Commercial Cooking Recirculating Systems
Commercial Cooking Recirculating Systems
(OP)
I have searched the site and have come up empty. Any help would be appreciated as I would like some opinions on how to properly size the airflow to the situation below.
An island kiosk type structure is to be built in the middle of a large open room. The owner wants the room to be able to cook and prepare food, so of course there are fryers and possibly some convection ovens. The code allows for a recirculating system, as since this kiosk is in the middle of the room with no good way of routing exhaust duct, an normal kitchen exhaust system is not allowed.
Per the code, "Factory-built commercial cooking recirculating systems" shall not be required to comply with exhaust code requirements. "Spaces in which these systems are located shall be considered to be kitchens and shall be ventilated" per ventilation table. "For the purpose of determining the floor area required to be ventilated, each individual appliance shall be considered as occupying not less than 100 sq. ft."
Now the ventilation table for kitchens only includes an exhaust flow rate, and using that last line of the code (2 fryers, 2 convection ovens) the square footage to determine airflow shall be 400 sq. ft. (though the actual space is less than that). At 0.7 cfm per sq. ft. required exhaust, 280 cfm is required. But with this being a recirc hood system, is this now the required OA?
This is where I'm getting hung up. The code states that recirc hood systems don't need to exhaust the air, but the ventilation schedule requires it. Does this code allow for indirect exhaust? Where the hood doesn't need to be exhausted but the room does?
Another problem arises with getting supply air to the room. An electrical closet in this space is situated away from the wall too, but a supply fan blows air from the building into the space, in an indirect supply fashion. Is this a possibility for supplying air into the kitchen?
I'm at the beginning of the design and am looking for some people with experience that may be able to help or offer solutions that I haven't thought of yet. The space is located in Michigan, and while they have their own code, it is based off of IMC 2012.
An island kiosk type structure is to be built in the middle of a large open room. The owner wants the room to be able to cook and prepare food, so of course there are fryers and possibly some convection ovens. The code allows for a recirculating system, as since this kiosk is in the middle of the room with no good way of routing exhaust duct, an normal kitchen exhaust system is not allowed.
Per the code, "Factory-built commercial cooking recirculating systems" shall not be required to comply with exhaust code requirements. "Spaces in which these systems are located shall be considered to be kitchens and shall be ventilated" per ventilation table. "For the purpose of determining the floor area required to be ventilated, each individual appliance shall be considered as occupying not less than 100 sq. ft."
Now the ventilation table for kitchens only includes an exhaust flow rate, and using that last line of the code (2 fryers, 2 convection ovens) the square footage to determine airflow shall be 400 sq. ft. (though the actual space is less than that). At 0.7 cfm per sq. ft. required exhaust, 280 cfm is required. But with this being a recirc hood system, is this now the required OA?
This is where I'm getting hung up. The code states that recirc hood systems don't need to exhaust the air, but the ventilation schedule requires it. Does this code allow for indirect exhaust? Where the hood doesn't need to be exhausted but the room does?
Another problem arises with getting supply air to the room. An electrical closet in this space is situated away from the wall too, but a supply fan blows air from the building into the space, in an indirect supply fashion. Is this a possibility for supplying air into the kitchen?
I'm at the beginning of the design and am looking for some people with experience that may be able to help or offer solutions that I haven't thought of yet. The space is located in Michigan, and while they have their own code, it is based off of IMC 2012.





RE: Commercial Cooking Recirculating Systems
Unless their business model is to attract patrons by making the entire building smell like food.
you can use transfer air to make up for the exhaust
RE: Commercial Cooking Recirculating Systems
I appreciate the help in understanding the issue.
RE: Commercial Cooking Recirculating Systems
RE: Commercial Cooking Recirculating Systems
RE: Commercial Cooking Recirculating Systems
RE: Commercial Cooking Recirculating Systems
B.E.
You are judged not by what you know, but by what you can do.
RE: Commercial Cooking Recirculating Systems
What I would proposed is a push-pull ventilation system for the kiosk that way you'll save on air conditioning and heating of the restaurant.
RE: Commercial Cooking Recirculating Systems
Attached web link may be of use:
http://fishnick.com/
RE: Commercial Cooking Recirculating Systems
Almost all states will require a hood system with tempered make-up air, with exhaust flowing through hood filters to the outside of the building. The system must be tuned for slight negative pressure in the kitchen, so that kitchen air cannot exfiltrate to the customer area. You should be able to get a copy of a "Foodservice Construction Guide" from the health department or other regulating agency in your locale. The aforementioned NFPA guide is also a must-see, as is consultation with the insurance company. Any system will require built-in automatic fire suppression, as well, and a documented cleaning schedule.
Don't ignore plumbing requirements, either. There are some unique aspects in food service establishments.
Good luck!
It is better to have enough ideas for some of them to be wrong, than to be always right by having no ideas at all.
RE: Commercial Cooking Recirculating Systems
The kitchen will be exhausted at 0.7 cfm/sf with the provision of upping the square footage for each piece of equipment under the hood (the room is 330 sf, but we need to use 500 sf for exhaust calculations per code). Make-up air will be provided to the space the kitchen is installed in and transfer air from outside will flow into the kitchen, keeping the kitchen negatively pressurized.
Plumbing will be a pain, but we are still waiting on information from the kitchen consultant. Yes, one is on board, and they are the one specifying the recirc hood.
I'm not a fan of the recirc hood, but the client wants it, so I'm doing my best to make this kitchen operate as well as I can.