chimney/flu

[hewynz]

hey, im new zealand, buliding a large pompeii oven for a restaurant, construction starts in a month.. but i was wonder wether there would be any specifics about my flu/chimney. im having a cooking surface of about 1.8meteres in diameter and my flu has to go up three floors high, would i need a small suction fan or is there anythinng i have to do so it will flow properly..??
thanks
james

[michael]

Re: chimney/flu

Hello James

While in Napoli doing my pizzaiolo training I was interested in seeing how other people dealt with the flue issue. Logic tells me I need everything pointing up for a natural draw of heat, but can I have any horizontal run if obstacles exist? James, I saw everthing while researching pizzerie in Italy. Most flue systems exited the oven at 90 degrees then took a 30 degree turn through a wall and then straight up. The place I did my training had the oven in the middle of the dining room and after exiting the oven it took a 5 meter horizontal exit through the DR and then the prep area, passed through a "water bath" exhaust cleaning system (fantastic little device), exited the building, did another 10 meter horizontal run then went straight up an eight story apartment building to the roof. All of this without the aid of any mechanical air handleing device. Amazing!

My only other first hand experience was in Athens where a client I was helping put a Forno Bravo Ristorante 140 on the middle floor of a three story 1830's neo-classical Greek building, we took a 30 degree turn out of the oven, then through a concrete wall, then a 90 degree turn straight up an old elevator shaft and through the roof. Local regulations stipulated that the chimney cap be 2 meters above the hightest point of the roof. I'm happy to say everything worked perfectly!

I know I've contradicted myself, but that was the point, I've seen a lot of different configurations and they all seem to work. What does your local ventilation guy have to say?

I'd be very interested to hear from other commercial installs to find out if any nightmares exist.

[Xabia Jim]

Re: chimney/flu

As an amature mason but avid pyromaniac I've dealt with a lot of different chimneys.

Once the chimney is operating (hot and dry) and you have the "chimney effect" going smoke is pulled out by the rising heat. You need a good vertical run to get the chimney effect going and you need sufficient return air to the fire. (like an open window in a house)

I think Michaels comments show that you can have long horizontal runs as long as they are tied into good vertical runs. I also think that piping (smooth walls) is better for commercial operations and that the biggest problem would be undersizing the flue.

I do note that my oven smokes too much and I plan to add more of a vertical rise in my chimney to get better performance.

One last comment....I did see a pizza oven in a restaurant in Spain that had a hood over the chimney. It had a large inverted saucer over the open chimney and this connected into a metal chimney. I think it was a fan operated unit. Looked interesting....sorry I didn't take a picture!