Film-Tech Forum ARCHIVE: fly lofts and heating costs

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Posted by Scott Norwood (Member # 30) on 01-13-2003, 04:23 PM:

For those who have dealt with older theatres with full stage facilities, but which normally only show films: what's the best/easiest/cheapest way to avoid having to pay to heat the entire fly loft during the winter?

One option would be to keep the fire curtain closed (to act as insulation) and turn off all heating facilities backstage (or leave them set very low). Unfortunatley, this means that the screen would need to be located in front of the fire curtain, which would preclude the use of the traveler and moveable side masking. Also, it would mean that the loudspeakers would need to be placed above or below the screen instead of behind it.

Does anyone have any other ideas? Or do these places all just have to eat the extra heating costs in the winter?

Posted by Steve Guttag (Member # 268) on 01-13-2003, 05:47 PM:

Scott,

For the most part, it is a non-issue. It doesn't cost squat to heat/cool air...it is the stuff with mass that costs the money. I'd be surprised to find that the area above the stage, without some form of forced heating/cooling is at the same temp as the auditorium proper. In case of a fire, the fly space is supposed to have exhaust fans and dampers that open up.

Personally I wouldnt' worry about it...unless you want to permanently close off the fly gallery.

Steve

Posted by Ian Price (Member # 14) on 01-13-2003, 06:32 PM:

At the Mayan Theatre in Denver Colorado they had a sound problem with the sound reverberating in the fly loft. So what they did was build a sort of THX wall using duct liner to mitigate the sound problem. As a result it was always 10-20 degrees cooler on stage, which wasn't being used.

It's an idea!

Posted by Jeff Sirles (Member # 1511) on 01-13-2003, 06:37 PM:

We show only movies at out old theaters, so we have false insulated ceilings at our "fly loft". Basically its just a regular suspended ceiling with insulation above it. Looks as though it was pretty easy and cheap to put up....but also somewhat permanent. So, if you use the "fly loft" I might not reccomend that.

Posted by Ken McFall (Member # 845) on 01-13-2003, 08:52 PM:

I recall in Scotland at the cinema I managed that we had a problem with air movment from the stage area. We didn't have a fly area as such but a similar space above the stage.

Winthin a few minutes of the heating being turned on the main curtain would bellow out and the draught was very noticable. So much so that we would get complaints from the stalls area when the curtains were closed as the air flow was directed at head height into the stalls.

Once the curtains were opened the draught was less noticable. We tended to leave the curtains open until the public were admitted.
We installed some extra radiators but were never able to compleatly eliminate the problem. We were given some prices to eliminate the problem but they were prohibitive. So we just had to live with it.

Posted by Paul G. Thompson (Member # 655) on 01-13-2003, 08:58 PM:

Get some paddle fans and keep the air moving. We did that at the Lido Theatre in Mount Vernon because all the heat stayed near the ceiling, and the customers froze their butts off unless we had the old oil furnace in overdrive.

By installing paddle fans, we reduced our oil consumption dramatically. That theatre did not have a fly loft, but I can understand there could be lots of trapped hot air that is basically wasted that could be more evenly distributed for the comfort of the patrons.

Posted by Ken McFall (Member # 845) on 01-13-2003, 09:12 PM:

Paul....

can we get these fans fitted on here..... [Eek!]

Posted by Richard C. Wolfe (Member # 431) on 01-13-2003, 11:30 PM:

As the operator of a historic former vaudeville theatre with full stage facilities I have had to deal with the flyloft heating hassel for many many years. We still use our stage for live performances 10 to 15 times a year, and therefore can not permanently close off the flyspace. The loft is five stories tall, over twice the height of the auditorium, which of course it must be to fly the screen, curtains and any other backdrops or scenery used in a live show. The stage floorspace represents about 20% of the building, but due to the height it represents 33% of the cubic feet of the building. It does therefore, add a tremendous about to the heating cost of the building.

About thirty years ago when I was running the theatre on weekends only for a short period I decided to close the fire curtain during the week while the theatre was closed so that I would only be heating the auditorium and not the stage. I turned the thermostat down to 50 degrees during the week when closed. As the thermostat was located in the auditorium it was satisfied much quicker with the stage being closed off. As steam still went to the backstage radiators, there was still heat back there to the point that nothing would be in jeopardy of freezing. On the first Friday that I reopened I pulled the fire curtain up in mid afternoon to allow the theatre temperture to even itself before opening time. What happened then I was not prepared for to say the least. The warm air in the auditorium rushed through the proscenium arch and up into the flyloft with hurricane force. The cold air backstage rushed down and out into the auditorium with the same velocity. The stage curtain was literally blown into the auditorium and flapped against the ceiling. Luckily for me no damage was done to the curtain, and as the temperture adjusted the curtain settled back to where it belonged. A lesson learned... I never did that again.

If you want to keep the screen a proper distance from the seating, and therefore keep it on the stage, and keep the stage treatment in view, you can build a shadowbox around and over the screen. This is simply a wall behind the screen which turns at each end and proceeds forward until butting up against the proscenium wall. A ceiling is then installed over this boxed area and the screen, masking, and curtain are all usuable while most of the stage is sealed off from use and not stealing expensive heat. In order to limit the size of this box so as to keep heating costs down as much as possible, the stage speakers can be behind the wall with cutouts for the speakers to be set up against. I have seen this done successfully in many stage theatres with a tremendous savings in heating costs. Usually enough to pay for the cost of the shadowbox in less then one season.

My problem is that since we still use the stage, what can I do? I designed an insulated lightweight flyable wall to go behind the screen with holes for the speakers. Also hinged lightweight insulated walls to swing out from the proscenium to the flyable wall. The problem is how do I install a ceiling overhead with so many ropes and wires hanging all the curtain tracks, border lights etc. My plan calls for a batten with four hinged insulation panels, as we have three sets of overhead lines,that would be hung tight against the fire curtain. When up, the panels would be against the fire curtain, but when lowered they would bridge from the fire curtain back to the flyable wall behind the screen. The area between the panels where the overhead lines come through would have rubber or felt overlapping the openings thus sealing that area off as much as possible. A tiny space would of course be left for each line to go through. This plan is still on paper, as I still have yet to build it, but I think it is doable at rather small expense when compared to the rather large savings that hopefully will be had from constructing such.

Posted by William Hooper (Member # 71) on 01-14-2003, 04:12 AM:

I can't think of a theater that has a reversible system of sealing off the fly tower. But, as Richard Wolfe pointed out, you've got to be careful with thermal effects in big theaters. I've been in theaters on a hot day with the onstage load-in door open & exit doors at the top of the balcony open, & it blows a gale. I'm not really sure how much benefit would be derived, either. Unless the sealing & insulation of the proposed partition were *very* scrupulous, I don't see how it would be much different from the difference in the attic & auditorium when the HVAC is in operation in a house with a plaster & lath ceiling: there's not much.