Smart questions
Smart answers
Smart people
Join Eng-Tips Forums
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Member Login




Remember Me
Forgot Password?
Join Us!

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips now!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

Join Eng-Tips
*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.
Jobs from Indeed

Link To This Forum!

Partner Button
Add Stickiness To Your Site By Linking To This Professionally Managed Technical Forum.
Just copy and paste the
code below into your site.

Help with windowless home theater room - remove toxins

cgott42 (Computer) (OP)
3 Jan 11 18:39
I hope that this is the correct forum (came across it via google).
I have a windowless room that in my basement that I've converted into a home theater/exercise gym (I exercise while watching).   The room is approx. 12x26' and does not have any windows.  Further, I've insulated it well to keep the sound from the movies trapped inside the room so as to not disturb those outside of it.

As mentioned unfortunately it doesn't have windows (came that way) and today I broke 2 CFL screw in bulb in the room - so naturally I'm worried about mercury exposure.

Please see the attached pic as to the layout.  
How can I ventilate this room - being that there aren't any windows in the room?
Preferably something which is (a) inexpensive (b) can be covered/plugged so that sound doesn't escape the room while watching a movie (3) Preferably (though not critical, just trying to save costs) something which I can install myself (though I don't have much more than screwdriver skills) - despite being used as a home theater - it doesn't look pretty so aesthetics aren't an issue.

Thanks!!
cgott42 (Computer) (OP)
3 Jan 11 18:40
Also forgot to mention, there are no ducts or HVAC, of soffits in the room.
MikeHalloran (Mechanical)
3 Jan 11 23:37
I can't address the mercury issue.

For ventilation, you can add air channels with acoustic labyrinths, one for air going in, one for air going out.
They can be similar.

A simple but effective acoustic labyrinth looks vaguely like a simple periscope; a rectangular tube of some length, say floor to ceiling, with openings on opposite faces at opposite ends.  The one for incoming air can have a fan on the regular basement end, say at the bottom of a plywood tube.  You could put an air diffuser on the home theater end at the top to spread the air out.  Similarly for the one removing air from the theater, but it may not need a fan.  It still needs a hole, of course.

The trick is the acoustic lining.  Good stuff comprises 1/2" of urethane foam, 1/8" of lead-loaded plastic sheet, and another 1/2" of urethane foam, bonded to the inside faces of the plywood tube with contact cement.  A cheaper alternative would substitute ordinary galvanized steel sheet for the lead-loaded plastic.  It can be in pieces, without rigid corner connections, i.e., it doesn't have to be a proper duct all by itself; it just has to cover most of each flat surface.   

The net inside cross sectional area at any transverse section of the tube should equal or exceed the flow area of the fan.  A rectangular section is probably better than a square one, and takes less space away from the actual basement.

If the sound absorption of the tube is insufficient, add baffles parallel to the airflow, comprising galvanized steel sheets with foam on both sides.  In the limit, they would form a number of parallel air passages about 1 or 2 inches in transverse/least dimension, resembling a commercial bread slicer with thick soft blades.

Such baffles/grillages are sold commercially for yacht engine rooms, where they allow almost unimpeded flow of combustion air, and suppress engine noise (that's at a nearly painful level) to levels that allow a conversation with ease just outside the bulkhead.  They are typically not more than a foot 'thick' in the axial direction.

Sorry, I have no design data for such stuff, so it will have to be cut and try unless someone else comes up with equations or numbers.


 

Mike Halloran
Pembroke Pines, FL, USA

cgott42 (Computer) (OP)
4 Jan 11 9:40
thx
chicopee (Mechanical)
6 Jan 11 21:35
Since your theater walls are of cinder block construction, you could easily remove one block from each adjacent wall and install louvers as remotely as possible from each other for forced make up air inlet and for exhaust outlet. Duct your forced make up air  with a low profile duct from the wall opening to about one foot off the ground. Install louver without duct for exhaust.
Mercury permissible exposure level(TLV's) can be obtained from the American Industrial Hygienist pamphlet on PEL's; also research the internet for that value.   

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!

Back To Forum

Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close