Need help about point of discharge of exhaust gases (huge building generator)

[Lnewqban]

Just wanted to ask here about a situation that is new to me.

Do you know where could I find information about restrictions or guidance for location of discharge of exhaust gases for a huge Diesel generator?

The application is a new Assisted Living Facilities in Florida.
Original design specified a vertical 6-inch duct ending above the roof level (two-story building).

Contractor decided discharging the gases about 12-foot above grade (parking lot) and 4-foot from face of building (which has no open-able windows or door nearby).
I cannot find anything in the 2012 mechanical code (year of original design), besides the 10-foot separation from intakes and the monoxide detector inside the building that contains the engine (huge V-12 Diesel engine).

The concern is noise, smoke and wind-driven infiltration of monoxide for long periods of power outages, like after hurricanes.

Grateful of any contribution.

"Where the spirit does not work with the hand, there is no art." - Leonardo da Vinci

 

[chicopee]

"Do you know where could I find information about restrictions or guidance for location of discharge of exhaust gases for a huge Diesel generator" What does the local municipal regulation or the State Fire Marshal say?
I sure would not want the stack to discharge in front of no "open-able" windows because what would happened if one of these windows broke during a storm?

 

[Lnewqban]

Local regulations and authorities have no clear position about this situation, which is the reason to my question.
Florida building code refers to Fire code, where we have not found any specific guidelines.

"Where the spirit does not work with the hand, there is no art." - Leonardo da Vinci

 

[PEDARRIN2]

Does the code reference NFPA 31, 37 and/or 110?

If so, then those may be off assistance.

 

[dbill74]

You will be fine so long as you meet 10 feet clearance requirements of FMC.
Going through the wall versus through a second floor (assuming the generator is on the first floor) is much easier and avoids a lot of complex construction to protect the exhaust pipe.

 

[SandCounter]

You may want to look at engine exhaust nozzles. They take up some room but they jet the exhaust out at high velocity.
I won't link to a particular brand on the forum, but here is a link to the patent. [URL unfurl="true"]https://patents.google.com/patent/US7707828[/url]

I used to count sand. Now I don't count at all.

 

[chicopee]

In addition to the concern that I mentioned above, there is also the issue of noise from the exhaust gases. I would prefer the outlet to be well above the roof line.

 

[GT-EGR]

For your question about flue exhaust termination requirements - Florida mechanical code likely has a chapter on chimneys and vents. Find which type of vent your equipment falls under and it will give you height and separation requirements. Some municipalities have their own checklist specific to generator installations and all of these that I've seen require you to meet NFPA 37. In NFPA 37 it has guidance on separation from combustible walls, building openings, etc, which may be similar to the chimney and vents section (NFPA 37 covers a lot more than just venting). I think you'll find the installation you described does not meet mechanical code or NFPA 37 separation requirements.

Also worth mentioning that meeting code doesn't necessarily guarantee that you won't get any smoke or CO into the building, you have to do some CFD modeling to be more confident of that, but for the most part it's a pretty healthy separation, and you should try to keep your discharge as far away from everything as reasonably possible.

The sound question usually comes down to local ordinances, some are very clear and some are hard to come by. You have to find the acceptable noise levels at specified distances from property lines, and then attenuate your engine noise to stay below that. The ordinance usually gives you constant noise limits and intermittent noise limits, but if the generator could potentially be on for emergency purposes for a while, than it's a constant noise and has to be treated as such.

Local ordinance means looking up the county or city the project is located in, and they should have a list of adopted codes and permitting guidelines. And hopefully somewhere in there you find this document. If it truly doesn't exist, you should find something from a nearby town or county so you can at least point to that and say you met that criteria. Sometimes picking up phone and calling the building dept gets you more information than you would think.

 

[Artisi]

Suggest asking the engine supplier for a list of similar installations allowing you to ask questions etc of the end user and their design engineers - ask about problems, suitability from local authorities etc.

It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)