Chimney extractor/exhaust fan

My brick oven build is nearly done, finally. The last piece of the puzzle is the chimney that actually exits the roof. Although I have confidence that the design, build and operation of the oven should ensure proper smoke extraction, since the oven is in my shop/restaurant and there's no typical kitchen exhaust system, I want to use the belt-and-suspenders approach and put an extractor fan in the chimney to ensure any anomalous smoke gets pulled up the chimney.

Trouble is, the recommended chimney fabricator/installer in town doesn't do these, and doesn't know where to get one.

Anybody have experience with something similar? This will be an 8" round double wall pipe, for the record.

You'd better look into the code implications of required exhaust and make-up intake air for a commercial establishment, if you haven't already. It's a lot more complicated than "make sure all the smoke gets out" these days.

Where are you located?

St. Louis. This has all been cleared by the engineering/design teams I've hired, and the plans - which have no exhaust fan of any kind anywhere in the building aside from the bathroom fart fans - have been approved by the city.

This is simply insurance and peace of mind for me.

OK, cool. I just hate to see people spend a lot of time and money, only to run afoul of the building inspector because they didn't know something ahead of time. Good luck!

A chimney should never need an exhaust fan, ever. Especially if it's a wood oven - soot can/will collect on the fan blades and eventually create a blockage.

There are draft inducers for some exhausts, but that is typically only for high efficiency gas furnances where the the exhaust path is long and exhaust temps are low and there may be an issue with the exhaust cooling in the flue before it reaches the end. For an oven, that should never be the case. As long as there is adequate make-up air, the heat of the exhaust will ensure it goes up and out the chimney.

What kind of oven? Commercial oven exhaust requirements can vary depending on the type. Some have direct flue connections, some are indirect. But if you had the plans done by an engineering company and they were approved, I wouldn't worry about it. There are pretty specific exhaust requirements in the code for commercial kitchens.

(In a past life I worked for a company that did engineering for commercial kitchens & supermarket prep areas)

My experience with chimneys is that they plug up with soot. Anything you put in there would seize solid, and unless it was completely removable you would not be able to clean the chimney. My dad tried something similar years ago and it is still lodged where it got stuck 30 years ago, and that stove hasn't really been used since. Also if the oven burns hot enough to cause the chimney to be self cleaning, how would the fan survive the heat? How about using a Y connection and pushing the air into the chimney remotely?