fuel vent

hi everybody
i have a quetion about the location of fuel vent and air vent on fuel tank.
do we have any standard for the distance of these?
do we have any restriction for these?
at last ; do we have any standard for design of the fuel tank which describe all limitation about it?

 

Vents for tanks in boats, are perfectly regulated. See the rules that apply to your boat.

 

my boat is under ABS std
would you direct me,where i should see for it?

 

have a look : http://ww2.eagle.org/en/rules-and-resources/rules-and-guides.html