How long does a canned air horn last?

Question

Not the horn in a car, one in a can that are mainly used for races. I'm planning a senior prank, and I need to know how long they last if I were to tape the button down so they would continually make sound.

Answer 1

long enough to make someone punch u in the face hahahlol

Answer 2

oh you must share with me the details of your prank, i want to hear! sounds good.

anyways, on most bottles they will say something a long the lines of  up to ___ uses. i'll be back in a minute after i search.

EDIT: sorry cannot find anything... :/

but i asume a few hours if your lucky.

so tell me about your prank?