage ranging rom power surges to fre or even death. Understanding the risks lightning poses and ollowing the proactive steps provided in this guide can help you improve saety measures, reduce costly repairs and protect your property. The facts of lightning Lightning is an electric current, existing within a cloud where small bits oice are bumping into each other as they swirl around in the air. All these little collisions create electrical charges within the cloud, with a positive charge at the top othe cloud and a negative charge closest to the earth. Since opposites attract, the negative charge within the cloud causes a positive charge to build up on the ground below. The ground's electrical charge concentra tes around objects that point up, such as buildings, chi mneys, trees, and even people. T he charge streaming up rom these points eventually connects with the charge reaching down rom the cloud, resulting in a lightning strike. The intense energy concentrated in the lightning bolt causes the surroundin g air to ionize creating the boom we call thunder. It’s this concentrated energy which can destroy anything that gets in its way. The ollowing are common types olightning which may cause damage: Direct Strike A direct strike happens when lightning attaches to an object directly. The impact generates hundreds othousands ovolts and amps causing severe damage such as destroying brickwork, rying wires or starting fres. Side Flash As a lightning bolt travels along an object (conductor ), the high energy ionizes the surrounding air . Ianother object (metal, tree or masonry material ) is close enough when this happens, the lightning may jump the gap rom its conductor to the other object beore reaching the ground. Induced Voltage (Nearby Strike) A nearby strike can be very destructive, as a massive “electromagnetic pulse” (EMP) is generated when the lightning energy passes to the ground. EMP’s are particularly damaging to electronic equipment and operations. An induced lightning surge on overhead electrical distribution wires can deliver as much as 100,000 volts. Lightning surges can also enter buildings via other metal conductors, water lines, telephone lines, unshielded computer network CAT cable, cable television cables, etc. Protect your property Consider hiring a proessional lightning protection installer * to help protect your propert y rom lightning damage. Note: Some provinces require installers to be licensed and the installation inspected by the Ofce othe Fire Marshall while in other provinces electricians may do installations to standard. Your installation checklist: PLightning Rods (Air Terminals ):• Install rods on the building structure , bonded together and tied to the ground. Your guide to… 1 of 3 Lightning Protection AvivaCanada.com/risks
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7/27/2019 Your Guide to Cl-lightning Protection-jun12-Final
You work hard to build and maintain your business.
That’s why it’s important to ensure you’re protected
rom all potential losses – especially when they are
beyond your control.
A lightning strike can result in damage ranging rom
power surges to fre or even death. Understanding
the risks lightning poses and ollowing the proactive
steps provided in this guide can help you improve
saety measures, reduce costly repairs and protect your
property.
The facts of lightning
Lightning is an electric current, existing within a cloudwhere small bits o ice are bumping into each otheras they swirl around in the air. All these little collisionscreate electrical charges within the cloud, with apositive charge at the top o the cloud and a negativecharge closest to the earth.
Since opposites attract, the negative charge within
the cloud causes a positive charge to build up onthe ground below. The ground's electrical chargeconcentrates around objects that point up, such asbuildings, chimneys, trees, and even people. Thecharge streaming up rom these points eventuallyconnects with the charge reaching down rom thecloud, resulting in a lightning strike. The intenseenergy concentrated in the lightning bolt causes thesurrounding air to ionize creating the boom we callthunder. It’s this concentrated energy which candestroy anything that gets in its way.
The ollowing are common types o lightning whichmay cause damage:
Direct StrikeA direct strike happens when lightning attaches toan object directly. The impact generates hundredso thousands o volts and amps causing severedamage such as destroying brickwork, rying wiresor starting fres.
Side FlashAs a lightning bolt travels along an object (conductor),
the high energy ionizes the surrounding air. I anotherobject (metal, tree or masonry material) is close enoughwhen this happens, the lightning may jump the gaprom its conductor to the other object beore reachingthe ground.
Induced Voltage (Nearby Strike) A nearby strike can be very destructive, as a massive
“electromagnetic pulse” (EMP) is generated when
the lightning energy passes to the ground. EMP’s are
particularly damaging to electronic equipment and
operations. An induced lightning surge on overhead
electrical distribution wires can deliver as much as
100,000 volts. Lightning surges can also enter buildingsvia other metal conductors, water lines, telephone
Consider hiring a proessional lightning protectioninstaller* to help protect your property rom lightningdamage.
Note: Some provinces require installers to be licensedand the installation inspected by the Ofce o theFire Marshall while in other provinces electricians
may do installations to standard.
Your installation checklist:
P Lightning Rods (Air Terminals): • Install rods on the building structure, bonded
together and tied to the ground.
Your guide to…
1 o
Lightning Protection
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7/27/2019 Your Guide to Cl-lightning Protection-jun12-Final
• Earth grounds should be made by driving“ground rods” (minimum o 3.5 metres in length
and 18 mm diameter) into the earth. These provide
a low resistance path to ground i multiple ground
rods are tied together to orm a ring around the
building. In some cases, specifc ground plates may
be used. On bedrock, a horizontal ground radial
system may be the best.
• Ensure all electrical and lightning grounding
systems are tied together to orm a single unifed
ground system. This will reduce the potential or
damage due to high dierential voltages which
could develop i the grounding systems are not
connected.
• Use copper cable or ribbon as a conductoror grounding systems as copper has the bestelectrical conductivity, corrosion resistance, andthermal/mechanical stability. Note: secure copperto keep it away rom thieves or you could beunprotected!
P Building Protection• In Ontario, PEI and NB, systems must be installed
by a licensed and insured proessional (which
will protect you i the system ails to perorm asdesigned). In other provinces, a qualifed electricianshould be hired as portions o lightning protectionall under the electrical code as well as the buildingcode.
• Wood frame buildings: a purpose built lightningprotection (araday cage) system may be needed.
• Masonry buildings: focus on bonding andgrounding, especially or buildings with towersor metal domes (e.g. heritage buildings,churches, mosques)
• Modern steel structures: the building’s structural
steel rame is usually part o the groundingsystem but you should review the design withyour architect to ensure there is proper bondingand low earth to ground conductivity.
P Radio – TV – Telephone Network Protection• Connect any cables entering your building
(TV, telephone) to a surge arrestor specifcallydesigned or that service. All service cablesshould enter the building in proximity to theelectrical service entrance and the arrestorsshould be solidly grounded and bonded togetherto the service ground.
• All internal wiring should be “shielded”(e.g. telephone or CAT cable should have anouter metal jacket which can be grounded)or placed inside a grounded metal conduit.
P Fire and Security Alarm Systems Protection• Protect alarm systems by ensuring the panel has
surge protection installed by design. As well, allpower leads should incorporate surge protectionand communication cabling. Cabling or sensorsshould be shielded and grounded.
Long term protection
These measures will help keep your property saerom lightning damage. However, you must perorman annual visual inspection o your system, and werecommend to have the system inspected and groundconductivity tested every 5 years at a minimum.
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7/27/2019 Your Guide to Cl-lightning Protection-jun12-Final
For urther inormation on this topic, please contact yourindependent insurance broker.
Visit www.avivacanada.com/risks or more Your guideto… inormation sheets on other loss control topics.
Readers should seek specifc advice when dealing withparticular situations. Aviva Canada Inc. accepts noresponsibility or action taken as a result o inormationcontained in this publication. The inormation inYour guide to... is correct at the date o going to press.Printed and published by Aviva Canada Inc.,Website: www.avivacanada.com