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TOPIC: Ceiling Fans

Ceiling Fans 27 May 2003 11:22 #28219

  • take2
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Could anyone tell me if there is a rule of thumb for the size of a ceiling fan in ratio to the amout of air that it will circulate? How many fans are needed for how much space ect.?
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Re: Ceiling Fans 27 May 2003 18:24 #28220

  • Ken Layton
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Don't forget that ceiling fans make a certain amount of noise when in operation. After they've been in operation a few months they start to squeak and somebody has to climb up there to clean all the globs of dust off.
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Re: Ceiling Fans 28 May 2003 08:08 #28221

  • John Pytlak
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Be careful not to position the fans under ceiling lights, as the rotating blades will cause a very annoying flicker.

John P. Pytlak, Senior Technical Specialist
Customer Technical Services
Entertainment Imaging
Research Labs, Building 69, Room 7525A
Eastman Kodak Company
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Telephone: 585-477-5325 Cell: 585-781-4036 Fax: 585-722-7243
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John P. Pytlak, Senior Technical Specialist
Customer Technical Services
Entertainment Imaging
Research Labs, Building 69, Room 7525A
Eastman Kodak Company
Rochester, NY 14650-1922
Telephone: +1 585-477-5325 Fax: +1 585-722-7243
E-Mail: This e-mail address is being protected from spambots. You need JavaScript enabled to view it
Website: http://www.kodak.com/go/motion
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Re: Ceiling Fans 28 May 2003 12:21 #28222

  • Mike
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John points out a true fact and for some the flicker can actually induce an epilepsy event.

We use at least two in each theatre and they do help. We have had no noise problem but like everything else in this world you do have to clean the things.

Michael Hurley
Impresario
Michael Hurley
Impresario
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Re: Ceiling Fans 28 May 2003 13:39 #28223

  • John Pytlak
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Mike wrote:

"John points out a true fact and for some the flicker can actually induce an epilepsy event. "

I know, because my wife has epilepsy. Our church has ceiling fans mounted right below the ceiling flood lights, and the flicker makes her feel queasy (although no seizures).

John P. Pytlak, Senior Technical Specialist
Customer Technical Services
Entertainment Imaging
Research Labs, Building 69, Room 7525A
Eastman Kodak Company
Rochester, NY 14650-1922
Telephone: 585-477-5325 Cell: 585-781-4036 Fax: 585-722-7243
E-Mail: This e-mail address is being protected from spambots. You need JavaScript enabled to view it
Website: http://www.kodak.com/go/motion
John P. Pytlak, Senior Technical Specialist
Customer Technical Services
Entertainment Imaging
Research Labs, Building 69, Room 7525A
Eastman Kodak Company
Rochester, NY 14650-1922
Telephone: +1 585-477-5325 Fax: +1 585-722-7243
E-Mail: This e-mail address is being protected from spambots. You need JavaScript enabled to view it
Website: http://www.kodak.com/go/motion
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Re: Ceiling Fans 28 May 2003 21:29 #28224

  • Alysa
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The AMC theater here in “beautiful downtown Burbank” has ceiling fans installed. They were very inconspicuous as they were painted non-reflective black, inaudible, and mounted close to the black ceiling.

Since there is only sidewall scone lighting in the theater, no ceiling light was “blinking” down on the audience so as to induce a seizure IMHO (but I’m not an expert on seizures).

The theater was probably 700-capacity and I would guess the fans were 48-52” – but it’s only a guess. I only noticed the fans at all because I always look closely at the design of the theaters I visit.

I watched the fans as the movie played and could see no reflection from the fan blades – maybe it was the blade’s “angle of attack”, as pilots would say.

Alysa
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Re: Ceiling Fans 28 May 2003 21:58 #28225

  • Roger
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There is a single screen theatre in the state of Connecticut that has ceiling fans. One of the fans squeaks constantly when it is on and wobbles as if it is about to fall on the heads of those below at any second. This is the only theatre I've ever seen with ceiling fans and I'm scared to sit anywhere in the vicinity of those fans!
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Re: Ceiling Fans 29 May 2003 00:00 #28226

  • RoxyVaudeville
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Most of the large theatres built back in the 20s had ceiling fans under the balcony. However,in those days they weren't there to circulate the heat but rather as a cooling device, before air-conditioning came about.
They also had them in the lobbies as well. I remember as a kid, one of our large downtown theatres still had those fans, and yes they did wobble, and I too was scared to walk or sit under them as I was sure I would be eligible for a part as the headless horseman before the end of the show.
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Re: Ceiling Fans 29 May 2003 01:05 #28227

  • Avalon
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I use three ceiling fans in my auditorium. Even tho I am going to real, live a/c soon, the fans are staying. I believe there is code that states they are supposed to be tethered to the mount with a cable or the like -- so ck on that before you install. It is better to add more fans, reduce the speed of the blades rather than make fewer fans do more work by running them faster. The slower they go, the less noise. Also, all of my fans have a diagonal support that helps stabilize them so if they pick up a wobble or get turned up, they don't make as much noise. It also is one more thing to keep them from ever leaping from the ceiling and making for my customers! Always start with new fans. Don’t salvage fans from another building or something like that. Don’t ask me how I know this . . . .but, it is a rare event that a ceiling fan is removed from a ceiling where something doesn’t get bent – and you discover it after you’ve done the installation. BTW, those cheap, efficient industrial fans are useless in an auditorium – no speed control and they are LOUD.
Paul Turner
Avalon Cinema
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Re: Ceiling Fans 30 May 2003 04:42 #28228

  • Big Guy
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Ceiling Fans? In an auditorium? Sounds crazy to me! I have never seen them, and have never seen a need for them! A good A/C unit that is well maintained won't need any, and it seems like a distraction, no matter how quiet or slow they may be!
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Re: Ceiling Fans 30 May 2003 08:36 #28229

  • Ken Layton
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Ceiling fans are mostly used in theaters with high ceilings such as old single screens (particularly with a balcony). Some theater operators just can't afford a full HVAC system or retrofitting would involve extensive modifications to a historic building so ceiling fans are the only option. Never use 'home' style ones in a commercial business like a theater because they don't hold up to commercial use. Plus they either fall apart (yikes!), squeak, or crap out.
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Re: Ceiling Fans 30 May 2003 09:15 #28230

  • take2
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Thanks to all of you for some great input. This site continues to amaze me. Everyone is so willing to help and give valuable information.
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Re: Ceiling Fans 31 May 2003 21:33 #28231

  • Adam Fraser
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We have 6 five foot or so cieling fans in a 450 seat auditorium with 40 foot cathedral cielings. They help circulate the air right before we open. We do have a/c but it sure does help the air get down to where it is needed. Also does the same with heat. Although you cant see them too well in the pic, you can see one in the upper left corner. http://www.pinestheatre.com/theatre2.jpg
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Re: Ceiling Fans 02 Jun 2003 11:13 #28232

  • jimor
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While fans are far from the best means to move air for all the reasons mentioned and more, if one is going to use them he had best find high quality ones from such commercial suppliers as W.W. Grainger Co. see: www.Grainger.com Look there under BROWSE PRODUCTS>HVAC>FANS>AIR CIRCULATING. In their print catalog (obtainable by proving that you are a business)is a section of Reference pages with one labeled: "FAN LAWS"; your question about ratio of air movement may be answered there (can't find my copy or would tell you myself). If that does not help you, notice on Grainger's site the RESOURCES secition with 'Certification Information' link to HVAC organizations, all of which have various sorts of information available. The "Machinist's Handbook" may also include such a table.
There is a chapter in the 'text book' for movie palaces, "American Theatres of Today" by Sexton (1930) {find it through Inter-Library loan at your library, or look for it by title at www.Amazon.com )about Heating and Ventilation of the theatre which discusses the desired Cubic Feet per Minute of air movement (regardless of heating or cooling) that is desireable for any theatre. In some jurisdictions, the CFM is dictated as a certain minimum according to the building or occupancies codes. Check local authorities.

Fans were used in older theatres since the turn of the century, but were gladly outmoded with the arrival of dependable air cooling which in most theatres was forced by huge blowers in the basement or attic using the "Downflow" system (the Upflow system results in cold feet during air conditioning) as described in American Theatres of Today. With the advent of true air conditioning after the second World War, the dew point of the air could be reduced so far as to make relative humidity comfortable, not just cooler, and fans were completely outmoded, since these freon-based systems were run as Blowers year 'round and were virtually noiseless.

When the freon systems were installed as retrofits in most theatres back then, they always disabeled the original Washed-Air system which had used carbon dioxide or amonia coolers to chill the air without dehumdifying it. Almost always the original blowers were then re-wired to be on only when the compressors or heaters were on, so continual, healthy air movement became a thing of the past. With the building of much smaller Cinemas (as compared to the vast cubic feet of Movie Palaces of thousands of seats) cheaper 'Unit' systems were installed having blowers plus heaters/coolers integrally mounted, and with a minimum of branch ductwork. While the makers advertised these as the successors to the old Washed-Air systems where sprays of water continuously sprayed through the stream of incoming outdoor air and the air was then chilled to remove most of the humidity, then heated if necessary to counteract the cooling, these new Units were no where near the ability to produced the clean, washed air that the Palaces enjoyed. Of course, the Units' cost was also FAR less than the huge Washed-Air systems!

No one advocates trying to reactivate the old Washed-Air systems today, since the upkeep and costs are prohibitive, sad to say, but to rely on fans for most all air movement is not a good idea. Fans do deteriorate much faster than a blower and are not nearly as efficient. They do wobble somewhat depending upon the type of mounting, since some have ball joint mounts that are designed to allow them to wobble somewhat, since that reduces stress on the fan and its mounting. Yes, in all cases, a steel safety cable (chains tend to rattle) should be installed from the superstructure to the fan stem below the mount, since tragic failures of fans as they fell have been recorded. As always, it pays to buy the best fan that your funds allow, if you are convinced that fans are the way to go. Some theatres which want more air movement have made quiet 'Air Risers' by putting a vertical duct on the floor and mounting it to the wall (using suitable cosmetics: paint or panels) where it terminates near the ceiling. They put a blower (surplus blowers are often available from local furnace repair men) in the bottom of the unit behind a grille, and force the air either up or down, as needed by season (some blowers are reversible). Depending upon the size of the room, one or two of these may be cheap and effective with no droped parts hazard and much less noise if the blowers are properly pad mounted, and the ducts curved to avoid Venturi effects.

If you have an old theatre with the ventilators under the seats or in the risers, by all means try to reactivate them, since they were designed to provdide ideal air circulation to every patron. You may have to pull the old Washed-Air spray racks out of the plenum chamber in the basement, but it is a small cost compared to the benefits gained. If the old fans(s) are too difficult to re-motor, if needed, then consider using a framework supporting several blowers wired to work in unison.
Those so-called 'mushroom vents' under the seats also often permitted many items to fall into the plenums under the seats and therefore are often a rich treasure trove of old programmes, play bills, and patrons' items lost over the years. Be sure to take a flash light and crawl down as far as you can, but never alone. If you are re-doing the place and have such vents, you might save yourself some headaches by putting steel hardware cloth over the openings to prevent other things going down there (and vermin from crawling up!) Putting chew-proof steel mesh behind all vent grilles will discourage mice and rats from making a home in your theatre, where the smell of popcorn is irrestible to them.
Finally, do not believe a contractor or salesman who says that the fans will be perfect for your place and will never make noise; great pains were taken in the design of the movie palaces to keep motors and any other such noise makers away from the audience, in fact, many of the large ones had concrete or pyrobar roof decks to keep out outdoor noise, as well. If your ceiling is low, try to avoid fans completely.

Further information may be available from The League of Historic American Theatrs: www.LHAT.org or from the Theatre Historical Society of America: www.HistoricTheatres.org The League maintains listings of specialists/contractors in most building categories whom you may consult informally on-line or professionally (for a fee). Best Wishes.
Jim Rankin, member THSA since 1976
P.S. Just found this link for a $90 book on ceiling fan air movement. It is an engineering text, so may be at a local tech school, and you can always ask for it on Inter-library loan through your local library. http://resourcecenter.ashrae.org/store/ashrae/newstore.cgi?itemid=8568&view=item&categoryid=174&page=1&loginid=243568

[This message has been edited by jimor (edited June 02, 2003).]

[This message has been edited by jimor (edited June 04, 2003).]
Jim R. (new E-mail: This e-mail address is being protected from spambots. You need JavaScript enabled to view it ) member: www.HistoricTheatres.org
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