Yeah, if it is inaccessible to cars, it is not a garage.  It’s just a storage room with an overhead door.

You may want to sketch out a blueprint of the proposed installation, and actually label the room “storage and mechanical room” or something.  If you call it a garage, they certainly will.  And label the door “overhead door,” not “garage door.” If you make it clear that it is something other than a garage, it should make your life easier.

Joe

thats some real good vergage right there too.  with a boiler in my garage, with the size of the boiler, proper clearences etc, there will probably only be 6’ of usable space left.  can hardly be considered a garage then.

The verdict is in. According to the State Fire Marshalls office, you could build a mechanical room inside a garage & have it contain a wood fired boiler per the code. Access to the room would need to be from outside, not inside the garage.
If you have no where else to install a boiler or are unable to rig it into a basement
this is a pretty decent alternative in lieu of building a shed. 

So Future Boiler, call your inspector & get him onboard:)