Testing propane alarm in more life like conditions?

Almot wrote:
Yeah, but how do you know that butane lighter created real-life dangerous level? It could've triggered the alarm way before that level was reached. Or - way later.

Here's what you do:fill a balloon that is easily inflated, with air. Add in enough propane so that the balloon contains just enough air and propane to be ignitable (maybe a little lean, eh). Release the contents of the balloon in front of the sensor.