Air vent sizing for sprinkler riser

[sv879]

Greetings

I would like to check with you is there any sizing calculation available for air vents (at top of sprinkler riser).

I have checked NFPA13 and couldn't find anything other than 15mm size mentioned for manual air vents.

Would it be possible to get your valuable advise?

Thank You.

 

[MGXFP]

There is no size requirements, a listed air vent is good for any size wet pipe system.