From: "Dave Martin" <dave.martin@x?????xxxx.xxxx
Date: Fri Nov 12, 1999 4:47 am
Subject: Re: HVAC info?
>Dave, the best way to size your machine is to call the manufacturer and
>them your total cubic feet. They will then recommend a unit, and you should
>then buy the next higher size, so that you can run it at it's lowest
>plus have a little room for expansion.
Well, that's the general idea, but with a large format console and 120-140
rack spaces of equipment (much of it either tube or Class A), the heat
generated by equipment is way out of line with a typical home or office. The
last room I used for this in a basement that was approximately 15x25x7.5
feet; last winter, I never turned on a heater for that room, and during this
summer, if I turned the AC off for 45 minutes, the ambient temperature in
the room would rise to more than 85 degrees.
>As far as installing ductwork, I like the flex ducting, which is very easy
>install, and surrounded by insullation. I think it will give you far less
>headaches than galvanized ducting. As far as sizing the ducting, figure out
>what you need (you can also get this from the manufacturer), then add 20%.
>instance, if your layout and volume call for 10" ducts, get 12" ones. This
>will reduce the air velocity while keeping the circulation rate that you
Flex duct looks sensible to me, but I was told that you can't split a run
(for instance, to take the main air duct and split it to two sides of the
room) from a flex duct; it has to run off of a galvanized duct. And it looks
as though my local Home Depot sells lined flexible duct in 25 foot sections;
form the unit that I intend to use temporarily, the distance is about 30
feet. I'm not even sure how you'd connect two of them together...
I'm actually wanting to do a couple of different things; the most pressing
is to run ducts into the garage that I'm currently using as a studio, and
the other is to start gathering information for a ground up studio that I'm
>As far as books, if you find one, let me know. Where I live, it's illegal
>a homeowner to do any HVAC work. It must all be done by a licensed
>contractor. If this is a widespread policy, then it's no wonder there are
>any books on the matter.
Cliff Kaminsky, from Vibro-Acoustic Sciences, Inc. suggested
which is definitely the site for books on this subject; now I get the joy of
narrowing them down...
>Also, as it happens, I am currently finishing up an article on
>HVAC for Dan's site. It's not particuarly authoritative, instead, it's more
>a "this is how I did it" kind of thing. It might be helpful. Good luck,
I'll look forward to reading it, and thanks to all for the information.