Any bell or horn for use as a fire alarm - with the exception of the ones in your smoke alarms - are required by UL to be at least 105 decibels LOUD.
That said, I've had a few poorly operating bells .... the last one I am certain was 'saved' by the other guy just to annoy the sparky
The flow switch used on the sprinkler may have a 30 second delay built into it. That is, water must flow for 30 seconds before the bell will sound.
Whoever made your smoke alarms ought to have some means, some accessory perhaps, for tying the alarms into a central station panel. The panel, in turn, would have whatever is needed to activate the alarm bell.
Yet - as a recent experience of mine illustrated all too well - you really need to obtain, and READ, every code that's being used by the various authorities. Fire Alarm code, Sprinkler code(s), local codes, etc. One thing I have noticed is that there are many - including the inspectors!!!! - who have never seen the actual codes, let alone read them. Their 'seminar training,' as a result, led to all manner of false assumptions on their parts.