# Air balance required on rooftop changeout?



## Jim k (Nov 7, 2016)

I was recently turned down by a city inspector on a like for like change out of an existing gas and electric roof top 2.5 ton package unit at the city's community center. The building official was interpreting building code 407.3.1 (air balance). He claims that an air balance report must be performed to prove a proper percentage of fresh air to the building when the system operates. The original fresh air intake is located on the existing ductwork. The section of the code says nothing about performing an air balance after changeout of equipment. My question is that if we adjust the fresh air intake, what does this do to the validity of the original air balance report of when the system was oringinally put in. There is also the question of if the fresh air ends up needing to be adjusted/modified, can I charge for this, in my opinion, additional work? It's just a simple 4" eyebrow without a damper control. I am not set up to do this air balance work, and will likely have to hire a third party. This was not in the written scope of work when I went to bid the change out. It seems to open up a can of worms in my opinion.


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## Rick18071 (Nov 9, 2016)

My 2009 IMC does not have that section. What codes are being used?


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## Jim k (Nov 9, 2016)

It's in the CA building code book. It's an amended section of the national code. I went into another city building department and spoke to an inspector and he thought it was far reaching to require such a thing. I'm just looking for more ammo before going back into building department.


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## mark handler (Nov 9, 2016)

Been in the CA code for years
http://www.iapmo.org/California Mechanical Code/Chapter 04.pdf


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## rgrace (Nov 10, 2016)

I would require that you set the outdoor air to what it originally was, and call it done. Replacing the RTU like for like does not change the design of the system interior. As long as the supply, return and outdoor air are equal (or at least approximately equal) to the original design, a new air balance report would serve no purpose to the equipment replacement. This is my opinion, based on the codes that I enforce in my jurisdiction. I do not know all the nuances of the CA code, but I cannot imagine that it's intent is to require a balance report for ALL equipment that is being changed out due to age or malfunction, especially if there are no interior alterations.


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## JBI (Nov 10, 2016)

It also depends on which Code editions are adopted...


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## mark handler (Nov 10, 2016)

JBI said:


> It also depends on which Code editions are adopted...


NOT TRUE IN CA
CA State law mandates that local government enforce the current California Building Standards Code *as published* by the California Buildings Standards Commission in Title 24 of the California Code of Regulations.
The codes are state law regardless of local adoption.
If the code is not adopted by the local AHJ, it is still state law.


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## JBI (Nov 10, 2016)

Mark Handler, You did not refute my post (though you may think you did). The California Code is what has been adopted, whether by consent or mandate.


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## mark handler (Nov 10, 2016)

JBI said:


> Mark Handler, You did not refute my post (though you may think you did). The California Code is what has been adopted, whether by consent or mandate.


It does not "depend on which Code editions are adopted..."
It is in the code and was in the code.


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## JBI (Nov 10, 2016)

That would be the ADOPTED Code?


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