HVAC check list

Hi All, I am having real difficulty here in Ireland finding a Air Con suitable for my studio build. Below is the mail I sent to suppliers. Some have offered fans but are not willing to stand over noise criteria and others are having difficulty with the required velocity. So there are really two q's... If possible could some one with the knowledge please look over my attachment and check am I looking for the correct specifications. Any design ideas or outlines that I could pass on to the suppliers? All input is really appreciated as I seem to have hit a dead end at the moment and all work in the control room has stopped till I get some ducts in.. Kindest regards, Joe 1. Drum room. 34m3 10 air changes per hour maximum air velocity 1.5 m/s 1.2m/s preferable Can use 1 or 2 extraction vents in walls each 4m duct run with 3 * 90 degree bends Fan located outside in covered area Flexible Acoustically Lined ducting (which can be boxed in by others) 2. Live Room 110m3 10 air changes per hour maximum air velocity 1.5 m/s 1.2m/s preferable 2 extraction vents in walls each 4m duct run with 3 * 90 degree bends Fan can be located inside with 1m run from fan to grille or external fan with 1.5m extra duct run 3. Vocal Booth 14m3 10 air changes per hour maximum air velocity 1.5 m/s 1.2m/s preferable 1 extraction point in ceiling 9m duct run with 3 * 90 bends Fan can be located inside with 1m run from fan to grille or external fan with 1.5m extra duct run 4. Control Room 77m3 10 air changes per hour maximum air velocity 1.5 m/s 1.2m/s preferable 1 extraction point in ceiling 10m duct run 3 * 90 degree bends Fan can be located inside with 1m run from fan to grille or external fan with .5m extra duct run 5. Machine Room 3m3 15/20 air changes per hour 1 extraction point in ceiling 6 m duct run 3 * 90 degree bends

Hi, I have the spec/price of this range of fans. All velocity's are between 240fpm to 280fpm. The link is to download the pdf for the live room fan. Volume is 645 cfm in imperial. The fans look good, well to me!!, but is a fan this quiet necessary for me considering it is on the other side of a 3 foot thick granite wall and all ducts have 3 90 degree bends and a phenum, or is it just right? Any input appreciated, Link to PDF. http://download.yousendit.com/B14A3244062B8BEF Joe

The sound from the fan travels through the ducts. Without doing an engineering analysis on the sound attenuation of the ducts and knowing your desired noise level in the studio, yes. you have given the right specs in terms of ventilation performance. I am guessing that you are comfortable with doing calculations. If you want to go through the exercise, the McQuay Application Guide AG31-010 provides detailed information on how to calculate acoustic performance of ventilation systems. It is directed at the designer/engineer, so it is comprehensive and assumes familiarity with math. It will take several hours to read it, absorb it, and setup your spreadsheet to do the calculations. If you do, you will have the satisfaction of knowing that you did not spend (read waste) money on more than you need. As you have found out already, quiet HVAC (north american term for Heating, Ventilation, and Air Conditioning) is very expensive. Good luck and let us know how things go! Coolly, Andre

Thanks for that Andre. It's been awhile since i've used equations of that sort so i think it will provide a little mental as well as sonic attenuation as well!! :lol: Joe