Max. # Gas Smoke Pipes

Can anyone point me in the right direction re: maximum number of gas smoke pipes allowed to feed into one chimney flue? I had a house recently with three gas appliances (boiler, furnace, hot water heater) all venting into one chimney. Wondering about restrictions and if they would be based upon the number of appliances, flue size, BTU’s, or some combination of the above? Thanks.

Thomas, it depends on different variables like size of piping into chimney, etc.

Google this PDF: " Chimney & Venting Sizing Handbook - Selkirk "


Thanks Larry!

I googled gas smoke pipe and this is what I found

In Colorado and California there is no limit. In Texas, they are not permitted.


That’s some funny stuff :joy:
Is that why you’re moving to Colorado lol