How to handle 'not a number' in postgresql

I am new to this group so forgive me if this is the wrong area to post
in.

I have some field data which comes off of a data logger. In some cases
the data is out of bounds of logger or instrumentation. In which case
it is reported as 'NaN' for 'not a number.'

Is there such a value in postgresql? If not I will have to hack it in
with a boolean and would rather not do so.

TIA