Reliability?

I am responsible for about 170 flats, they all have domotics to control different things in them. These installations are rather old.
The flats are inhabited by elder people, so some ports are used for nursing calls.
Because of price matters, I seriously think to change the existing hardware with Arduino-powered hardware.
But... Is Arduino reliable enough to use it for non-amateur purposes? Could it been used for years?

Or (which I hope not) is it just a nice gadget?
Please, those who have experience with it, help me decide...

Thanks in advance,

Marc

Have a look here :
Waranties
In particular 1.5 point

Using the Arduino for a life-critical role like a nurse call is totally inappropriate; you absolutely should not be using Arduino's in situations where a failure could cause damage, injury, or loss of life. If it failed, you could expect to be sued for everything you have and possibly sent to prison for criminal negligence - not to mention living with the knowledge that you killed someone through negligence for the rest of your life. Using hobby electronics for that kind of thing is ridiculously reckless.

For things where a failure is only a nuisance, arduino is reliable enough, if you code and assemble everything right.

Thank you for your replies. Very clear!