Roger Mills wrote:

[1] All alarms have a Test button - but the silencing button is an extra one
which silences it for a few minutes. If the smoke - or whatever - is still
there after a few minutes, it starts sounding again

Mine is handy in that it can be used preemptively. So if I'm frying a
steak (which is guaranteed to set off the alarm outside the kitchen
door) I press the button before I start and get 15 minutes' grace to
make as much smoke as I like before it will go off.

Pete