Originally Posted by
Jeff Euriech
Keep in mind that Table G2428.3(1) is for multiple vents (two or more) and would not apply for a single water heater.
Keep in mind that I am presuming you are addressing all related to those tables, like you should, and if you went to Appendix B (IFGS) you will have see the drawings showing all ... ALL ... *ALL* ... appliances with that same vertical riser before and horizontal run.
No, that vertical rise is not specifically stated as to its height, however, if you view, for example, Figures B-17 and B-18 you will notice that one rise is "2 ft" and the other rise is to the connector of the first one is "3 ft", and, looking at the drawings you will see that the rise of the second one to its horizontal offset is '1 ft' (3 ft - 2 ft = 1 ft), then, reviewing back through the other figures, you will notice that same rise, or higher, before any horizontal run.