Thread: Recirculating range hood over gas range

Just wanting to get a little more information on gas range ventilation. Todays inspection had a recirculating range hood over the gas range. I know that this is not recommended, but was wondering if I should call it out as a potential safety concern or not. I will be recommending a CO detector to be installed.

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I think I recall this being tossed around once before... As I remember, there's nothing specifically prohibiting it. I agree it's not the best idea. I usually do the same as you propose in mentioning it and recommending a CO detector.

I think the theory behind it is that a range is not a constant use device like a furance or fireplace. Most people don't sleep with the range on. Of course, one could fall asleep but, hopefully, they'll wake up because they're hungry before they die.

I also remember something about one state or association requiring this being called out as a defect.

You might have some luck doing a search or I'm sure someone else will chime in.

Trent,

The only thing that I might add is that there might be a range manufacturer that requires a vented hood. Not sure, but I think that commercial ranges require a vented hood. If so, the Wolf, Viking and other "professional" ranges might also.

[quote=Gunnar Alquist;65707]Not sure, but I think that commercial ranges require a vented hood.[quote]

"Commercial" ranges do, and the hood also requires an extinguishing system, grease filters, and other things.

"Commercial" ranges *are not allowed* to be used in dwelling units.

If so, the Wolf, Viking and other "professional" ranges might also.

All of the "professional" ranges (with "professional" not being "commercial") do require big monstrous hoods (I believe at least 6" to each side of the range, minimum and maximum heights above the range, minimum cfm extraction, etc.), at least to my knowledge and recollection having read many of their installation instructions.

Very common. I do not understand why buyers don't insist that the device be vented to the outside of the home. The fan serves no purpose not being vented.

Originally Posted by JORY LANNES

Very common. I do not understand why buyers don't insist that the device be vented to the outside of the home. The fan serves no purpose not being vented.

"The fan serves no purpose not being vented."

Actually, the fan does serve a purpose in recirculating range hoods, a similar purpose to what they serve in hoods which exhaust to the outdoors.

In hoods which exhaust to the outdoors, the fan draws the air through a grease filter of sorts (to catch grease), then exhausted outdoors (to remove odors), with fresh outdoor air being sucked into the now negatively pressured house.

In hoods which are recirculating types, the fan draws the air through a grease filter of sorts (to catch grease), then through a charcoal filter (to remove odors), then ... blown back into your face (I guess so you can tell the fan is working ), this does not negatively pressurize the house, so no fresh outdoor air is sucked in.

With recirculating range hoods, some of us taller folks who wear glasses sometimes need miniature wipers on our glasses.

this is a joke .........Right??

Originally Posted by Richard Pultar

this is a joke .........Right??

A particular post?

The entire thread?

The whole board?

Something you have on TV as you type?

Care to be a bit more specific?

the thread

Originally Posted by Jerry Peck

Originally Posted by Gunnar Alquist

Not sure, but I think that commercial ranges require a vented hood.

"Commercial" ranges do, and the hood also requires an extinguishing system, grease filters, and other things.

"Commercial" ranges *are not allowed* to be used in dwelling units.

All of the "professional" ranges (with "professional" not being "commercial") do require big monstrous hoods (I believe at least 6" to each side of the range, minimum and maximum heights above the range, minimum cfm extraction, etc.), at least to my knowledge and recollection having read many of their installation instructions.

Y'know, I thought that too but, out of curiosity, I pulled out the documentation for my own 48" Dacor. Nothing. I then searched the Dacor, Wolf and Viking on-line user and install manuals and couldn't find anything more than some rather lame "recommendations" to use a hood. Wolf, for instance recommends one of their hoods but then also gives clearances for installing a range without a hood at all. Viking sells recirculating conversion kits (charcoal canisters) for their range hoods.

Jerry, I have to say I'm surprised. I was also fully expecting to find something more along the lines of a "requirement". Of course, even if such requirements existed, none of the hoods or exhaust systems I've ever seen come on automatically with the ranges or cooktops, and so I guess the hazard would still there despite being ducted to the exterior or not.

"Trent: I will be recommending a CO detector to be installed."
Very good idea!!

This is along the same line as you guys are talking about I installed a gas grill in a home .Grill manufactor recommend a exhaust hood if used in doors . My question is why don't they recommend a exhaust hood over a gas stove? Still cooking with gas .

The answer is "THE DEATH OF COMMON SEANCE"

Richard,

All I can do is recall the countless times I've had that discussion with builders, who would then produce the installation instructions to back them up, only to have the installation show the specifics for the hood requirements.

Also, if the wall behind is not rated for a specific temperature, a deflector needs to be installed, same or peninsula and island installs where there was no wall behind it.

I'll try to see if I can track something down.

I noticed the revision date on the Wolf installation instructions was 10-2006, looks like they have made some changes since I last inspected one. Looks they they "dumbed them down" so they could compete more readily with the lower tier manufacturers, although they still have that 12" back requirement for peninsula and island installations.

Originally Posted by Trent Tarter

Just wanting to get a little more information on gas range ventilation. Todays inspection had a recirculating range hood over the gas range. I know that this is not recommended, but was wondering if I should call it out as a potential safety concern or not. I will be recommending a CO detector to be installed.

For what it's worth, 75 to 80% of kitchens have a gas range with recirculating range hood.
I feel that calling it a safety issue makes you look like an alarmist.
The "real" pupose of the recirc type range hoods is to protect the wood cabinets above them from catching on fire from the stove.
I usually put in a red to clean the filters peridocally.
Hope this helps.

Originally Posted by Ira Eisenstein

I feel that calling it a safety issue makes you look like an alarmist.

I never minded that, my clients understood what I was reporting and why, and they quickly understood who "their" agent was really working for when "their" agent started calling me "alarmist".

The "real" purpose of the recirc type range hoods is to protect the wood cabinets above them from catching on fire from the stove.

Actually, placing a plain metal surface under the wood cabinets does very little to protect the wood cabinets, that does not allow for any reduction in clearance, etc.

The "real" purpose of those hoods is to catch the grease laden air and remove as much grease as possible from it. It is the build-up of grease which makes a small fire into a very big fire very quickly.

Keep in mind that if you use a large hood (high CFM) you would need to allow for make-up air. I have seen many oversized hoods that can place a house under negative pressure better than a blower door.
In a commercial setting the hood and makeup air units operate at the same time. They have to be balanced so they do not pull air from the HVAC of the rest of the building.

These hoods can often be the cause of fireplaces smoking as well. If I start a fire in my woodstove with the door open and turn on my kitchen fan at the other end of the house it smokes, turn it off and it stops.

People always think there's something wrong with their fireplace.

Originally Posted by Matt Fellman

These hoods can often be the cause of fireplaces smoking as well. If I start a fire in my woodstove with the door open and turn on my kitchen fan at the other end of the house it smokes, turn it off and it stops.

People always think there's something wrong with their fireplace.

Matt,

Think what that kitchen exhaust fan is doing to your other combustion appliances. Talk about backdrafting and CO being pulled back into the house ...

Originally Posted by Matt Fellman

These hoods can often be the cause of fireplaces smoking as well. If I start a fire in my woodstove with the door open and turn on my kitchen fan at the other end of the house it smokes, turn it off and it stops.

People always think there's something wrong with their fireplace.

A very good point for those hoods that vent outside.
A recirculating hood shouldn't cause a woodstove or fireplace to do that, as it pulls air from below and blows it right back out the top.

Originally Posted by Jerry Peck

Matt,

Think what that kitchen exhaust fan is doing to your other combustion appliances. Talk about backdrafting and CO being pulled back into the house ...

A valid point if the exhaust fan is a vent-outside fan. (a recirculating one does not change the pressure in the house)
So then the same logic applies to dryer vents and bathroom exhaust vents and whole house fans and under some circumstances, powered attic exhaust fans.
Yet most houses built in the last 30 or so years have some or all of these things.
Do we tell people not to use them?

Originally Posted by Ira Eisenstein

A valid point if the exhaust fan is a vent-outside fan. (a recirculating one does not change the pressure in the house)

.

That's why I called it an "exhaust fan" instead of a "ventless" or "recirculating" range hood.

So then the same logic applies to dryer vents

.

Correct.

and bathroom exhaust vents

.

Most bathroom exhaust fans are not powerful enough to create much of a problem, besides not being powerful, few people even turn them on (other than HIs inspecting them ).

and whole house fans

.

Absolutely! Those *are designed to suck the air out of the house and draw outside air in, and they do a dang good job of it too. Those things will such the air right down the vent and back into the house.

and under some circumstances, powered attic exhaust fans.

.

Correct again.

Yet most houses built in the last 30 or so years have some or all of these things.

.

Not from where I have been. Those were in the 1960s and older homes, once a/c came in, people closed the houses up.

Do we tell people not to use them?

.

I always did. And explained why.

H ey guys I'm getting a little confused now. The original poster was concerned that the range only had a recirculating range hood and I believe its gone from the recirculator being a possible call-out item, to it being the prefered method of use. Jerry your saying you would tell your clients the range hood should not exhaust to the outdoors. Is that right? Have you ever come across a home with a system for make up air that was specific to the range hood? Thanks

Originally Posted by Brian Robertson

H ey guys I'm getting a little confused now. The original poster was concerned that the range only had a recirculating range hood and I believe its gone from the recirculator being a possible call-out item, to it being the prefered method of use. Jerry your saying you would tell your clients the range hood should not exhaust to the outdoors. Is that right? Have you ever come across a home with a system for make up air that was specific to the range hood? Thanks

I think the thread drifted into just a discussion of characteristics for both types of fans. There's nothing wrong with either type as both are generally allowed and widely used.

I always insert in my report if a range hood is vented or not.

and if the fan is working.

"It is standard to pair a range hood that vents to the exterior of the home with a gas range/oven. The installed hood recirculates air through a filter and back into the living space. Gas produces primarily water and carbon dioxide when burned completely. Incomplete combustion can produce toxic carbon monoxide. Although not required, a range exhaust hood vented outside will reduce the risk of carbon monoxide poisoning. Some recommend the use of carbon monoxide sensors in kitchens with gas appliances, or operate the appliance as with any unvented gas appliance with a nearby window partially open for safety."

If there are other moisture-venting issues in the home such as mold on window sashes or mildew on the ceiling in the dining room, then I'll recommend changing to an exterior venting hood, or limit the amount of spaghetti and macaroni you're boiling.

Originally Posted by Brian Robertson

H ey guys I'm getting a little confused now. The original poster was concerned that the range only had a recirculating range hood and I believe its gone from the recirculator being a possible call-out item, to it being the prefered method of use.

.

Nope. The exhaust-to-the-outdoors is preferred.

Jerry your saying you would tell your clients the range hood should not exhaust to the outdoors. Is that right?

.

Nope, not right.

Exhausting to the outdoors is preferred, BUT ... when there are fuel burning appliances in the house, one must make sure that there is sufficient make up air provided for, and in a location which will provide that make up air before the exhaust draws the air from the other end of the house.

Have you ever come across a home with a system for make up air that was specific to the range hood?

.

Unfortunately, no.

Fortunately, the heaters were either all electric strip heat (the majority in South Florida) or heat pump (like our is up here) with back up electric strip heating, and, the water heaters where in the garage (in most cases).

That removes the negative pressure versus backdrafting problems, however, it does not remove the negative pressure versus air infiltration problems.

Hello,
I found this thread while searching the internet for information on kitchen ventilation. I have replaced my 16 year old 4 burner natural gas cooktop with downdraft with a 5 burner natural gas cooktop without a downdraft. I would not consider the cooktop a large/commerical style cooktop. I wanted some sort of ventilation and I chose a hood vent since it doesn't seem like there would be enough room to add a telescoping downdraft behind the cooktop. After reviewing I found it would basically not be possible to add new ductwork for the hood vent and I was told connecting to the existing ductwork for the downdraft wouldn't work (vent hood would not be strong enough to connect to the downdraft and also to connect to existing downdraft would require 3 elbows and about 8ft. of additional ductork). The hood vent can be converted to a recirculating model though. From what I was told, a recirulating hood vent works fine as long as you keep up with cleaning the grease catching mesh filters/gills as well as the charcoal filters. A salesperson told me that they felt that other than maintaining the filters, the only negative is the re-circulated air would still be warm and have all the moisture in the air. So is it really that ineffective to use a recirculating system, and also could I have the vent connect to the adjacent garage instead of recirculating into the kitchen?

Originally Posted by Chris Regacho

After reviewing I found it would basically not be possible to add new ductwork for the hood vent and I was told connecting to the existing ductwork for the downdraft wouldn't work (vent hood would not be strong enough to connect to the downdraft and also to connect to existing downdraft would require 3 elbows and about 8ft. of additional ductork).

"Basically not be possible"?

Is that because the vent fan is not powerful enough, or, because 'it is not possible' to add the duct work?

From your post, I'm reading is as 'it would be difficult, but not impossible, to add the duct work'. Is that correct?

If so, consider installing an external outdoors exhaust fan on the far end of the original downdraft duct work (first making sure that the downdraft duct work is in good condition.

Many range hoods are adaptable (within their listing) to an external mounted exhaust fan.

Not only will this allow a more powerful exhaust fan to be use, but now the exhaust fan noise will all be outdoors, not in the kitchen, leading to a much quieter kitchen environment.

Of course, once you increase the cfm of the exhaust fan beyond that in the old downdraft, you may need to consider allowing for more make-up air from outside (depends on the house and how tight it is). Provided you did not have any unknown problems with the existing cfm of the old downdraft, if you did, it would complicate it with the higher cfm of the new exhaust fan.

I prefer exhausting cooking odors, etc., to the outdoors, however, I also have not had to worry about having backdrafting problems for gas appliances, fireplaces, etc., when I did have an exhausting-to-the-outdoors range hood.

Do not discharge the vent into the adjacent garage.

Jerry,
Thanks for the quick reply.

"Basically not be possible"?
Is that because the vent fan is not powerful enough, or, because 'it is not possible' to add the duct work?

The fan is rated at 340CFM. Based on the location of the hood, to do new ductwork would involve either having a vent on the front of the house (which is brick) or possibly on the roof of the house in the front. Either situation would involve 3 90 degree elbows and about 15 ft of ductwork.

From your post, I'm reading is as 'it would be difficult, but not impossible, to add the duct work'. Is that correct?

Yes. To connect to the existing ductwork would involve 3 90 degree elbows. 2 of the elbows would be basically connected creating a 180 degree turn right at the exit of the vent hood. It would then run down between the wall studs about 7 feet of 3.25x10 rectangular ducting into a 90 degree elbow which would then connect to the existing downdraft ductwork which runs about 15 feet and has 2 45 degree turns.

If so, consider installing an external outdoors exhaust fan on the far end of the original downdraft duct work (first making sure that the downdraft duct work is in good condition.

A contractor said that an fan could be added to the other end of the downdraft venting but he still does not like the idea of having 3 90 degree elbows and 7 feet of ductwork connecting to the existing downdraft.

I'm considering setting it up for recirculating for now and later on doing new ductwork to connect to the roof on the front of the house. So far from what I gathered it wouldn't be good to connect to the existing downdraft ductwork and it would not be code to exhaust into the garage...even if I do use the recirculating kit. Also in regards to recirculating....I have heard most people say they don't work whereas others have said they do a great job as long as the filters are changed out periodically. Anyone have any first hand experience with recirculating vent hoods?

Any other additional advice/suggestions would be appreciated!

At one point you mentioned ducting into the garage, if that is possible, why not just run the duct into the garage, through the garage (along the wall/ceiling), then out the side of the garage?

Feasible?

Seems like it would be a lot less work than going up through the roof (any roof penetration is a likely roof leak and should be considered as such - i.e., if you do not need to, do not go through the roof).

Originally Posted by Jerry Peck

At one point you mentioned ducting into the garage, if that is possible, why not just run the duct into the garage, through the garage (along the wall/ceiling), then out the side of the garage?

Feasible?

Seems like it would be a lot less work than going up through the roof (any roof penetration is a likely roof leak and should be considered as such - i.e., if you do not need to, do not go through the roof).

One side of the garage is the front of the house, based on how the home is positioned the front side of the garage is also easily visible from the front of the house. The other side does not connect to the outside (laundry room) The closest run would be the front of the house which would involve punching through brick and also having a vent on the front of the house wouldn't be appealing.

Someone else suggested running an inline duct booster. They look to be less than $40 but its rated at 160 CFM.

Originally Posted by Chris Regacho

Someone else suggested running an inline duct booster. They look to be less than $40 but its rated at 160 CFM.

But are likely NOT rated or approved for use with grease laden air, which is what you would be using it for.

So a low cost in-line booster wouldn't be an option - it might work but it wouldn't be code.

So if I want to use the vent hood my options are:

1) Connect to existing ductwork while also using an inline outdoor exhaust fan
2) New ductwork that would connect to the front of the house
3) Recirculate - which most say don't work (though others say they work fine)

With cost being a concern, I'm guessing recirculating is the best option?

Though I'm not completely against returning the hood vent and/or cooktop and get a downdraft cooktop or a telescoping rear downdraft it doesn't seem like they would work that well since the vent is on the cooktop itself or slightly above if its a telescoping. My experience using a downdrafts so far show that they are too low and only catch a fraction of whatever is being cooked. Also using a downdraft with a gas burning cooktop seems to pull away from the burners....

Originally Posted by Chris Regacho

So a low cost in-line booster wouldn't be an option - it might work but it wouldn't be code.

More importantly, it may catch on fire ... which would be why it would not meet code.

Do not use ANY in-line booster unless it is rated for grease laden air handling, REGARDLESS of price (and I am not aware of any in-line booster fan which is rated for grease laden air).

So if I want to use the vent hood my options are:

1) Connect to existing ductwork while also using an inline outdoor exhaust fan
2) New ductwork that would connect to the front of the house
3) Recirculate - which most say don't work (though others say they work fine)

I would not say that recirculating fans "don't work", but if you are trying to remove cooking odors, moisture, heat, etc., generated from cooking, then, no, recirculating fans only "recirculate" back into the space. Some of the odors will be removed by the charcoal filter as long as it is replaced with great frequency. The moisture and heat are going nowhere expect back into your face. What grease is not caught in the grease traps will also be recirculated into your face.

When ever is is possible (easily done) I recommend to all my clients to vent the hood outdoors. I personaly don't smelling steak or fish for the next day or so. If it can go stright up thru the roof or if the stove backs to an exterior wall I suggest the vent to the exterior.

Most island down draft come on automatically. Most work quite well.

As to the remark that the hoods are there to keep the cabinets above from catching on fire???? There would be no cabinets above if there was no hood. Jerry is right about that thin piece of metal not keeping the house from burning down.

Recirculating hoods are allowed by the code. What is strange about the code is the that the code states that range hoods shall discharge to the outdoors.

Then it (the code) comes along with an exception and says; where installed in accordance with the manufacturer’s installation instructions, and where mechanical or natural ventilation is otherwise provided, ((((what is this saying?? Do you have to provide additional ventilation IF you use a ductless vent hood??? Different thread!!!))))) listed and labeled ductless range hoods shall not be required to discharge to

the outdoors. Crazy huh?

Also on the statement about the hood being there to "protect" the cabinets. That is a true statement even though it is also there to take away odors and grease.

M1505.1 General. Domestic open-top broiler units shall be provided with a metal exhaust hood, not less than 28 gage, with 1/4 inch (6 mm) between the hood and the underside of combustible material or cabinets.A clearance of at least 24 inches (610 mm) shall be maintained between the cooking surface and the
combustible material or cabinet. The hood shall be at least as wide as the broiler unit and shall extend over the entire unit. Such exhaust hood shall discharge to the outdoors and shall be equipped with a backdraft damper or other means to control
infiltration/exfiltration when not in operation. Broiler units incorporating an integral exhaust system, and listed and labeled for use without an exhaust hood, need not be provided with an exhaust hood.

So it actually does protect the cabinets from heat.

Originally Posted by Jerry Peck

"Commercial" ranges do, and the hood also requires an extinguishing system, grease filters, and other things.

Not all commercial hoods require extinguishing systems and grease filters. There are two types of commercial hoods; Type I and Type II. Type I requires fire suppression where Type II is for odor vapors. Underlined is from the code.

Type I hoods shall be installed where cooking appliances produce grease or smoke, such as occurs with griddles, fryers, broilers, ovens, ranges and wok ranges.

Type II hoods shall be installed here cooking or dishwashing appliances produce heat, steam, or products of combustion and do not produce grease or smoke, such as steamers, kettles, pasta cookers and dishwashing machines.

And of course a few exceptions.

Originally Posted by Jerry Peck

"Commercial" ranges *are not allowed* to be used in dwelling units.

Jerry where do you find where a commercial hood is not allowed in dwelling units?

Originally Posted by Wayne Carlisle

Recirculating hoods are allowed by the code. What is strange about the code is the that the code states that range hoods shall discharge to the outdoors.

Wayne,

Too many things to comment on now as I have to run out, but here is one addressing what you stated above, showing that what you stated is incorrect.
From the 2006 IRC. (underlining is mine)

- M1503.1 General.

Range hoods shall discharge to the outdoors through a single-wall duct. The duct serving the hood shall have a smooth interior surface, shall be air tight and shall be equipped with a backdraft damper. Ducts serving range hoods shall not terminate in an attic or crawl space or areas inside the building.

- - Exception:

Where installed in accordance with the manufacturer’s installation instructions, and where mechanical or natural ventilation is otherwise provided, listed and labeled ductless range hoods shall not be required to discharge to the outdoors.

How am I incorrect? I said the same thing you did.

Maybe in your hurry to run to the local coff shop to swap lies you didn't get to read the whole thing and just glanced at it!

Originally Posted by Wayne Carlisle

How am I incorrect? I said the same thing you did.

Maybe in your hurry to run to the local coff shop to swap lies you didn't get to read the whole thing and just glanced at it!

Dang...

Best

Ron

Originally Posted by Jerry Peck

- M1503.1 General.

Range hoods shall discharge to the outdoors through a single-wall duct. The duct serving the hood shall have a smooth interior surface, shall be air tight and shall be equipped with a backdraft damper. Ducts serving range hoods shall not terminate in an attic or crawl space or areas inside the building.

- - Exception:

Where installed in accordance with the manufacturer’s installation instructions, and where mechanical or natural ventilation is otherwise provided, listed and labeled ductless range hoods shall not be required to discharge to the outdoors.

So I'm probably going to set mine up as recirculating into the kitchen...but if you go ductless and you are not required to discharge outdoors, why can't you discharge to anywhere in the building? (i.e. garage)

Originally Posted by Chris Regacho

So I'm probably going to set mine up as recirculating into the kitchen...but if you go ductless and you are not required to discharge outdoors, why can't you discharge to anywhere in the building? (i.e. garage)

Then you would break the seperation wall and why else would you want to discharge it anywhere else in the home but the kitchen

Originally Posted by Ted Menelly

Then you would break the seperation wall and why else would you want to discharge it anywhere else in the home but the kitchen

We'll I considered discharging it into the garage. The kitchen wall backs up to the garage but based on how the garage is positioned I can't easily vent outside. (2 sides visible from front of home so I don't want to vent to those sides and the other side would be too long of a run and would have to go through the laundry room)

Originally Posted by Wayne Carlisle

How am I incorrect? I said the same thing you did.

Maybe in your hurry to run to the local coff shop to swap lies you didn't get to read the whole thing and just glanced at it!

You, sir, are correct.

I missed this part:

Originally Posted by Wayne Carlisle

IF you use a ductless vent hood??? Different thread!!!))))) listed and labeled ductless range hoods shall not be required to discharge to the outdoors.

Now, ... for the rest of the story ...

Originally Posted by Wayne Carlisle

Also on the statement about the hood being there to "protect" the cabinets. That is a true statement even though it is also there to take away odors and grease.

M1505.1 General. Domestic open-top broiler units shall be provided with a metal exhaust hood, not less than 28 gage, with 1/4 inch (6 mm) between the hood and the underside of combustible material or cabinets.A clearance of at least 24 inches (610 mm) shall be maintained between the cooking surface and the
combustible material or cabinet. The hood shall be at least as wide as the broiler unit and shall extend over the entire unit. Such exhaust hood shall discharge to the outdoors and shall be equipped with a backdraft damper or other means to control
infiltration/exfiltration when not in operation. Broiler units incorporating an integral exhaust system, and listed and labeled for use without an exhaust hood, need not be provided with an exhaust hood.

So it actually does protect the cabinets from heat.

Only when there the hood has that 1/4" clearance, and (as I recall) I have not seen a residential hood which provides that 1/4" clearance when installed.

Thus none of them provide any protection - the heat simply heats the metal which then heats the combustible cabinets which then catch fire.

Jerry where do you find where a commercial hood is not allowed in dwelling units?

From the code.












Oh, you want a reference?
From the 2006 IRC. (underlining is mine)

- G2447.2 (623.2) Prohibited location.

Cooking appliances designed, tested, listed and labeled for use in commercial occupancies shall not be installed within dwelling units or within any area where domestic cooking operations occur.

That's why, when the first "Commercial" labeled appliances started appearing in high end residences they were rejected and had to be removed ... or beg the AHJ to give that letter called "Special Permission".

Did not take long before the manufacturers of those no longer put "Commercial" on them, but instead were labeled with "Professional", and their listing and labeling provided for their use in residences.

That's in the gas code. This code is refering to stoves and other gas appliances. This section doesn't say anything about commercial exhaust hoods not being allowed. A commercial exhaust hood is not a cooking appliance.

Originally Posted by Wayne Carlisle

That's in the gas code. This code is refering to stoves and other gas appliances. This section doesn't say anything about commercial exhaust hoods not being allowed. A commercial exhaust hood is not a cooking appliance.

"This section doesn't say anything about commercial exhaust hoods not being allowed. A commercial exhaust hood is not a cooking appliance."

Correct, and we weren't talking about "commercial exhaust hoods", we were talking about "commercial cooking appliances", unless I missed something someplace.

Not sure what your beef is???

What's my beef???? Uhhhhhhh after reading back through I somehow switched from a commercial gas stove to a commercial vent hood. When I asked about where it was that the commercial vent hood wasn't allowed then you posted about gas appliances not being allowed so I stuck my head plumb up my behind and forgot to pull it out! Oooops sorry! My bad!

Wayne,

Not to worry, I went back and read what you posted again and, sure enough, you said "hood", however, I had stated "appliance" so that is what I read in your response ... oops on my part too ... just another example of us not fully reading what someone has written, and it so often leads to miscommunication and wrong answers (the answers are 'right answers', only they are 'right' to a 'different question' ).

Hi all, this is my first post but I did use the search function and didn't want to start another thread and have someone think I didn't dig around. I am getting to the point of putting in my new house for the insulation and drywall. I am doing the spray in foam insulation and drywall on top of it. I am using a gas cooktop range which is on the same wall of the inside garage wall. If I cut a hole to vent outside it would put me directly in the garage. If I vented from there, it would make a 90 degree and head to the front of the garage and then vent outside. This would make the run approx. 10ft to get to the outside with a 90 on the hood. My other option is to go straight up and out the roof, or I would have to drill a 6" hole through approx. 10 ibeams to get to the outside of the house. What is my best option on this? I am really scratching my head here.

Oh, and any wall I go through is a ICF wall with 6" of concrete which can be done with a large core drill bit, except for the roofline.

Originally Posted by Stephen Byington

I am using a gas cooktop range which is on the same wall of the inside garage wall. If I cut a hole to vent outside it would put me directly in the garage. If I vented from there, it would make a 90 degree and head to the front of the garage and then vent outside. This would make the run approx. 10ft to get to the outside with a 90 on the hood.

I'd go through the garage wall, along it, then outside.

And, besides using 26 gage minimum for the exhaust duct, I would also box the duct in and wrap with drywall (the three exposed sides of the box) and the end of the box, all the way to the exterior wall. That would meet and exceed code requirements for garage/living space separation.

Thank you very much, that is the easiest for me. Great site, I am sure I will be surfing through the info quite a bit now.