# Vent a hood duct



## cda (Jan 13, 2014)

Can the duct pass through a fire wall or rated floor/ceiling assembly??

Can give section reference either ibc or IMc 2009


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## mark handler (Jan 13, 2014)

http://www.thebuildingcodeforum.com/forum/commercial-mechanical-codes/12873-domestic-kichen-exhaust-duct-multifamily.html


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## cda (Jan 13, 2014)

so decoding, this sections allow it?

SECTION 716 DUCTS AND AIR TRANSFER OPENINGS

716.1 General. The provisions of this section shall govern the protection of duct penetrations and air transfer openings in assemblies required to be protected.

716.1.1 Ducts that penetrate fire-resistance-rated assemblies without dampers. Ducts that penetrate fire-resistance-rated assemblies and are not required by this section to have dampers shall comply with the requirements of Sections 713.2 through 713.3.3. Ducts that penetrate horizontal assemblies not required to be contained within a shaft and not required by this section to have dampers shall comply with the requirements of Sections 713.4 through 713.4.2.2.

713.2 Installation details. Where sleeves are used, they shall be securely fastened to the assembly penetrated. The space between the item contained in the sleeve and the sleeve itself and any space between the sleeve and the assembly penetrated shall be protected in accordance with this section. Insulation and coverings on or in the penetrating item shall not penetrate the assembly unless the specific material used has been tested as part of the assembly in accordance with this section.

713.4 Horizontal assemblies. Penetrations of a floor, floor/ceiling assembly or the ceiling membrane of a roof/ceiling assembly not required to be enclosed in a shaft by Section 708.2 shall be protected in accordance with Sections 713.4.1 through 713.4.2.2.

713.4.1.4 Dissimilar materials. Noncombustible penetrating items shall not connect to combustible materials beyond the point of firestopping unless it can be demonstrated that the fire-resistance integrity of the horizontal assembly is maintained.

HOW about an actual fire wall??

from nfpa 96

7.7.1 Duct Enclosures.

7.7.1.1 In all buildings where vertical fire barriers are penetrated, the ducts shall be enclosed in a continuous enclosure extending from the first penetrated fire barrier and any subsequent fire barriers or concealed spaces to or through the exterior, to maintain the fire resistance rating of the highest fire barrier penetrated.

7.7.1.2 In all buildings more than one story in height and in one-story buildings where the roof-ceiling assembly is required to have a fire resistance rating, the ducts shall be enclosed in a continuous enclosure extending from the lowest fire-rated ceiling or floor above the hood, through any concealed spaces, to or through the roof, to maintain the integrity of the fire separations required by the applicable building code provisions.

7.7.1.3 The enclosure shall be sealed around the duct at the point of penetration of the first fire-rated barrier after the hood, to maintain the fire resistance rating of the enclosure.

7.7.1.4 The enclosure shall be vented to the exterior of the building through weather-protected openings.

7.7.1.5 The continuous enclosure provisions shall not be required where a field-applied grease duct enclosure or a factory-built grease duct enclosure (see Section 4.3) is protected with a listed duct-through-penetration protection system equivalent to the fire resistance rating of the assembly being penetrated and where the materials are installed in accordance with the conditions of the listing and the manufacturer's instructions and are acceptable to the authority having jurisdiction.

7.7.2 Enclosure Fire Resistance Rating and Enclosure Clearance.

7.7.2.1 Fire Resistance Rating.

7.7.2.1.1 Buildings less than four stories in height shall have an enclosure with a fire resistance rating of not less than 1 hour.

7.7.2.1.2 Buildings four stories or more in height shall have an enclosure with a fire resistance rating of not less than 2 hours.

OR:::

7.1 General.

7.1.1 Ducts shall not pass through fire walls.

7.1.2* All ducts shall lead directly to the exterior of the building, so as not to unduly increase any fire hazard.

7.1.3 Duct systems shall not be interconnected with any other building ventilation or exhaust system.


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## fireguy (Jan 13, 2014)

I stole this from http://www.eng-tips.com/threadminder.cfm?pid=184

The reason that kitchen exhaust ducts are prohibited from passing through fire walls is:

 1) You cannot provide a damper in a kitchen exhaust system due to the operating temperatures. Therefore, if the duct is compromised for whatever reason, a passage for fire extension from one side of the wall to the other is created.

 2) I'm not sure what building code is in effect on your project. If the project is in the US, it is most likely subject to compliance with the International Building Code. A major concern for any through-penetration is that the penetration may pull down the fire wall in the event the structure collapses. If this project is subject compliance with the International Mechanical Code, it prohibits kitchen exhaust duct penetration of fire wall

 3) From a practical standpoint, I've seen horizontal ducts on kitchen hood system and while they are allowed, they are a PITA (pain in the *****) from a fire safety perspective because they are more difficult to clean. NFPA 96 has extensive ITM requirements, including established cleaning and inspection frequencies. Over the service life of the duct, if it begins to sag, ponding of proteins and oils will occur in the low point(s), and these are commonly missed by cleaning technicians.

 Finally, site coordination is a pretty crappy basis for deciding that compliance with a nationally recognized standard for fire protection is not important. I sincerely doubt the jurisdiction would agree with this interpretation but I don't know the knowledge base of the enforcing jurisdiction.

The author said it better than I could.  The only thing I could add is concerning horizontal ducts.  Not only are they difficult to clean, but normally the access panels for horizontal duct are not accessable themselves.  If they are accessable, the way the panels are insulated, the insulation comes off, and gets thrown away.  One brand of panel has a problem with the glue that holds the gasket in place. The glue deteriorates and allows the gasket to leak.  We install    http://www.flamegard.com/products/subcategory/?category=4    Easy to install, the gasket withstands the temps and the grease.

If you see this http://www.ductmate.com/product.aspx?id=13 acess door with the red knobs, it is not listed for use in a grease duct.  the gasket is foam rubber.  These are often installed by HVAC contractors who do not know grease ducts.  My solution, remove the panel, get the hose welded and install a new panel that is listed for the grease ducts.

Back to the access issue.  During the inspection process, ask a couple of hood cleaners to come in and ask them if the panels are accessable.   Remember, after the hoods & ducts are installed, someone will put cabinets, and other appliances in the kitchen that will make the access panels not accessable.


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## steveray (Jan 13, 2014)

705.11 Ducts and air transfer openings.

Ducts and air transfer openings shall not penetrate fire walls.

Exception: Penetrations by ducts and air transfer openings of fire walls that are not on a lot line shall be allowed provided the penetrations comply with Sections 712 and 716. The size and aggregate width of all openings shall not exceed the limitations of Section 705.8.


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## cda (Jan 13, 2014)

OK, so we can not go through a fire wall

How about going vertical, through say rated floor/ ceilng assemblies


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## steveray (Jan 13, 2014)

Probably just has to be enclosed in a rated shaft that matches the assembly penetrated..


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## Dr. J (Jan 14, 2014)

Let's be sure what you are asking.

If by "Vent a hood" you mean a residential grade hood above a residential grade (and utilized) appliance, then the duct is just an everyday duct, not Type I Commercial Kitchen Hood Duct.  If so, then you don't need to apply the requirements for a Commercial Kitchen Hood Duct, it is no different than a fart fan.

If it is a Type I Commercial Kitchen Hood Duct, then a rated enclosure and a whole lot more is required.

If by fire wall you mean Fire Wall, then see steveray's response.

If by fire wall you really mean Fire Barrier, then review exception 3 to 716.5.2 to see if a fire damper is required.  If you can't meet the exception for a fire damper and say "well what about the grease buildup", then go back to my first "if by" - if you are worried about grease buildup, it should be a Type 1 Commercial Kitchen Hood Duct.

For the rated floor/ceiling assembly, see IBC 716.6.1; particularly the exception.  This is meant specifically for things like fart fans, dryer vents, and range hoods in low-rise buildings.


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## cda (Jan 14, 2014)

Commercial vent a hood

Already quoted you cannot go through a "fire wall"

But say a four story building that for whatever reason has rated floor/ ceiling assemblies??

Can you go vertical through all the rated floors and roof??


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## Dr. J (Jan 14, 2014)

What is a commercial vent a hood?


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## cda (Jan 14, 2014)

Dr. J said:
			
		

> What is a commercial vent a hood?


Ok type I

Not one in a house or apartment in a restaurant


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## Dr. J (Jan 14, 2014)

There are a whole lot of requirements for a Type 1 Commercial Kitchen Hood Duct, see IMC ch 5.  Among the requirement is that the duct be in a rated enclosure from the hood to the exterior.  The enclosed duct is essentially a shaft, and one of the purposes is to extend the fire area of origin directly to the exterior.  Thus any penetrations of fire restive construction is inherently protected by that enclosure/shaft.

The Fire Wall question is interesting. A Fire Wall (as opposed to a Fire Barrier) creates two separate buildings. Why do you have a Fire Wall in a restaurant?  Recall that a Fire Wall is expected to be structurally independent of either building, allowing either side to collapse while the Fire Wall remains standing.  How would you create an enclosure that could do that? Probably should avoid a Fire Wall, stay in the building you start in.


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## cda (Jan 14, 2014)

Dr. J said:
			
		

> There are a whole lot of requirements for a Type 1 Commercial Kitchen Hood Duct, see IMC ch 5.  Among the requirement is that the duct be in a rated enclosure from the hood to the exterior.  The enclosed duct is essentially a shaft, and one of the purposes is to extend the fire area of origin directly to the exterior.  Thus any penetrations of fire restive construction is inherently protected by that enclosure/shaft.The Fire Wall question is interesting. A Fire Wall (as opposed to a Fire Barrier) creates two separate buildings. Why do you have a Fire Wall in a restaurant?  Recall that a Fire Wall is expected to be structurally independent of either building, allowing either side to collapse while the Fire Wall remains standing.  How would you create an enclosure that could do that? Probably should avoid a Fire Wall, stay in the building you start in.


just trying to give an example

was given the section that says no Fire Wall::

705.11 Ducts and air transfer openings.

 Ducts and air transfer openings shall not penetrate fire walls.

 Exception: Penetrations by ducts and air transfer openings of fire walls that are not on a lot line shall be allowed provided the penetrations comply with Sections 712 and 716. The size and aggregate width of all openings shall not exceed the limitations of Section 705.8.

Now the question is does IBC allow you to go vertical through rated assemblies?????

if which section


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## JBI (Jan 14, 2014)

There is an exception, but it is not applicable to your project/scenario.

*607.6 Horizontal assemblies. *

Penetrations by air ducts of a floor, floor/ceiling assembly or the ceiling membrane of a roof/ceiling assembly shall be protected by a shaft enclosure that complies with Section 713 and Sections 717.6.1 through 717.6.3 of the _International Building Code _or shall comply with Sections 607.6.1 through 607.6.3.

*607.6.1 Through penetrations*In occupancies other than Groups I-2 and I-3, a duct constructed of _approved _materials in accordance with Section 603 that penetrates a fire-resistance-rated floor/ceiling assembly that connects not more than two stories is permitted without shaft enclosure protection provided that a _listed _fire damper is installed at the floor line or the duct is protected in accordance with Section 714.4 of the _International Building Code. _For air transfer openings, see Exception 7, Section 712.1.8 of the _International Building Code._


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## cda (Jan 14, 2014)

JBI said:
			
		

> There is an exception, but it is not applicable to your project/scenario.*607.6 Horizontal assemblies. *
> 
> Penetrations by air ducts of a floor, floor/ceiling assembly or the ceiling membrane of a roof/ceiling assembly shall be protected by a shaft enclosure that complies with Section 713 and Sections 717.6.1 through 717.6.3 of the _International Building Code _or shall comply with Sections 607.6.1 through 607.6.3.
> 
> *607.6.1 Through penetrations*In occupancies other than Groups I-2 and I-3, a duct constructed of _approved _materials in accordance with Section 603 that penetrates a fire-resistance-rated floor/ceiling assembly that connects not more than two stories is permitted without shaft enclosure protection provided that a _listed _fire damper is installed at the floor line or the duct is protected in accordance with Section 714.4 of the _International Building Code. _For air transfer openings, see Exception 7, Section 712.1.8 of the _International Building Code._


doe any of this apply???

SECTION 716 DUCTS AND AIR TRANSFER OPENINGS

716.1 General. The provisions of this section shall govern the protection of duct penetrations and air transfer openings in assemblies required to be protected.

716.1.1 Ducts that penetrate fire-resistance-rated assemblies without dampers. Ducts that penetrate fire-resistance-rated assemblies and are not required by this section to have dampers shall comply with the requirements of Sections 713.2 through 713.3.3. Ducts that penetrate horizontal assemblies not required to be contained within a shaft and not required by this section to have dampers shall comply with the requirements of Sections 713.4 through 713.4.2.2.

 713.2 Installation details. Where sleeves are used, they shall be securely fastened to the assembly penetrated. The space between the item contained in the sleeve and the sleeve itself and any space between the sleeve and the assembly penetrated shall be protected in accordance with this section. Insulation and coverings on or in the penetrating item shall not penetrate the assembly unless the specific material used has been tested as part of the assembly in accordance with this section.

 713.4 Horizontal assemblies. Penetrations of a floor, floor/ceiling assembly or the ceiling membrane of a roof/ceiling assembly not required to be enclosed in a shaft by Section 708.2 shall be protected in accordance with Sections 713.4.1 through 713.4.2.2.

713.4.1.4 Dissimilar materials. Noncombustible penetrating items shall not connect to combustible materials beyond the point of firestopping unless it can be demonstrated that the fire-resistance integrity of the horizontal assembly is maintained.


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## JBI (Jan 22, 2014)

Basically the options are enclose in a shaft or provide dampers.

(unless of course your point is to keep asking about random code sections until you get the answer you want?)


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## cda (Jan 22, 2014)

JBI said:
			
		

> Basically the options are enclose in a shaft or provide dampers. (unless of course your point is to keep asking about random code sections until you get the answer you want?)


No down to if say four floor building

Floor ceiling assembly is rated

Can a vent a hood duct go vertical through all three floors and through the roof

Legally by code ???


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