Residential Generator Clearances
- Thread starter mike9593
- Start date
- Status
- Location
- New Jersey
- Occupation
- Journeyman Electrician
Are you asking if the chimney hatch opening would be required to be outside of the recommended clearance zone for the generator?
Gregg Harris
Senior Member
- Location
- Virginia
- Occupation
- Electrical,HVAC, Technical Trainer
Correct it would not be a means for ventilation for the occupied space.
mgookin
Senior Member
- Location
- Fort Myers, FL
I think you're asking "Would an access hatch on a chimney need to be considered as an opening when locating a residential generator?"
Are you talking about mechanical code requirements for building openings within 10' of a source of bad air? As in sewer vents, exhaust, etc.?
And can you elaborate on "access hatch on a chimney?" Is that referring to an ash dump? Or is it a door for loading firewood from outside, or something else?
- Location
- Placerville, CA, USA
- Occupation
- Retired PV System Designer
FWIW, the ash dump, being below the fireplace floor level and not fully sealed at that point, would be a potential CO entry point. If you turn on an exhaust fan inside the house, you could end up sucking fumes in through that opening. Is that a realistic hazard? I do not know, but I think it would come within the code limitations.
If you seal the opening in the bottom of the fireplace the situation changes.
mgookin
Senior Member
- Location
- Fort Myers, FL
And if the generator has receptacles on it, I can see someone running an extension cord through the ash dump door, up through the firebox, and into the home. People do what they have to do under adverse conditions.
In our area the chimney ash dump door is considered an opening to the building. Manuf instructions simply says opening.
On occasion when there is no other alternative we have sealed off the door. this passes inspection.
It must be sealed at least semi perminante. if you need to get the door open you can with a little work. Never an issue How many times do you need to open that door. almost never.
Gregg Harris
Senior Member
- Location
- Virginia
- Occupation
- Electrical,HVAC, Technical Trainer
R1003.2.1 Ash dump cleanout.
Cleanout openings located within foundation walls below fireboxes, when provided, shall be equipped with ferrous metal or masonry doors and frames constructed to remain tightly closed except when in use. Cleanouts shall be accessible and located so that ash removal will not create a hazard to combustible materials.
Ash pit doors are designed with a fiberglass gasket that renders them airtight. and are at ground level.
The specific gravity of CO is less than air and when exhausted by a combustion engine will rise due to flue gas temperatures being higher than ambient temperature and the fact that it is lighter.
- Status