Furnace exhaust code in Chicago?
fredz9
| Posted in Energy, Heating & Insulation on
I’ve been looking into getting a new gas furnace, but I’ve gotten conflicting information on what the building code in Chicago requires re the exhaust. One person who gave me an estimate said that the exhaust must be at least 15 feet from any other building. That would require running the running the exhaust ~30′ so it can exit at the back of the house. But someone else said that the only requirement is that the exhaust be 3′ from any door or window. In that case, we could run the exhaust through a wall that’s right next to the furnace. Anyone know about this? Or where I can find out? (The Chicago building code is online but I’m not sure I can decypher it.)
thanks
Replies
Ah Chicago code
While I do live in Chicago, I am not an authority on this aspect of the code, but that first requirement sounds rather absurd. I doubt that the top of my brick chimney is 15 feet from my neighbor's roof. I don't think the two houses are 5 feet apart.
Where in Chicago are you located? Pray tell, what vendor told you this? I am curious. While I have my own issues with the company, I bet Heatmasters (northside) is big enough to know the answer.
Good luck.
I don't know about chicago requirements, but the 3' "rule" is inaccurate - each manufacturer specs cleaces and you have to follow them
Yeah (assuming this is a condensing furnace), generally it's in the manufacturer's specs, but 3 feet is the norm for a standard install. The install instructions will have 2-3 pages of diagrams showing all the different scenarios and specs.
Not to say that Chicago doesn't have different rules. In fact, it's probably technically impossible to install a furnace in Chicago, if you follow all the rules.
But whoever quoted the 15 foot rule may have not been speaking of condensing furnaces. There's generally a rule that the top of a chimney must be something like 10-20 feet horizontally from any other structure, including the roof of the current house.
>>There's generally a rule
>>There's generally a rule that the top of a chimney must be something like 10-20 feet horizontally from any other structure, including the roof of the current house.
I haven't seen that one -
Off the top of my head, 2' above any surface within 8' - although some codes tie it to roof pitch
The furnace I currently have exhausts through a chimney, but the replacements I've been looking into don't. They are high efficiency gas furnaces (AFUE=95%, e.g. Lenox G61) and as I understand it they all exhaust through the wall. At least that's what everyone's recommend. The person who cited the 15 foot rule wants to run exhaust pipes across the basement and through a wall to the backyard. I assume that the furnances I've been looking at are condensing, since they have efficiencies > 90%.
Yep, anything above 87% (IIRC) is condensing.
I'd be suspicious of this guy.
Another thing: Even the rule about distance from a window is considered irrelevant around here (by installers AND some reasonably picky inspectors) since most people around here have the common sense to close the windows when the furnace is running.
The furnace I currently have exhausts through a chimney, but the replacements I've been looking into don't. They are high efficiency gas furnaces (AFUE=95%, e.g. Lenox G61) and as I understand it they all exhaust through the wall. At least that's what everyone's recommend. The person who cited the 15 foot rule wants to run exhaust pipes across the basement and through a wall to the backyard. I assume that the furnances I've been looking at are condensing, since they have efficiencies > 90%.
Can't the chimney be re-used?
I was under the impression that the proper exhaust piping is inserted into the existing chimney cavity, which is going to be a far shorter, straighter route than running the exhaust horizontally out to the back of the building. I am not a professional, but it sure sounds hokey to me.
I do seem to recall seeing such chimney inserts on TOH some time ago.
>>I was under the impression
>>I was under the impression that the proper exhaust piping is inserted into the existing chimney cavity
Not if the water heater is still using the chimney....
Every brand of condensing furnace I know of allows vertical termination of the vent, which, in your case, would sidestep all the complex requirements for horizontal venting that Chicago has overlaid on the nationally-recognized codes.
The Code requirements for venting of condensing furnaces simply tell you to use a listed appliance and then follow the manufacturer's installation requirements.
The Chicago Municipal Code for Vent Terminations
states:
"
18-28-804.3.3 Termination.
The termination of chimneys or vents equipped with power exhausters shall be located a minimum of 10 feet (3048 mm) from the lot line or from adjacent buildings. The exhaust shall be directed away from the building.
18-28-804.3.4 Horizontal terminations.
Horizontal terminations shall comply with the following requirements:
1. Where located adjacent to walkways, the termination of mechanical draft systems shall be not less than 7 feet (2134 mm) above the level of the walkway.
2. Vents shall terminate at least 3 feet (914 mm) above any forced air inlet located within 10 feet (3048 mm).
3. The vent system shall terminate at least 4 feet (1219 mm) below, 4 feet (1219 mm) horizontally from or 1 foot (305 mm) above any door, window or gravity air inlet into the building.
4. The vent termination point shall not be located closer than 3 feet (914 mm) to an interior corner formed by two walls perpendicular to each other.
5. Vent termination shall not be mounted directly above or within 3 feet (914 mm) horizontally from an oil tank vent or gas meter.
6. The bottom of the vent termination shall be located at least 12 inches (305 mm) above finished grade.
18-28-804.3.5 Vertical terminations.
Vertical terminations shall comply with the following requirements:
1. Where located adjacent to walkways, the termination of mechanical draft systems shall be not less than 7 feet (2134 mm) above the level of the walkway.
2. Vents shall terminate at least 3 feet (914 mm) above any forced air inlet located within 10 feet (3048 mm).
3. Where the vent termination is located below an adjacent roof structure, the termination point shall be located at least 3 feet (914 mm) from such structure.
4. The vent shall terminate at least 4 feet (1219 mm) below, 4 feet (1219 mm) horizontally from, or 1 foot (305 mm) above any door, window or gravity air inlet for the building.
5. A vent cap shall be installed to prevent rain from entering the vent system.
6. The vent termination shall be located at least 3 feet (914 mm) horizontally from any portion of the roof structure."
Looks like the hardest rule is the first one -- the Pulse rule.
Update
What did you end up doing. I'm in that same situation now