Ducting Systems and Air Ventilation - Ducts for commercial oven

I want to run some ducts for our commercial bake oven. My local heating and cooling company told me that since we are only baking cakes, breads, and such, that we do not need B5 vent and we could use just regular vent pipe. I will run the 8" piece from the hood to an elbow, run an 8" to 6" reducer and then straight pipe it to and out the wall with the end peice. Do I need to extend it past the siding and out from the wall a foot or so, or can I mount the outside peice tight to the vinyl siding? If I have to go out past the siding, what do I use to seal around the 6" pipe coming through the wall?

I want to run some ducts for our commercial bake oven. My local heating and cooling company told me that since we are only baking cakes, breads, and such, that we do not need B5 vent and we could use just regular vent pipe. I will run the 8" piece from the hood to an elbow, run an 8" to 6" reducer and then straight pipe it to and out the wall with the end peice. Do I need to extend it past the siding and out from the wall a foot or so, or can I mount the outside peice tight to the vinyl siding? If I have to go out past the siding, what do I use to seal around the 6" pipe coming through the wall?

Being a commercial application local codes apply :coffee:

When make and model is your oven and is it gas or electric?

In order for your oven to meet approvals they have to provide installation instructions and for the installation to be approved you need to follow them.
Without knowing what the requirements are both code and instruction wise I don't think anyone here could give you any accurate advice.