# Range Hood for Gas Cooktop doesn't require Venting?!?



## Chuck_M (Feb 11, 2022)

Hello Everyone,

Hope you guys can help me out on the building code.
I'm having a house built by a production builder and I asked why my Gas Cooktop has a recirculating range and not a vented one. Their answer was it isn't required in South Carolina. I've asked to pay for it to be vented and they refused. They've told me if you can show it is violating the code they will do it as right now the production builder sub contracts the HVAC and Kitchen Appliances to one supplier. So they just don't wait to pay for it if it's required.

I've been doing some digging for about two weeks and even reached out to the City's inspectors. They pointed me to the IRC 2015

*Section M1503 Range Hoods

M1503.1 General*

Range hoods shall discharge to the outdoors through a duct. The duct serving the hood shall have a smooth interior surface, shall be air tight, shall be equipped with a back-draft damper and shall be independent of all other exhaust systems. 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 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.


They are considering a recirculating fan a mechanical ventilation... It's pushing the air back in the room... I find it kind of pointless, the carbon filters will catch some of the grease and bad smell but the Carbon Monoxide, Formaldehyde, and Moisture will just be recirculating in the room.



======> *Question 1*. Is a recirculating vent acceptable?



*M1507.4 Local Exhaust Rates*

_Local exhaust_ systems shall be designed to have the capacity to exhaust the minimum air flow rate determined in accordance with Table M1507.4.

TABLE M1507.4
MINIMUM REQUIRED LOCAL EXHAUST RATES FOR ONE- AND TWO-FAMILY DWELLINGS

*AREA TO BE
EXHAUSTED**EXHAUST RATES*Kitchens100 cfm intermittent or 25 cfm continuousBathrooms-Toilet
RoomsMechanical exhaust capacity of 50 cfm
intermittent or 20 cfm continuous
For SI: 1 cubic foot per minute = 0.0004719 m3/s.


======>  *Question 2.* Does this mean it has to be exhausted to the outside?



Thank you in advance


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## mtlogcabin (Feb 11, 2022)

Your answer is in Table M1507.4 for the kitchen exhaust requirement. Typically this is accomplished with a kitchen hood exhaust to the outside


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## Chuck_M (Feb 11, 2022)

mtlogcabin said:


> Your answer is in Table M1507.4 for the kitchen exhaust requirement. Typically this is accomplished with a kitchen hood exhaust to the outside



Thank you!

Would a recirculating vent be acceptable as a Local Exhaust?

Also any other codes that they are in violation of if they put a recirculating vent?


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## Chuck_M (Feb 11, 2022)

Wait a second. On top of the two questions above.

*Section M1503 Range Hoods

M1503.1 General*

Range hoods shall discharge to the outdoors through a duct. The duct serving the hood shall have a smooth interior surface, shall be air tight, shall be equipped with a back-draft damper and shall be independent of all other exhaust systems. 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 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.


============>  M1507.4 is only for Mechanical Ventilation. So I don't know if the Kitchen item would apply. Would it?


*Section M1507 Mechanical Ventilation

M1507.1 General*

Where local exhaust or whole-house mechanical ventilation is provided, the equipment shall be designed in accordance with this section.


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## Sifu (Feb 11, 2022)

No access to the SC codes but there is no requirement for domestic cooking exhaust in the IRC except for open top broilers.  Where it is provided it must be in accordance with 1503.3, which allows it to be ductless, which is recirculating.  Apparently there is also not a requirement for them to satisfy a customer who is willing to pay for it.


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## Chuck_M (Feb 11, 2022)

Sifu said:


> No access to the SC codes but there is no requirement for domestic cooking exhaust in the IRC except for open top broilers.  Where it is provided it must be in accordance with 1503.3, which allows it to be ductless, which is recirculating.  Apparently there is also not a requirement for them to satisfy a customer who is willing to pay for it.


What about

*M1507.4 Local Exhaust Rates*

_Local exhaust_ systems shall be designed to have the capacity to exhaust the minimum air flow rate determined in accordance with Table M1507.4.

TABLE M1507.4
MINIMUM REQUIRED LOCAL EXHAUST RATES FOR ONE- AND TWO-FAMILY DWELLINGS

*AREA TO BE
EXHAUSTED**EXHAUST RATES*Kitchens100 cfm intermittent or 25 cfm continuousBathrooms-Toilet
RoomsMechanical exhaust capacity of 50 cfm
intermittent or 20 cfm continuous
For SI: 1 cubic foot per minute = 0.0004719 m3/s.


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## Sifu (Feb 11, 2022)

That is not a hood over a cooking appliance.  That is an exhaust fan used in a local exhaust system.  I imagine your house is not using a local exhaust system, rather it is using a whole house system.  Either way, even if you are using a local exhaust system that is typically an exhaust fan in the ceiling somewhere in the kitchen, and at those minimum rates would have little effect on cooking.  Typical range hoods are 200cfm intermittent to well in excess of 600cfm.  The local exhaust you are referencing is not meant for cooking.


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## Chuck_M (Feb 11, 2022)

Thank you!

I'm trying to figure out a way to force them to put the range vent to exhaust outside. I'm shocked that it is legal to have an indoor fire without requiring external venting...


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## Chuck_M (Feb 11, 2022)

What about ASHRAE 62.2 ventilation requirements?
I see this a silver bullet. No?



			https://www.ashrae.org/File%20Library/Technical%20Resources/Standards%20and%20Guidelines/Standards%20Addenda/62_2_2013_c_20151208.pdf
		




			https://www.energy.gov/sites/default/files/2014/12/f19/ba_innovations_2014_ASHRAE%2062_2.pdf
		







						Indoor Air Quality Understanding ASHRAE 62 2 | Springtime Builders
					

A blog focusing on building and construction in the Asheville area including information on energy efficiency, indoor air quality and passive solar design.




					www.springtimebuilders.com


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## Chuck_M (Feb 11, 2022)

ANSI/ASHRAE Standard 62.2-2019  Ventilation and Acceptable Indoor Air Quality in Residential Buildings






						Read-Only Versions of ASHRAE Standards
					

Learn more about Read-Only Versions of ASHRAE Standards at ashrae.org




					www.ashrae.org


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## Sifu (Feb 11, 2022)

*Forcing* isn't a good strategy.  I would have concerns that they don't want to given that you wish to pay them.  How confident in the *FORCED* work would you be anyway.  If you are set on getting it then hire your own contractor and do it separately.  Codes don't require the exhaust since the appliances are typically used sporadically and under constant supervision, unlike a furnace or water heater that needs dedicated venting.  Compliance with ASHRAE isn't required in most places.  Unless there is an amendment requiring it in your state code or local adoption then there is no requirement.


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## ICE (Feb 11, 2022)

Recirculating residential range hoods are not permitted in California.  Residential range hoods are not required in California.  In my case the hood exhausts to the exterior and my wife opens a window or two whenever she is cooking on the stove. Her olfactory sensitivity is amazing. 

I am with sifu on this.  You should hire a contractor to install a vented hood.  The builder might object but having no hood is not healthy.


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## Chuck_M (Feb 12, 2022)

Sifu said:


> *Forcing* isn't a good strategy.  I would have concerns that they don't want to given that you wish to pay them.  How confident in the *FORCED* work would you be anyway.  If you are set on getting it then hire your own contractor and do it separately.  Codes don't require the exhaust since the appliances are typically used sporadically and under constant supervision, unlike a furnace or water heater that needs dedicated venting.  Compliance with ASHRAE isn't required in most places.  Unless there is an amendment requiring it in your state code or local adoption then there is no requirement.



I got a quote for doing it now pre-drywall would be 600$.
Doing it AFTER would be 4000$.


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## Joe.B (Feb 14, 2022)

ICE said:


> Recirculating residential range hoods are not permitted in California.


Do you have a reference for this, I have heard this before and I couldn't find it. I think this _should_ be true and I would love to have some "ammo" to back this up. Thanks!


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## ICE (Feb 14, 2022)

Joe.B said:


> Do you have a reference for this, I have heard this before and I couldn't find it. I think this _should_ be true and I would love to have some "ammo" to back this up. Thanks!


I looked for it too but couldn't find it.  I did not look at the Energy Code.


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## Chuck_M (Feb 14, 2022)

https://www.energy.gov/sites/default/files/2014/12/f19/ba_innovations_2014_ASHRAE%2062_2.pdf
		

and





						Pollutant Exposures from Natural Gas Cooking Burners: A Simulation-Based Assessment for Southern California (Technical Report) | OSTI.GOV
					

The U.S. Department of Energy's Office of Scientific and Technical Information




					www.osti.gov


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## Mr209Smith (Feb 14, 2022)

Had this issue come up not too long ago. This is what I found. We made them go directly to the outside.

*2019 Building Energy Efficiency Standards Residential Compliance Manual 4.6.7 Local Exhaust*

_Local exhaust (sometimes called spot ventilation) has long been required for bathrooms and kitchens to remove moisture and odors at the source. Building codes have required an operable window or an exhaust fan in bathrooms for many years and have generally required kitchen exhaust either directly through a fan or indirectly through a recirculating range hood and an operable window. The Energy Standards recognize the limitations of these indirect methods of reducing moisture and odors and requires that these spaces be mechanically exhausted directly to outdoors, even if windows are present. Moisture condensation on indoor surfaces are a leading cause of mold and mildew in buildings. The occurrence of asthma is also associated with high interior relative humidity. Therefore, it is important to exhaust the excess moisture from bathing and cooking directly at the source._


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## Chuck_M (Feb 14, 2022)

Mr209Smith said:


> Had this issue come up not too long ago. This is what I found. We made them go directly to the outside.
> 
> *2019 Building Energy Efficiency Standards Residential Compliance Manual 4.6.7 Local Exhaust*
> 
> _Local exhaust (sometimes called spot ventilation) has long been required for bathrooms and kitchens to remove moisture and odors at the source. Building codes have required an operable window or an exhaust fan in bathrooms for many years and have generally required kitchen exhaust either directly through a fan or indirectly through a recirculating range hood and an operable window. The Energy Standards recognize the limitations of these indirect methods of reducing moisture and odors and requires that these spaces be mechanically exhausted directly to outdoors, even if windows are present. Moisture condensation on indoor surfaces are a leading cause of mold and mildew in buildings. The occurrence of asthma is also associated with high interior relative humidity. Therefore, it is important to exhaust the excess moisture from bathing and cooking directly at the source._


Can you send me a link to this.


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## Chuck_M (Feb 14, 2022)

Found it
nvm


			https://energycodeace.com/site/custom/public/reference-ace-2019/index.html#!Documents/46indoorairqualityandmechanicalventilation.htm


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## Joe.B (Feb 14, 2022)

I'll be one of the first people to say that indoor ranges *should *be vented directly outside, and I've heard many people say something to the effect of "Recirculating residential range hoods are not permitted in California." As of yet I have not found anything in the 2019 Ca Building Standards Code to back this up. The document you reference is a compliance manual, not the code. I feel citing this as a way to "make them go directly outside" is thin at best.


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## Chuck_M (Feb 14, 2022)

https://energycodeace.com/site/custom/public/reference-ace-2019/index.html#!Documents/46indoorairqualityandmechanicalventilation.htm
		


*B. Ventilation Rate for Demand-Controlled Local Exhaust*

A minimum exhaust airflow of 100 CFM is required for vented kitchen range hoods, and 300 CFM or 5 ACH is required for other kitchen exhaust fans. A minimum exhaust airflow of 50 CFM is required for bathroom fans.

The 100 CFM requirement for the range hood or microwave/hood combination is the minimum to adequately capture the moisture, particulates, and other products of cooking and/or combustion. Only in kitchens that are enclosed, the exhaust requirement can also be met with either a ceiling or wall-mounted exhaust fan or with a ducted fan or ducted ventilation system that can provide at least five air changes of the kitchen volume per hour. Recirculating range hoods that do not exhaust pollutants to the outside cannot be used to meet the requirements of ASHRAE Standard 62.2 unless paired with an exhaust system that can provide at least five air changes of the kitchen volume per hour.

The 2019 Title 24 Part 6 standards require verification that range hoods are HVI-certified to provide at least one speed setting at which they can deliver at least 100 CFM at a noise level of 3 sones or less. Verification must be in accordance with the procedures in _Reference Residential Appendix_ RA3.7.4.3. Range hoods that have a minimum airflow setting exceeding 400 CFM are exempt from the noise requirement. HVI listings are available at:

https://www.hvi.org/proddirectory/CPD_Reports/section_1/index.cfm

ASHRAE Standard 62.2 limits exhaust airflow when atmospherically vented combustion appliances are located inside the pressure boundary. This is particularly important to observe when large range hoods are installed. Refer to Section 4.6.8.4 below for more information.


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## Mr209Smith (Feb 14, 2022)

See the California Energy Commission Blueprint 131. 





						Blueprint Newsletter, July-Sept 2020, Issue 131
					

Nonresidential Mechanical Acceptance Testing New 2019 Energy Code Resources Available on the ORC 2019 HERS Reference Card 2019 ATTCP Reference Card 2019 Water Heater Guides 2019 Energy Code Envelope Air Sealing Fact Sheet 2019 Energy Code Presentations




					www.energy.ca.gov
				




Does a recirculating range hood with no exhaust to the outdoors meet the mandatory requirements?
_No. When a recirculating range hood without outdoor exhaust is installed, another system must also be installed that exhausts to the outdoors and meets the local kitchen exhaust flow rate and sound requirements in ASHRAE 62.2._

While it isn't code, it certainly speaks to the intent of the code.


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## Chuck_M (Feb 14, 2022)

So _ASHRAE 62.2 is not a code but a recommendation to the code?_


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## ICE (Feb 14, 2022)

Banning recirculating range hoods came up in a class several years ago so I am convinced that there is a code to back that up.  I didn’t encounter many of them.  The fans are more of a decoration than a functioning appliance.


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## Chuck_M (Feb 15, 2022)

Chuck_M said:


> So _ASHRAE 62.2 is not a code but a recommendation to the code?_


Is it a code?


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## Ed Cooke (Feb 15, 2022)

Chuck_M said:


> Hello Everyone,
> 
> Hope you guys can help me out on the building code.
> I'm having a house built by a production builder and I asked why my Gas Cooktop has a recirculating range and not a vented one. Their answer was it isn't required in South Carolina. I've asked to pay for it to be vented and they refused. They've told me if you can show it is violating the code they will do it as right now the production builder sub contracts the HVAC and Kitchen Appliances to one supplier. So they just don't wait to pay for it if it's required.
> ...


I do not wish to taint your thoughts or opinion. I am in Ca. which is not where you are, so my words are only to meet a point. The contractor is correct that an exterior exhausted hood is not required, but they must meet all of the other ventilation requirements, ASHRAE, for your specific jurisdiction. If you speak to the code authority, make it a Plan Reviewer or Building Official. 
As a personal thought, outside is the best way to remove cooking odors, you are on the right track!!


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## Chuck_M (Feb 15, 2022)

Ed Cooke said:


> I do not wish to taint your thoughts or opinion. I am in Ca. which is not where you are, so my words are only to meet a point. The contractor is correct that an exterior exhausted hood is not required, but they must meet all of the other ventilation requirements, ASHRAE, for your specific jurisdiction. If you speak to the code authority, make it a Plan Reviewer or Building Official.
> As a personal thought, outside is the best way to remove cooking odors, you are on the right track!!


Thank you Ed!
I agree with you, there is no situation where an indoor gas flame is healthy in the long term. Specially if you have children kids in the house.


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## Sifu (Feb 15, 2022)

Dare I say millions have been installed without a hood, as have non-vented gas decorative appliances.  You are presenting what may be a best practice and a preference.  That said, if there is a code, amendment or standard that has been legally adopted that requires hoods then it should be administered for everybody governed by that adoption.


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## Chuck_M (Feb 15, 2022)

Sifu said:


> Dare I say millions have been installed without a hood, as have non-vented gas decorative appliances.  You are presenting what may be a best practice and a preference.  That said, if there is a code, amendment or standard that has been legally adopted that requires hoods then it should be administered for everybody governed by that adoption.


You know that there are still people that smoke. Doesn't mean it is healthly.
Also did you know there are houses that still have Asbestos! Doesn't mean it's healthy.

I dont want to debate this. It comes down to simple math for me.
Is the chances of getting carbon monoxide poisoning lower when there exhaust is to the outside? Yes. Forget about humidity and all the other issues that are also avoided when the exhaust is vented out.
On a new build, I understand pre production homes want to save every penny but saving on health of the home owner is a very low bar.


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## ICE (Feb 15, 2022)

Chuck_M said:


> I dont want to debate this.


Oh but you do.


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## ICE (Feb 15, 2022)

Ed Cooke said:


> I do not wish to taint your thoughts or opinion.


Oh but you have.


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## mtlogcabin (Feb 15, 2022)

Chuck_M said:


> *Exception*: Where installed in accordance with the manufacturer's instructions, and where mechanical or natural _*ventilation*_* i*s otherwise provided, _listed_ and _labeled_ ductless range hoods shall not be required to discharge to the outdoors.



[RB] VENTILATION. The natural or mechanical process of supplying conditioned or unconditioned air to, or removing such air from, any space.

A recirculating fan does not meet the definition of mechanical ventilation. A window in the kitchen that can be opened meets the definition of natural ventilation. Do you have a kitchen window that can be opened? If yes then the recirculating hood meets code


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## mark handler (Feb 16, 2022)

ICE said:


> Recirculating residential range hoods are not permitted in California.  Residential range hoods are not required in California.  In my case the hood exhausts to the exterior and my wife opens a window or two whenever she is cooking on the stove. Her olfactory sensitivity is amazing.
> 
> I am with sifu on this.  You should hire a contractor to install a vented hood.  The builder might object but having no hood is not healthy.


*ICE where does that come from? "Residential range hoods are not required in California."*


California Mechanical Code, Section 402.1.2 says that ventilation requirements for single-family dwellings shall be in accordance with Chapter 4 of the California Mechanical Code or ASHRAE 62.2. “ASHRAE” stands for American Society of Heating, Refrigerating and Air-Conditioning Engineers.

ASHRAE 62.2 is a standard that was developed to regulate ventilation requirements for residential buildings that are 3 stories or less, so it is applicable to one- and two-family dwellings but not to apartment complexes. *It states that kitchen areas must contain mechanical ventilation to meet residential ventilation requirements*.



			https://energycodeace.com/site/custom/public/reference-ace-2019/index.html#!Documents/46indoorairqualityandmechanicalventilation.htm
		

2019 Building Energy Efficiency Standards
*4.6 Indoor Air Quality and Mechanical Ventilation*
"...Opening and closing windows and continuous operation of central fan-integrated ventilation systems are not allowable options for meeting dwelling unit ventilation requirements. The requirements of ASHRAE Standard 62.2 focus on providing continuous dwelling unit mechanical ventilation, as well as local exhaust ventilation at known sources of pollutants or moisture, such as kitchens, bathrooms, and laundries.
Limiting the sources of indoor pollutants is one important method for protecting indoor air quality. *Kitchen ranges used for preparation of food have been identified as a source of indoor air pollution that must be addressed, *and builders should adhere to the requirements of Section 4.504 of the California Green Building Standards Code for the selection of materials and finishes that have no or low emissions of air pollutants such as formaldehyde and volatile organic compounds (VOCs). The California Air Resources Board (CARB) also provides guidance for reducing indoor air pollution in homes..."


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## mark handler (Feb 16, 2022)

2018 South Carolina Mechanical Code
505.3 Exhaust Ducts
Domestic cooking exhaust equipment shall discharge to the outdoors through sheet metal ducts constructed of galvanized steel, stainless steel, aluminum or copper. Such ducts shall have smooth inner walls, shall be air tight, shall be equipped with a backdraft damper, and shall be independent of all other exhaust systems. Installations in Group I-1 and I-2 occupancies shall be in accordance with the South Carolina Building Code and Section 904.13 of the South Carolina Fire Code.

Exceptions:
In other than Groups I-1 and I-2, where installed in accordance with the manufacturer's instructions and where mechanical or natural ventilation is otherwise provided in accordance with Chapter 4, listed and labeled ductless range hoods shall not be required to discharge to the outdoors.
Ducts for domestic kitchen cooking appliances equipped with downdraft exhaust systems shall be permitted to be constructed of Schedule 40 PVC pipe and fittings provided that the installation complies with all of the following:
2.1. The duct shall be installed under a concrete slab poured on grade.
2.2. The underfloor trench in which the duct is installed shall be completely backfilled with sand or gravel.
2.3. The PVC duct shall extend not more than 1 inch (25 mm) above the indoor concrete floor surface.
2.4. The PVC duct shall extend not more than 1 inch (25 mm) above grade outside of the building.
2.5. The PVC ducts shall be solvent cemented


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## ICE (Feb 16, 2022)

mark handler said:


> *ICE where does that come from? "Residential range hoods are not required in California."*


Mechanical ventilation for a kitchen is required but it does not have to be a range hood.

Note the cliff that California jumped off:
_Kitchen range hood fans are now required to be verified by a HERS Rater. The new verification protocol requires comparing the installed model to ratings in the Home Ventilating Institute (HVI) directory of certified ventilation products to confirm the installed range hood is rated to meet the required airflow and sound requirements specified in ASHRAE 62.2. See section 4.6.7 below for more detail. Kitchen range hood fans that exhaust more than 400 CFM at minimum speed are exempt from this requirement._

A HERS Rater for a range hood?????  When they finally run out of goofy ideas a day will come when a pile of ashes from a pile of burnt money will be required.


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## Chuck_M (Feb 16, 2022)

mtlogcabin said:


> [RB] VENTILATION. The natural or mechanical process of supplying conditioned or unconditioned air to, or removing such air from, any space.
> 
> A recirculating fan does not meet the definition of mechanical ventilation. A window in the kitchen that can be opened meets the definition of natural ventilation. Do you have a kitchen window that can be opened? If yes then the recirculating hood meets code


Well it is not a prison, so there are windows...lol
It is an open concept, there is only 2 window in the front ( living room ) but non in the back (garage) and none on the side since it is a middle unit. Is there any requirements on where the locations are? Distance and size?



mark handler said:


> 2018 South Carolina Mechanical Code
> 505.3 Exhaust Ducts
> Domestic cooking exhaust equipment shall discharge to the outdoors through sheet metal ducts constructed of galvanized steel, stainless steel, aluminum or copper. Such ducts shall have smooth inner walls, shall be air tight, shall be equipped with a backdraft damper, and shall be independent of all other exhaust systems. Installations in Group I-1 and I-2 occupancies shall be in accordance with the South Carolina Building Code and Section 904.13 of the South Carolina Fire Code.
> 
> ...


This is where the builder says, we are building in accordance to the manufacturer's instructions.


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## klarenbeek (Feb 16, 2022)

Just throwing this out there, but this is a good example of where codes are the minimum standard, not necessarily best practice.  In the ICC world at least, hoods are not required above ranges of any kind other than open top broilers within a dwelling unit.  Not required in the IRC, and IMC 505.6 Spells out that they are only required in other than group R occupancies.  Listed recirculating hoods are allowed in all cases.


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## Genduct (Feb 16, 2022)

Chuck_M said:


> You know that there are still people that smoke. Doesn't mean it is healthly.
> Also did you know there are houses that still have Asbestos! Doesn't mean it's healthy.
> 
> I dont want to debate this. It comes down to simple math for me.
> ...


Chuck,  it is clear that you have your heart set on a (California) hood exhaust that removes the cooking orders to the outside.

Your Code quote said: "Where installed in accordance with the manufacturer's 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."

It CLEARLY Says Listed and Labeled AND Natural Ventilation is provided!
Well Natural Air Changes is the reality of all structures and when the blower door test shows less than 1/3 ACH then you have a make up fan to positively provide the Outside Air to dilute the Problem you mention.

Your Code recitation shows your Contractor is correct for your State, according to the Code you posted.

So, ask him how much to get it done the way you PREFER is my suggestion.  The Code supports his POV

IMHO,  Mike B


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## Chuck_M (Feb 16, 2022)

What is considered natural ventilation? Anywhere in the code that has clarity ?


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## Genduct (Feb 16, 2022)

Chuck_M said:


> What is considered natural ventilation? Anywhere in the code that has clarity ?


Nat Ventilation is the Infiltration that happens when the wind blows or the temp diff that creates the stack effect.
The inside air goes out and is replaced through cracks in the windows and doors or even the building itself.

many people don't realize that a "TIGHT" house has 1/3 of the air in your home exchanged with the outside EVERY HOUR.   That is a Tight House.  Older homes can be from a little less to more than the entire volumn of your home exchanged with outside EVERY HOUR

You're not living in a submarine, a sealed bottle


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## Chuck_M (Feb 17, 2022)

Genduct said:


> Nat Ventilation is the Infiltration that happens when the wind blows or the temp diff that creates the stack effect.
> The inside air goes out and is replaced through cracks in the windows and doors or even the building itself.
> 
> many people don't realize that a "TIGHT" house has 1/3 of the air in your home exchanged with the outside EVERY HOUR.   That is a Tight House.  Older homes can be from a little less to more than the entire volumn of your home exchanged with outside EVERY HOUR
> ...



Not exactly. The builder does a blow door test after drywall and he told me on the last phase of the identical town homes the middle townhouses got between 0.8-1.75ACH. The outer units are much worse between 2 - 4ACH.

I've also had an inspector there twice and was very picky on the fireblock everywhere and there isn't a vent for the cooktop  So I won't be surprised if I get 0.8 ACH or better. Which is pretty tight.


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## Beniah Naylor (Feb 17, 2022)

This is outside of the range of my experience, and you may already know more about this than I do.

Your house is very tight. If you want a range hood, you will have to find a way to bring more air into the house to compensate for what is exhausted from the house. If you have to bring in air from outside, it kind of defeats the purpose of having your house that tight. There are recirculating systems out there for that purpose, but I don't have any experience with them. 

Me personally, if I were building a house that was that tight, I would hire a mechanical engineer to spec out a balanced system for the whole house. I am not usually the kind of person who would call in an engineer, but this area is over my head.


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## Chuck_M (Feb 17, 2022)

They need to have a score below 5ACH to pass final inspections.


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## mark handler (Feb 17, 2022)

ICE said:


> Mechanical ventilation for a kitchen is required but it does not have to be a range hood.
> 
> Note the cliff that California jumped off:
> _Kitchen range hood fans are now required to be verified by a HERS Rater. The new verification protocol requires comparing the installed model to ratings in the Home Ventilating Institute (HVI) directory of certified ventilation products to confirm the installed range hood is rated to meet the required airflow and sound requirements specified in ASHRAE 62.2. See section 4.6.7 below for more detail. Kitchen range hood fans that exhaust more than 400 CFM at minimum speed are exempt from this requirement._
> ...


Yes, in the 2019 CA Energy code, they are required to have a HERS Rater for a range hood.


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## mark handler (Feb 17, 2022)

Chuck_M said:


> Well it is not a prison, so there are windows...lol
> It is an open concept, there is only 2 window in the front ( living room ) but non in the back (garage) and none on the side since it is a middle unit. Is there any requirements on where the locations are? Distance and size?
> 
> 
> This is where the builder says, we are building in accordance to the manufacturer's instructions.


You are required to comply with *both* the state code and the manufacturer's instructions.
The manufacturer's instructions, may say not required but the State says it is, therefore it is required.


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## Chuck_M (Feb 17, 2022)

What about this section of the code?


*Section G2407 (304) Combustion, Ventilation and Dilution Air

G2407.1 (304.1) General*

Air for combustion, ventilation and dilution of flue gases for appliances installed in buildings shall be provided by application of one of the methods prescribed in Sections G2407.5 through G2407.9. Where the requirements of Section G2407.5 are not met, outdoor air shall be introduced in accordance with one of the methods prescribed in Sections G2407.6 through G2407.9. Direct-vent appliances, gas appliances of other than natural draft design, vented gas appliances not designated as Category I and appliances equipped with power burners, shall be provided with combustion, ventilation and dilution air in accordance with the appliance manufacturer's instructions.

*Exception: *Type 1 clothes dryers that are provided with makeup air in accordance with Section G2439.5.


*G2407.12 (304.12) Protection From Fumes and Gases*

Where corrosive or flammable process fumes or gases, other than products of combustion, are present, means for the disposal of such fumes or gases shall be provided. Such fumes or gases include carbon monoxide, hydrogen sulfide, ammonia, chlorine and halogenated hydrocarbons.

In barbershops, beauty shops and other facilities where chemicals that generate corrosive or flammable products, such as aerosol sprays, are routinely used, nondirect vent-type appliances shall be located in a mechanical room separated or partitioned off from other areas with provisions for combustion air and dilution air from the outdoors. Direct-vent appliances shall be installed in accordance with the appliance manufacturer's instructions


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## Genduct (Feb 17, 2022)

Chuck_M said:


> Not exactly. The builder does a blow door test after drywall and he told me on the last phase of the identical town homes the middle townhouses got between 0.8-1.75ACH. The outer units are much worse between 2 - 4ACH.
> 
> I've also had an inspector there twice and was very picky on the fireblock everywhere and there isn't a vent for the cooktop  So I won't be surprised if I get 0.8 ACH or better. Which is pretty tight.


Chuck, You are correct about the test.   I was going to the next step after the Blower door test to the assumptions made to translate the Test value into Natural Air Changes.  Of course the actuals are going to be affected by wind and temperature so the Actual / natural value will always change with conditions

I didn't mean to confuse the conversation


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## steveray (Feb 18, 2022)

And then the kitchen exhaust needs make up air too....


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## Chuck_M (Feb 18, 2022)

steveray said:


> And then the kitchen exhaust needs make up air too....



Where in the code does it state it needs make up air?


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## steveray (Feb 18, 2022)

M1503.4 Makeup air required. Exhaust hood systems capable
of exhausting in excess of 400 cubic feet per minute (0.19
m3/s) shall be mechanically or naturally provided with
makeup air at a rate approximately equal to the exhaust air
rate.


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## Chuck_M (Feb 18, 2022)

steveray said:


> M1503.4 Makeup air required. Exhaust hood systems capable
> of exhausting in excess of 400 cubic feet per minute (0.19
> m3/s) shall be mechanically or naturally provided with
> makeup air at a rate approximately equal to the exhaust air
> rate.


Yes but they need to exhaust the air to need a make up air lol

I'm trying to get them to exhaust first lol


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## Genduct (Feb 18, 2022)

steveray said:


> M1503.4 Makeup air required. Exhaust hood systems capable
> of exhausting in excess of 400 cubic feet per minute (0.19
> m3/s) shall be mechanically or naturally provided with
> makeup air at a rate approximately equal to the exhaust air
> rate.


Regular Kit Hood,  no where near 400 CFMs  regular infiltration more than enough for incidental use


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## Chuck_M (Feb 21, 2022)

What is the process to have a clarification with the code officials?


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## Genduct (Feb 21, 2022)

Chuck_M said:


> What is the process to have a clarification with the code officials?


Just a simple phone call  OR BETTER suggest they join the Forum !  Now that remark will need a a sense of humor from the Code Official.  Just say you didn't knw yourself and the info from forum was pretty simple


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