I have spent the last two years boiling outside on a cinder block arch with steam table trays (~18 taps) and am looking to expand the operation this year to 50-75 taps (all sugars) and move the boiling into my pole barn which is insulated, but I'm unsure exactly how to set up the exhaust stack and the steam exhaust. The most taps I could see getting to is 100. I am looking at buying a 2x4 or 2x6 flat pan and welding up a homemade wood-fired arch. I am not currently planning on adding AOF or AUF, but could be convinced to if people feel it is really necessary. I have a homemade RO which I am running to ~4% (50% volume reduction). The barn is 32x28 with a 12' ceiling, shingle over OSB roof, the bottoms of the trusses have barn siding to form the ceiling (got the siding for scrap price and couldn't pass it up), with fiberglass insulation above the ceiling between the trusses.

My thought is to construct a steam hood for over the pan and route it out a window in the back of the barn. Do I need to add a fan to any part of the system? The bottom of the window is 45" above the floor and it is 30" tall, so it isn't very far up so are there any potential problems with the steam not going far enough up first? What types of materials should I use for the hood and for the ductwork to get it out the window? How high above the pans should I put the hood and how much overhang should I have?

As far as the firebox exhaust, every thing I've read says to go straight up through the roof and use a roof jack to get through the roof. What I am not sure of is what kind of insulation/double or triple wall stack pipe do I need to make sure I don't burn the building down? What kind of spacing do I need to run around the stack with the different configurations of stack insulation and wall setups both where I go through the ceiling and through the roof? Also, how high above the peak of the roof should I go? I see some people talking about sparks coming out of the stack and I really need to make sure I'm not burning the barn down.

Sorry for all of the questions, but I know that the price of learning the hard way is way too steep! Thanks in advance for the help!