ECN Forum Forums Code Related Discussion NEC & other Code issues Commercial Range Hood - Residential Dwelling

what's the difference?

Type 1 commercial range hoods can take in grease.
Type 2 commercial range hoods cannot take in grease.
Both cover the entire top of the range, and are discharged directly to the exterior.
Residential range hoods aren't even required to be installed and do not usually cover the entire top of the range, and are not required to discharge outdoors (but they cannot discharge anywhere else except into your face).

As promised, I ran around town looking at some commercial range hoods, and took a few pics. Much to my astonishment, I encountered a few that actually appear to comply with the NEC!

This first one ... looks like I got there right after the cleaning guy ... has EMT to Appleton vapor-tights. In case you were wondering, the CFL's seem to work really well in this application:





Another restaurant also had EMT to the hood lights, with an extension to serve a stove-side receptacle:







Finally, her is a better view of the hood at that Chinese place:




Much to my surprise, the last hood looks to be in compliance. I was careful not to tell the owners that; I think they consider code compliance to be a mark of shame, and they would surely change it if they knew!

You can put a commercial range in a dwelling - it needs to be modified somewhat though. I believe you need to swap regulators and orifices. Or at least that is what they did before Wolf/SubZero made those pricey commercial look-a-like units. Then I think Wolf caught on and started making them that way. I have also seen one done that way recently that made it through all kinds of inspections to make sure it was converted. Only so much gas flow, etc.

Back on hoods.... You can custom build (as many commercial units are) any hood you like for a single family dwelling. With any appearance (commecial looking/rated if you like) or any acceptable CFM, and not have to follow the NEC for "Commercial Hoods" until the building is somehow re-zoned commercial. (By the way the NEC wrote it.) Otherwise it is just a "custom hood", and only need be listed if the AHJ wants it to be. Or at least that has been my experiance on it...

Did a bunch of reserch about this a few years back. (I wish I still had it, all I can find is the letter I wrote about it.) And from what I gathered that single family had relitively few restrictions... Multi-family had a few more in terms of listing requirements, and commecial had a rather wide range of requirement in all kinds of building codes.

Mark it is still a listing violtion to use commercial ranges in a dwelling unit.

The issue is not the gas flow but the fact that commercial ranges are not made to be installed into combustible construction. (Wood cabinets etc)

Perhaps some models have a duel listing but that is just a guess.

what I was wondering is why the doors in a house won't slam shut when these big hoods are turned on.
I always thought MUA was needed to prevent that from happening ...or you have air coming in thru every open window and leak

Because exterior home doors swing in and commercial doors swing out.

yes, thats right ..but there would still be a neg. pressure..
those hoods are more problems then they are worth...IMHO

Without a doubt and combine that with any fuel burning vented appliances (furnace, boilers, fireplaces) and you can have a real issue.

The typical old Florida house might whistle a bit but I doubt you would really generate any real vacuum. I have 2 big "whole house" fans that exhaust into the attic. Occasionally my kid would turn them on without opening any windows. You would think it would make your ears pop but it just demonstrated how leaky crank out "awning" windows really are. I can see it on my barometer tho. Sometimes the storm warning will go off from the rapid pressure drop.