You may be wondering, how does lightning finds its way into a fire alarm system? When storms hit, often lightning strikes and with that comes a chance your fire alarm system may be struck by a direct, or indirect, hit.
Lightning creates an electromagnetic pulse energy which can cause damage to devices by generating over-voltage and power surges. These surges are short-lived, momentary bursts of energy that drive tremendous amounts of current into an electrical circuit for a few millionths, or a few thousandths, of a second.
When lightning strikes a fire alarm system it can cause damage to installed and connected components or the entire system.
Anything wired to the fire alarm system is subject to damage when lightning strikes. Fire systems can remain online after a strike but may show alarms or faults when there is no need for it.
Installing surge protectors in case of lightning
Installing surge protectors is the best way to protect a fire alarm system. There are two ways you can install surge protectors;
1. Install a surge protector on the power supply circuit of a fire alarm panel. The main circuit is the power circuit coming into the fire alarm panel from the switchboard.
2. Install surge protectors on the circuits that go out from the panel to the devices, like smoke detectors, signalling devices, and brigade calling equipment.
Risks and costs
When a fire system is effected by lightning the major risk is that the system will be offline for an uncertain amount of time.
Getting it fixed then depends on whether the damaged parts are promptly available, from the fire system supplier, so they can be replaced. If lightning effects a system on the weekend the system will most likely be offline until the following workday.
When lightning strikes a fire system it can be extremely costly. For example, if the fire alarm system is offline a safety measure, like a security guard, needs to be put in place and in worst cases the main CPU of the fire panel must be replaced.
Costs for repairing a fire alarm system, after a lightning strike, can be up to $10,000.
Statistics
It will be estimated there are 2-3 lightning strikes per square kilometre per year across Australia. At 7.692 million square kilometres, that would be somewhere between 15.4 and 23.1 million strikes per year.
If you think that’s high, consider that worldwide there are 100 lightning strikes per second, or 8.6 million per day. Australia’s few million strikes per year are a small fraction of the total lightning activity worldwide.
Images of surge protection:
Myths about Lightning
- Lightning never strikes the same place twice – FALSE
- People who have been struck by lightning should not be touched as they are electrified – FALSE
- Lightning only occurs when there are thunderstorms – FALSE
- Lightning always strikes the tallest object – FALSE
Remember, the chances of a faulty fire alarm, during a thunderstorm, is less likely if you properly maintain your alarm system. If you would like advice about protecting or maintaining your fire alarm system, don’t hesitate to give our team at Form1 Fire a call.
