Safety Requirements on 120Vac Board

I've designed a board with a few relays that switch 120VAC. I have the normally open side of the relay connected to a current limiting resistor and opto-isolator. Do I need to worry about single fault failure for safety testing? If so, can I just put two resistors in series?

By safety testing, you mean official certification?

Doesnt the current limiting resistor interfere with function? If it doesnt, isnt it too low to be protective?

Yes I mean official certification. I'm not exactly sure what you mean by 'interfere with function'. For certification, will I need to worry about single fault failure?