Multiple concentric vent kits


I have two concentric vent kits I need to poke through the roof. One is for my furnace and the other for my tankless water heater. I want to place them near each other for aesthetic reasons, but I cannot find anything in the building codes related to the dos and donts of this.

As I understand it any exterior exhausts should be a minimum of 3ft away from a window – that is no problem. But is there a minimum distance these concentric vents must be away from each other? My brain tells me it shouldn't matter as long as they are at the same elevation since they pull fresh air from down and exhaust up – but I worry there is something I am missing code-wise

To be clear – I want to set them about 2ft apart…I just want to make sure I am not in any violation with that choice as it would be extremely difficult to change later

Best Answer

You're fine

IFGC 503.8 is the governing Code passage here, and it sets no minimum spacing for direct-vent terminations from each other, just from features that could draw combustion gasses into room air (such as fresh air intakes and openable windows).