Venting of new construction
Okay, let me see if I finally understand these two rules. These two sections of the code are independent of each other?
1) Drainage piping shall be vented by means of one or more vent pipes, the aggregate cross-section area of which shall not be less than that of the largest required building sewer.
Therefore, if the main (largest) required waste line is 4", I could install two 4" vents through the roof which would equal double the cross-section area of the largest waste line. Since the code requires the aggregate cross-section area to NOT BE LESS than that of the largest required building sewer, this setup would meet the qualifications of this rule?
2) The diameter of a vent stack cannot exceed the diameter of the waste line to which it connects.
Again, since each of the two 4" roof penetration vents are not larger than that of the largest 4" building sewer, this setup would meet the qualifications of this rule?
Therefore, it is entirely within code to exit the roof with two 4" vents even though the maximum sewer line is only 4"?