One more point about BASIC codes regarding a 3″ opening which is just a point if information.
A Fresh Air Inlet ( F.A.I ) is by proper design 1/2 the size of the building house drain or main trap BUT no case less then 3″
this F.A.I shall be located at least 6″ above grade and have a metal plate or return bend installed to prevent vandalism.
The size of the holes for this plate shall afford full flow.
In other words if the F.A.I is 3″ you would need 36 1/2″ holes to give you the same area Or if you used 1/8th inch holes you would have to drill 576 to give you the same area if you used 3/8 holes you would only need 64
[Edited by John Aldrich on 29 April 2001]