Can Steam Set Off a Smoke Detector?

How Do They Work?

• The cheapest and most widely available types of smoke detector on the market are ionization detectors. These units consist of two metal plates attached to a battery and a small amount of a safe radioactive element, which ionizes the oxygen and nitrogen atoms that exist between the two plates. This process of ionization separates the nitrogen and oxygen atoms into ions and electrons that are each drawn to one of the two metal plates.

During a Fire

• If smoke enters the chamber, the particles attach themselves to the oxygen and nitrogen ions and turn them back into atoms. This creates a change in the electric current passing between the two metal plates, which in turn sets off the alarm.

Steam

• Sometimes these smoke detectors can be "fooled" by steam in the air, particularly during cooking. The particles in the steam can sometimes behave similar to the smoke particles that are supposed to activate the detector, which is why you often get false alarms. If this happens a lot, you might need to move your smoke detector further away from the kitchen.