Back up generator distance for exhaust to building opening

[Mike Pearson]

What is the current required distance for permanently mounted and hard wired, auxiliary back up gas generator, distance for the exhaust to building openings in Florida. Also, which I know is not a problem for you the code reference. I have always called out 10 feet now getting push back from generator company and not sure on the specific code ....not what " most manufactures recommend" BS
As always for the last 21 years
Thanks Jerry
Mike

[Jerry Peck - Codeman]

The clearance from internal combustion engine exhaust has been 5 feet for a long time, but ...

But ... the big "but" ... for a number of years, the wording was such that, with equipment such as optional standby generators (that is the correct term to use as it is "optional", versus "legally required" standby generators) which as typically air cooled, and which the exhaust is typically discharged into the cooling air stream, creating "diluted air" (you see where this is going) ...

And the discussion was: all outdoor air is "diluted" air as it is diluted with everything in the outdoor air (diluted with internal combustion exhaust from lawn mowers, cars,, trucks etc) ... thus either *all* "diluted" outdoor air must have a required minimum clearance from building openings ... as though that is even possible ... or the "diluted" air from optional standby generators should be treated the same as other "diluted" outdoor air (no clearance requirements).

Different AHJ discussed that in different ways. Many (most?) going with (if the manufacturer's installation instructions did not include a drawing showing what they wanted) something to the effect of '5 feet from the internal combustion exhaust discharge' (the end of factory exhaust pipe), which was what the wording was going for.

I'll look for it later today, but I believe I have an email with 'current' recommendation requirements which show 5 feet clearance from the closest cabinet enclosure side/end/corner to building openings.

I'll post it here when I find it.

But ... another "but" ... if you go with 5 feet to the closest part of the cabinet enclosure, I suspect you won't get any complaints, and, if you do, you already know the answer to respond with: "What does the manufacturer's installation instructions say?"

If they can't produce the manufacturer's installation instructions, they have no documentation to argue from (neither do you, but if they don't accept your 5 feet, it is up to them to document it is different ... and once you get documentation, providing it in your report will support what you say - I'll see what I have).

[Jerry Peck - Codeman]

Mike,

This is from an email with some Building Officials when we were discussing some of the issues you are asking about - here is a link to the Generac optional standby whole house generator manufacturer's installation instructions:
https://soa.generac.com/manuals/3001694932/0L6630

Scroll down to page 11 (file page 15 of 52) for Section 3: Site Selection and Preparation, see items C, D, E and G in the drawing and the table below. There is text on the following page which puts it is writing.

The code reference, though, is, I am sure, one you already have.
- Florida Building Code, Fuel Gas: (bold and underlining are mine)
- - SECTION305 (IFGC)
- - - INSTALLATION
- - - - 305.1 General.
- - - - - Equipment and appliances shall be installed as required by the terms of their approval, in accordance with the conditions of listing, the manufacturer’s instructions and this code. Manufacturers’ installation instructions shall be available on the job site at the time of inspection. Where a code provision is less restrictive than the conditions of the listing of the equipment or appliance or the manufacturer’s installation instructions, the conditions of the listing and the manufacturer’s installation instructions shall apply.
- - - - - - Unlisted appliances approved in accordance with Section 301.3 shall be limited to uses recommended by the manufacturer and shall be installed in accordance with the manufacturer’s instructions, the provisions of this code and the requirements determined by the code official.