Parallel Water Heater Flues

There are two gas water heaters side by side in the attic. Can someone please point me to the code that tells how far apart these parallel flues should be?

Thanks in advance.


Ricky I don’t know where you are located but here it is minimum of 18".
If they are over 5 feet high than you should recommend bracing.

Excellent. Thank you very much. I didn’t think to give my location - well, this house is in Denton County, Texas. These two are about 22" apart near the roof then end up just over 18" at the top.

Oh, and thank you for the image!

Get it on your Profile so those in TEXAS area can help your more.

OK, thank you. I’m fairly new to using the forum. Will do that now.