My understanding is that the motion sensors “usually” use low voltage. But that does not mean that they are intrigently safe. I have no idea about how much isopropyl alcohol (C3-H8-O) you have, nor do I know the controls such as ventilation system or additional fire hazards such as any Oxidisers in your workplace etc etc. When it goes BANG (and you state two facts “isopropyl alcohol” and “non-explosive proof”) then you may have some explaining to do afterwards.

So I say NO. Walk away from that gem, better to error on the side of caution than to error.

Have you had someone previously undertake a risk assessment in accordance with DSEAR at your workplace? If yes they may have a comment or two.

Crack on.