Can E-Cigarettes Set off Smoke Detectors? The Definitive Answer

When South West Airlines Flight 3654 took off from Ft. Lauderdale, Florida, no-one expected any problems.
But one passenger was suffering from nicotine withdrawal.
So part way through the flight he sneaked off to the toilets to stealth vape.
But shortly after he, along with the rest of the passengers, had a massive shock when the plane’s fire alarms went off, forcing the pilot to make an emergency landing.

Can Vaping Set Off Regular Smoke Alarms?
Some people will tell you that vapour can’t set off smoke alarms – in fact, I was even told that by a fire expert when researching this article.

We wanted to find out if vapes can set off fire alarms, so we decided to blow vapour directly into a fire alarm. 
Now, that’s a bit extreme. In the example, Tom blew directly into a smoke alarm. Both Tom and I vape in the office all the time, and I’ve never set off an alarm until I blew straight into one, even when using the Aspire CF Sub Ohm battery and having a cloud chasing competition with our mixologist. (It’s a hard life working for an e-cigarette company )

According to Alan Morgan from St Davids Fire, even a bit of cigarette smoke shouldn’t set off modern fire alarms, which have been designed to avoid false alarms.

Nevertheless, if you do use your e-cig indoors, or even worse on an airplane (please don’t – the consequences can be serious, as Rory Sutherlend found out when he spent a night in jail in Qatar), there is a small chance that your e-cigarette could set off an alarm – especially if you blow large clouds!

(And in fact, if you’re a bit absent minded like me, it might be worth keeping your e-cig out of easy reach when on a plane!)
Which types of fire alarm are vulnerable to vapour?
There are different kinds of fire alarms, and some are more likely to be set off than others.
Ionisation: Sensitive to small particles of smoke. They utilise two electrically charged radioactive plates. When smoke particles enter the fire alarm they disrupt the electricity between the plates, setting off the alarm. This was the type used in our little experiment!
Optical alarms: Optical alarms work by beaming infrared light. When smoke particles enter the smoke alarm, the particles cause the infrared light to be scattered onto a light detector which triggers the alarm.
Heat alarms: Used in kitchens, these are unlikely to detect vapour as they are responsive to heat rather than to smoke.
When we spoke to South Wales Fire and Rescue Service, they told us that optical alarms are the type most likely to be set off by electronic cigarette vapour, although as our little experiment showed ionisation alarms can be set off too.
How likely is your electronic cigarette to set off a fire alarm?
Fortunately, reports of electronic cigarettes setting off fire alarms are rare. Smoke alarms are designed to detect smoke, and electronic cigarettes produce vapour. In addition, vapour dissipates a lot faster than smoke.
However, the use of PG and flavourings is thought to create larger particles than the average steam from a kettle. And according to Ohio University, fog machines, which contain propylene glycol too, can also set off fire alarms.
So, setting off the average fire alarm is unlikely – but still possible.
Is it safe to vape in a hotel room?
Hotels vary in vape policy – some expressly forbid vaping, while others do not have a vape policy. (If a hotel is pro-vaping, it might be a good idea to support it).
But hotels often have more sensitive vape alarms than your standard office or house alarm. And when Tom was vaping in a Premier Inn he noticed that the smoke alarm had started to flash red.
Meanwhile, one poor Reddit commenter set off his hotel alarm at 7am in the morning, woke up the whole hotel and was asked to pay a $200 fine.
So if you are going to vape in your hotel room, it’s a good idea to note where the alarm is, and use your e-cig a safe distance away from it – or, if you are blowing large clouds, by an open window.
It’s also worth using a discreet device that doesn’t put out a whole load of vapour, such as a pod system or a pen style device, rather than a sub-ohm vape.
Will your e-cig set off a smoke detector in a plane?
Fire alarms in planes are extremely sensitive. Most if not all airlines do not allow you to use standard e-cigs in planes (although some airlines do sell vapourless versions).
As we saw earlier, some people have spent a night in jail for using an e-cig on Qatar Airways. That was an extreme example, but you could easily have your e-cig confiscated, have to pay a hefty fine or even be added to a no-fly list. In the UK you are not allowed to vape on most trains or buses either (an exception is South Eastern Railways).
Have you ever set off a fire alarm with an e-cigarette, or do you know of someone who has?