gate valves / gear box operator

Hi everyone,

We have to install 16” and 20” lines for fire water service (fight fighting system). The owner counts at Exxon Movil standards (Global Practices).

I need to determine wether 16” and 20” OS&Y gate valves should have manual gear operator. GP-03-12-01 states “... Gate and globe valves shown in Table 5 shall be supplied with gear operators only if they are operated more than four times a year or are designated as critical valves.

According to Table 5 of GP-03-12-01, gear operator shall be used for 16" and 20" 150# gate valves. Howevere, those valves are not going to opérate more than four times a year; but, What does it critical valves refer to?

Thanks in advance.