Question is open for the forum..the conclusion that I draw from material available on internet is that most types of check valves are suitable for use on both liquid and gas systems. Reference:
Design is the same as far as I know. I've never seen an nrv with different design depending on whether it has gas or liquid, they are both fluids so shouldn't really matter.
My motto: Learn something new every day
Also: There's usually a good reason why everyone does it that way