With regard to code for deep fryer placement in a commercial kitchen, refer to the National Fire Protection Assosication: NFPA 96 12.1.2.4 All deep fat fryers shall be installed with at least a 406-mm (16-in.) space between the fryer and surface flames from adjacent cooking equipment. I'm not claiming that this regulation is in building codes in all areas but it is a guideline. In my experience many inspectors will site "outside" sources such as these if local codes are not clear about requirements. Also keep in mind that if this is a commercial fryer unit, it may not meet safety requirements to be installed in a residential location. If you are building under permit, best to get all of this signed off by the planning department with specifics so that inspectors won't apply their own interpretation of code after you've already committed thousands of dollars to a certain configuration or plan. Good luck.

@sarina: I have had the Kobe RA02 for about 8 months now. Being an engineer, I did the install myself, although the chimney cover is still not in place, as I need to redo the crown molding behind it (procrastination is the name of this game). Overall I like it, but that doesn't say much, as my previous ventilation was just a fan-in-a-ceiling-hole. The quiet setting is quiet, but the other two are noisy; without previous experience, the "sones" numbers don't translate well into actual noise levels. Otherwise, on High, the hood is pulling out all the smoke and airborne grease steaks in a cast-iron skillet produce. You will have to open a window or install a MUA to help it pull all that air volume. The baffles need scrubbing every month or so, but that's a very small price to pay for not having cabinetry and walls smeared in grease. The model you're looking at is a little more elaborate, as it has some sort of electronic control. The RA02 is bare-bones, just two rotary switches.

A guy in my daughter's HOA tried to "ban" my vehicle from parking anywhere in the community other than inside DD's garage because it was an "eyesore." It was an inexpensive Ford, about 10 years old, but no dings, dents, or dirt anywhere. He was over ruled and forced to apologize to me, wherein he mentioned a couple of times how angry his wife was at him, haha! The last HOA community I lived in made us fix two shingles that appeared (to them) to be "out of alignment." Oh, did I mention it was the roof of our DOG HOUSE? Never again. Never. Again. Onto the topic at hand. I currently have a vented hood of indeterminate brand. I'm pretty sure it's the original hood in my 37 yr old home, and I'm positive it's never been cleaned (until I moved in). If you recall, I bought this house from hoarders who never, ever cleaned their house. Even after I paid people to clean the whole range (electric coil stovetop), including the hood, it is the most vile, disgusting thing I've ever seen. It's also frighteningly loud. I'm certain it doesn't pull up anything; not grease, not odors, nothing. When I remodel the kitchen, I'll most likely stay with a vented hood since there's already the hole in the roof. I would reconsider if there wasn't a way to use the same hole. I know this topic has been passionately argued over for years on this forum. And I mean passionate! But I've had the recirculating vents before and, at least in my case, have found them adequate (please don't execute me at dawn for saying that!). There are a couple of secrets to keep them working well, and I assume this would also apply to OTR recirculating micros. First, many of them recirculate the air through a charcoal filter. You have to replace that filter once in a while! :-) Just like furnace or A/C filters, if you never replace them, they get dirty and cease to clean the air; in fact, they make it worse after a while. Second, while you're at it, go ahead and clean the other parts too. If you rent, make the management replace the filter when it's due. For now, my "vent" is the two windows in my kitchen. I happen to think my cooking smells good, so the windows are basically to keep a very sensitive smoke alarm from going off. Russ, where can I order one of those pot roast pillows?

Heh! Yes, mattress is a very good example. This is why ca. 2007 I started reading up on kitchen ventilation so I could ignore the magic that was being asserted and determine for myself what was needed. In a hood, most of the effectiveness is embedded in the sheetmetal shapes and the blower motor and fan. I rarely hear of fan failures (I can only recall one on this forum). Broan absorbed NuTone that used to provide a lifetime guarantee. Wolf uses Broan. If the hood exterior is non-magnetic stainless steel, it shouldn't ever rust or develop surface staining. What tends to fail in lower quality hoods are fan and light switches. These hoods may have thinner sheet metal, but that is not a point of failure. It might have a relationship with rattles. Mean time to failure with electronics will typically decrease with increased parts count. So some risk of shorter lifetime may be present where fancy motor control circuits are in use. It is fine to go shopping and look at hoods from the point of view of ease of use or lighting or construction quality, or aesthetics of design, but nothing should be purchased until you have gone through the process of understanding what you need a hood system to do and what its parameters have to be to achieve it. Since modern higher performance residential hoods for pro-style cooking equipment derive their requirements from commercial cooking ventilation, you may wish to start by downloading and reading the first dozen or so pages of the Greenheck Guide: https://www.tagengineering.ca/wp-content/uploads/2015/02/KVSApplDesign_catalog.pdf