Fire-separation for a single furnace
Help!! I’d like to convert a single family dwelling (raised ranch with a walk-out basement) into a 2-family. Zoning is OK, but I must separate the units with a fire separation. Unfortunately they share a single hot-air furnace. Any ideas short of installing a second heating unit?
The house is located in upstate New York, so winters can get rather cold.
Replies
Codes will vary - in my area metal duct through the firewall is accepted.
But ask your local officials
With my mouth I will give great thanks to the Lord; I will praise Him in the midst of the throng. For He stands at the right hand of the needy, to save them from those who would condemn them to death.
- Psalms 109:30-31
The problem is that the single furnace supplies heat to both units. Some people have mentioned fire dampers, but my understanding is that that works best if there is a single penetration through the fire separation. In this case, there is a single trunk line running down the middle of the house, and there are take-offs for both units intermingled down the length of the house.
How are you going to do temperature control? I'd think at the very least you'd have to separate the duct work with a zone damper in each leg.
So convenient a thing it is to be a reasonable Creature, since it enables one to find or make a Reason for everything one has a mind to do. --Benjamin Franklin
I would think you'd install a fire door in the duct.
If it were me, i'd shy away from common duct between units. You'll introduce all kinds of smells to each unit. What it one tenant smokes or cooks some crazy food?
More than likely you'll need to add some duct work for proper zoning anyhow.
I don't know about the code there but where I am, two dwellings can't share a furnace. If one side has people with allergies and the other side smokes, doesn't clean, has pets, etc, the other side will suffer.