[CAUT] Heating system volume level

[Fred Sturm]

Hi TIm,
	My question would be just exactly what are you dealing with. You talk  
about an HVAC unit in the room. My building has centralized fans (some  
in basement, some in "attic") that force air through ducts throughout  
the building. There are two duct systems, one for relatively hot, one  
for relatively cold air, with mixing boxes for individual rooms or  
sets of rooms. The thermostats control the mix, using air pressure  
(from the constant flow of air) to set baffles to let in more of one  
or the other. The baffles are old and get stuck. Sometimes there is  
whistling or a sound like a gale if one gets stuck not quite closed.  
THen there is fan noise that can get transmitted through the ductwork.  
Lots of different things that can cause noise.
	But it sounds like you have the actual fan motor in the room with you  
in your system. Or do you? In any case, the first step is to find out  
exactly what you have, mechanically.
	It is quite possible to have excellent HVAC sound baffling for  
individual areas (like concert halls or recording studios). Our  
recording engineer had a studio built 10 years ago, and got amazing  
silence. So I know it can be done. Sometimes it is a matter of the  
right person asking the right question of the right person. There's  
the rub: finding that right person. And it does cost money.
Regards,
Fred Sturm
University of New Mexico
fssturm at unm.edu

PS (other post): Yes, I went to school with Fernando Ortega. He was  
nuts about Brahms at the time, as I recall. Is he based in your area?


On Sep 25, 2008, at 6:02 AM, Tim Coates wrote:

> I have appreciated the comments from this list.  I have also  
> contacted some educators who have dealt with noisy HVAC units in  
> class rooms and rehearsal  rooms.  Proper air handling, turning off  
> the units during rehearsal, moving the HVAC units outside the room  
> to the roof, and staying on good terms with the janitors and  
> engineers are consistent comments.  One other solution is the use of  
> an in-room PA with the instructor using a headset.  One band  
> director reported students requesting the continued use of the  
> headset even after the noisy HVAC unit was removed from the room.   
> The headset allowed the instructor to never use a raised voice.   
> Which when you think about it can change the tone or character of a  
> rehearsal.  No yelling.  The relationship between the students and  
> the instructor became conversational.   The wear on the instructors  
> voice also affects their physical energy.
>
> My major concern:  voices or instruments need to blend together to  
> make music.  Noisy HVAC units prevent the blending.  I think side  
> effects are teachers with hoarse voices and students who don't hear  
> directions properly.
>
> Tim Coates