Not at all, thats where most backup generators are located. they have worked evry well for years in that location.
Its not as if you are suggesting having large volumes of fuel to power them, on an upper floor is it ?
If you haven't encountered the situation before that proves little. How much experience do you have in assessing risk of design construction criteria ? Zero at a guess.
Anyone can be a smart*rse after the event (I am particularly good at it
- ask my wife)