# Make up air requirement



## Sifu (May 9, 2012)

Way, way, way out of practice on this since we don't enforce it here but I got a question today about a hood.  Person installing a hood over two electric fryers, doesn't know the specs exactly yet but wanted to know the make up air requirements.  Can the make up air be through a simple transfer grill sized to match the exhaust rate of the hood?  Or, does it need to be integral to the hood or within a certain distance of the hood?  Even though I don't enforce it here, if they want to ask I want to give them the correct info.


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## globe trekker (May 9, 2012)

From Section 508 in the 2006 IMC:

*508.1 Makeup air. *

Makeup air shall be supplied during the operation of commercial kitchen exhaust

systems that are provided for commercial cooking appliances. The amount of

makeup air supplied shall be approximately equal to the amount of exhaust air.

The makeup air shall not reduce the effectiveness of the exhaust system. Makeup

air shall be provided by gravity or mechanical means or both. For mechanical

makeup air systems, the exhaust and makeup air systems shall be electrically

interlocked to insure that makeup air is provided whenever the exhaust system

is in operation. Makeup air intake opening locations shall comply with

*:Next('./icod_imc_2006f2_4_sec001_par003.htm')'>Sections 401.4* and *Section 401.4.1.*



Makeup Air can be of the gravity type or the mechanical type. If using

mechanically generated Makeup Air, the system must have an interlocking

fan switch to operate simultaneously (i.e. - fan pulling outside air in while

the hood exhaust fan is operating).

From Section 506.3.1.2 in the 2006 IMC:

*Makeup air ducts.*

Make up air ducts connecting to or within 18 inches (457 mm) of a Type I

hood shall be constructed and installed in accordance with :Next('./icod_imc_2006f2_6_sec003.htm')'>*Sections 603.1**,*

*:Next('./icod_imc_2006f2_6_sec003_par002.htm')'>603.3**, **:Next('./icod_imc_2006f2_6_sec003_par003.htm')'>603.4**, **:Next('./icod_imc_2006f2_6_sec003_par019.htm')'>603.9**, **:Next('./icod_imc_2006f2_6_sec003_par020.htm')'>603.10* and *:Next('./icod_imc_2006f2_6_sec003_par022.htm')'>603.12.* Duct insulation installed

within 18 inches (457 mm) of a Type I hood shall be noncombustible or

shall be listed for the application.


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## klarenbeek (May 9, 2012)

Makeup air does not have to be provided within a certain distance of the hood, just into a space that communicates through permanently open openings into the space with the hood. For instance, a restaurant with a pass-through opening between the dining room and kitchen can use outside air taken in through the dining room hvac units for makeup air, as long as the units are interlocked to run when the hoods run. Just make sure the minimum outdoor air settings are set to what they say is coming in through the unit


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## fireguy (May 10, 2012)

But the make-up air intake is to be 10 feet from the exhaust fan.  Actually, any exhaust air is to be 10 feet from the make-up air intake.  Including vent pipes for plumbing, toilet room vents.  Inspector wrote me up for that error once, but only once.

The mechanical code also lists the air movement required for the electric fryers, and gives a formula to determine the exhaust air movement.


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## Sifu (May 10, 2012)

Everything everyone says makes sense.  Got a little more info this AM.  The fan will move 300 CFM.  ( I don't know for sure but by the brief description I assume it is a wall mounted canopy) Sounds like if they install an air transfer grill in the same area or within a communicating space sized to allow the same amount of air movement located remote from any exhuast (at least 10' away) it would be acceptable.


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## Gregg Harris (May 10, 2012)

Sifu said:
			
		

> Everything everyone says makes sense.  Got a little more info this AM.  The fan will move 300 CFM.  ( I don't know for sure but by the brief description I assume it is a wall mounted canopy) Sounds like if they install an air transfer grill in the same area or within a communicating space sized to allow the same amount of air movement located remote from any exhuast (at least 10' away) it would be acceptable.


Take a look at IMC 403.2.2 and 403.3


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## cda (May 10, 2012)

also require a balance test

507.16 Performance test. A performance test shall be conducted

upon completion and before final approval of the installation of a ventilation system serving commercial cooking

appliances. The test shall verify the rate of exhaust air flow required by Section 507.13, makeup air flow required by Section

508, and proper operation as specified in this chapter. The permit holder shall furnish the necessary test equipment and devices

required to perform the tests.

507.16.1 Capture and containment test. The permit

holder shall verify capture and containment performance of

the exhaust system. This field test shall be conducted with

all appliances under the hood at operating temperatures.

Capture and containment shall be verified visually by observing

smoke or steam produced by actual or simulated

cooking, such as with smoke candles, smoke puffers, etc.


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## Sifu (May 10, 2012)

Can't require anything here.  We don't enforce any commercial codes.  Scary thing is, this little convenience store could have put in the fryers with no hood, or a hood with no air, or suppression, or anything.  Fortunately they purchased and hired a professional system and installer.  They just called me to see if they had to put in the interlocked air (they didn't know we had no codes) or if to make it less expensive they could use the ambient air.  I told them infiltration air wouldn't do it but I thought transfer air would.  Even after I told them I had no enforcement capabilities they still wanted it to meet the minimum code, for which I am appreciative, what they end up doing I won't know unless I go buy a piece of chicken!  BTW my BO overheard the conversation about commercial cooking and exhaust and I was afraid his head would pop off.  (if you've read some of my other sagas you know what I'm talking about)


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## mtlogcabin (May 10, 2012)

This is a big one in this part of the country. Don't know how big an impact it will have in TN.

508.1.1 Makeup air temperature.

The temperature differential between makeup air and the air in the conditioned space shall not exceed 10ºF (6ºC) except where the added heating and cooling loads of the makeup air do not exceed the capacity of the HVAC system.

Any system installed in an existing building will have a negative effect on the HVAC sytem and the energy bills of the building if the makeup air is not part of the hood design.


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## Gregg Harris (May 10, 2012)

mtlogcabin said:
			
		

> This is a big one in this part of the country. Don't know how big an impact it will have in TN.508.1.1 Makeup air temperature.
> 
> The temperature differential between makeup air and the air in the conditioned space shall not exceed 10ºF (6ºC) except where the added heating and cooling loads of the makeup air do not exceed the capacity of the HVAC system.
> 
> Any system installed in an existing building will have a negative effect on the HVAC sytem and the energy bills of the building if the makeup air is not part of the hood design.


This is one of the "bad verbiage" changes made for 2009


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## cda (May 10, 2012)

Sifu said:
			
		

> Can't require anything here.  We don't enforce any commercial codes.  Scary thing is, this little convenience store could have put in the fryers with no hood, or a hood with no air, or suppression, or anything.  Fortunately they purchased and hired a professional system and installer.  They just called me to see if they had to put in the interlocked air (they didn't know we had no codes) or if to make it less expensive they could use the ambient air.  I told them infiltration air wouldn't do it but I thought transfer air would.  Even after I told them I had no enforcement capabilities they still wanted it to meet the minimum code, for which I am appreciative, what they end up doing I won't know unless I go buy a piece of chicken!  BTW my BO overheard the conversation about commercial cooking and exhaust and I was afraid his head would pop off.  (if you've read some of my other sagas you know what I'm talking about)


"""Even after I told them I had no enforcement capabilities """"

where are you at Washington DC???????


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## Sifu (May 10, 2012)

mtlogcabin said:
			
		

> This is a big one in this part of the country. Don't know how big an impact it will have in TN.508.1.1 Makeup air temperature.
> 
> The temperature differential between makeup air and the air in the conditioned space shall not exceed 10ºF (6ºC) except where the added heating and cooling loads of the makeup air do not exceed the capacity of the HVAC system.
> 
> Any system installed in an existing building will have a negative effect on the HVAC sytem and the energy bills of the building if the makeup air is not part of the hood design.


So if I understand what this says a simple transfer grill allowing in cold air in the middle of winter would not seem to fit the bill.......unless they account for it in the HVAC system?  Am I reading that right?  Does that come from 09?  06 gives the exception for "air that does not decrease the comfort conditions of the space" that itself seems a bit arbitrary doesn't it?


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## mtlogcabin (May 10, 2012)

Yes it is from the 09 but the same lanquage is in the 06 code.


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## Sifu (May 11, 2012)

mtlogcabin said:
			
		

> Yes it is from the 09 but the same lanquage is in the 06 code.


2006 IMC

508.1.1 Makeup air temperature. The temperature differential

between makeup air and the air in the conditioned space

shall not exceed lOoP (6°C).

Exceptions:

1. Makeup air that is part ofthe air-conditioning system.

2. Makeup air that does not decrease the comfort conditions

of the occupied space.

#2---The air can be greater than 10 degree difference if it doesn't make you uncomfortable.  Why write a specific code if you turn around and give it such an arbitrary exception?  One mans too cold is another mans just right!


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## Darren Emery (Oct 23, 2012)

To continue this a bit:  there is a sentence in the commentary that says:  "Rarely if ever would the need arise to cool the make up air."  If the goal of this section is employee comfort (as stated in the comentary) why would you NOT want to cool the make up air stream when it is 100+ outside?  If the MUA is entering the kitchen environment, and it's 110 outside (and perhaps 120+ on the roof) that kitchen AC is going to have a heck of a time handling all that extra heat load.

We have focused on heating the MUA for years now...perhaps its time to consider the cooling side as well, what with global warming and all.


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## mtlogcabin (Oct 23, 2012)

Heating the air is more than employee comfort it also contributes to emplyee health. Standing over a hot stove and having 15 or 20 degree air blowing down your neck is a good way to catch a cold. Cooling the MUA is a requirement of 508.1.1 and is probably a good idea in KS and other areas where the summer temps can get really high for prolong weeks or months.


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