If it's a new terminal, chances are the alarm has been going off in error and the airport personnel are used to it.

In general, you are supposed to evacutate the building when an alarm goes off....

BUT - I remember when they replaced the alarm in my office building and it kept on going off for no reason. Eventually they told us to ignore it and if there were a real emergency, our floor fire marshall would use a megaphone to announce an evacuation.

I suspect this may be the same situation.