Can truck exhaust outside set off a carbon monoxide/explosive gas detector inside?

Question

My alarm went off one morning. The fire department found nothing, but there was a truck idling in the lot next to my apartment. When the truck pulled away, the alarm stopped but the firemen told me that wouldn't have caused it. He did suggest that if I sprayed perfume, that might have caused it, but that sounded a little silly to me.

Answer 1

I'd definitely suggest it was the truck exhaust.

Although there is nothing explosive in exhaust, the carbon monoxide could well have triggered it.

Alarm systems are notoriously (at least within fire services) sensitive - and take very little to set off. I've been to alarm activations set off by bathroom steam, a kettle, damp air (I'm not joking - damp air can trigger them), even someone blowing cigarette smoke into an air conditioner.

I'd suggest it's most likely the trucks carbon monoxide set it off though - also given that many modern detectors are wired so as they don't just pick up smoke but often the other by-products of a fire (such as carbon monoxide).  

Answer 2

It was the truck.

Answer 3

WHAT KIND OF PERFUME DO YOU USE ??? Just kidding. Did you have a window open? An untuned truck could deliver a ton of CO. It wouldn't take much to set off the alarm. I say it was the the truck, probably a 20 yr old chev or GM. Ever get behind one of these ? They'll make your eyes water.  

Answer 4

The only way that this could have happened is if you had a window or door opened so that the flumes could enter the apartment or you have a very bad leak somewhere else that is letting this in.

I would call the apartment manager and have them check this out just in case because this is something that you don’t want to let go unchecked.

Answer 5

If the truck was idling near a fresh air intake, it definitely could have set off the alarm. I have seen it happen in institutional buildings (including hospitals). The fresh air intake is positioned near the loading docks without thought to the idling vehicles, the air intake picks up the exhaust gases and concentrates it inside the building. It only takes about 5 parts per million of carbon monoxide to air to set off most alarms.