HVAC and air changes per hour

max · Post by **max** » Wed Dec 21, 2005 5:00 pm

Hello all,

I was hoping somebody could point me in the right direction with this HVAC concern.
I'm building a recording studio in Melbourne, Australia. It will run as a business so it must comply with safety standards, however I'm having trouble finding out how many air changes per hour I need in my otherwise airtight (hopefully) performance room.

The performance room dimensions are 4860mm length X 3120mm width X 2440mm height, which gives me a cubic capacity of 37m.
I'd think that things in the room that generate heat and consume oxygen would have to be factored into this query. There would be no more than eight people in there at any given time, and no more than six speaker cabinets (though usually a lot less).

I'm not installing air conditioning as the place stays cool during summer. My main concern is:
At what rate should fresh air be pumping into the room?
At what rate should carbon monoxide/stale air be pumped out of the room?

Any help would be greatly appreciated.

Max Anceschi

Post by **sharward** » Wed Dec 21, 2005 5:12 pm

The answer is different depending on your township. Here in the states, we have many model codes, with different release dates, so two cities next door to each other could have different (albeit similar) requirements.

Your best bet is to determine what codes are in effect in your township and consult with the building department there.

At least, that's how we do it over here.

Hope that helps...

--Keith

WiseMindsRecordingStudios · Wed Dec 21, 2005 5:41 pm

I guess I would ask what kind of equipment you are running that creates Carbon MONOXIDE?

Post by **sharward** » Wed Dec 21, 2005 5:53 pm

I think he meant carbon dioxide. The equipment that produces that is human beings.

max · Post by **max** » Wed Dec 21, 2005 9:32 pm

Yes, Sharward is correct - carbon dioxide expelled from humans.

knightfly · Post by **knightfly** » Fri Dec 23, 2005 4:11 pm

Hopefully, that's the UN-scented Co2 we're talking about...

Here's a basic guideline, barring any interference from local "BRA's"

http://www.warmair.com/html/air_to_air_exchangers.htm

And more -

http://www.nibs.org/BETEC/Fall00.PDF

HTH... Steve

Post by **sharward** » Fri Dec 23, 2005 4:39 pm

knightfly wrote:Here's a basic guideline, barring any interference from local "BRA's"

http://www.warmair.com/html/air_to_air_exchangers.htm

That page contains the following statement above the calculator:

"A properly sized Air Exchanger will completely replace the air inside your house a total of 6 times per day."

If you are using mechanical ventilation to make up for the lack of windows in a studio, you will probably need to completely replace all the air inside the rooms a total of 2 or 3 times per hour when activated. Your mileage may vary -- check with your local building department.

knightfly · Post by **knightfly** » Sat Dec 24, 2005 1:53 pm

Yeah, noticed that; IIRC the other link was better on that. Most stuff I've seen wants 2-3 changes per hour. I think maybe that 6 per day thing was more of an "extra" for a house or something; no code I've seen is that lax, although there does seem to be quite a range depending on usage of the space... Steve

Post by **sharward** » Sat Dec 24, 2005 4:51 pm

Yup... City of Boise, Idaho, requires 3 changes per hour, but my town requires 2. In any event, it's best to find out what the local BRAs* require.

*BRAs = Bureaucrats Run Amok, as Steve would say...

max · Post by **max** » Tue Jan 03, 2006 7:19 pm

thankyou very much for pointing me in the right direction

Post by **sharward** » Wed Jan 04, 2006 2:18 am

knightfly wrote:I think maybe that 6 per day thing was more of an "extra" for a house or something . . .

Yes, "extra" for a house with windows. For living space that has no windows, code requires something a bit short of a DC-9 jet engine to move the air in and out.

(I exaggerate... But the point is made!)