A recently installed outdoor backup power generator has 3/4 inch pipe
exposed to the local climate, which is snow and ice for about 6 months of
the year, and rain for another 2 months or so. The fittings have already
begun to show rusting even though they have only been installed for a few
weeks.

I am asking whether a protective coating of paint or something else makes
sense, and if so, what to use. I am also concerned that some of the
"obvious" choices like Rustoleum paint will seep into the fittings and
compromise the pipe dope / joint sealing. It seems that Rustoleum's primary
ingredient is "petroleum distillates" and this may act as a solvent on pipe
dope.

I appreciate any suggestions as to how to proceed.

Many thanks,

Smarty