# Pull a non-fire curtain in a fire?



## Jay Ashworth (May 26, 2015)

My house has a low enough backstage ceiling (as I understand the rule) that it doesn't have a separate Fire Curtain, in addition to the horizontal-travel scene curtain.

When I start each show, I remind my LBO that if I have to call a fire evac, their job is to switch the house lights to architectural, and then get the hell out of the booth; I will make an evac announcement over the PA (I *never* work a booth without a mic in it), and then follow them.

But there's a question that was just brought to my mind by the Fire Hose thread elsewhere this week:

Do we pull the curtain? Does it help?

I'm sure it was treated in some fashion; it's a commercial proscenium curtain. It is 15 years old, and probably has never been re-treated.


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## StradivariusBone (May 26, 2015)

As I understand it, a large part of what a fire curtain does is to prevent smoke from entering the audience area, coupled with roof vents to evacuate smoke through the top of the stage creating a draft to draw all the bad air up and out which gives time to egress. I know with our main rag in the air flow around the sides of the curtain is very noticeable with the HVAC running. I'm guessing for our situation it would not serve as an adequate smoke barrier.


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## Footer (May 26, 2015)

Get your curtains retreated first. This should be done every 5 years unless they are IFR. After you have taken steps to prevent the spread of fire you can then figure out what to do if there is one. 

I wouldn't bring it in though. You would just be adding ore fuel to the ground. 

Finally, get a bull horn. Don't expect your PA to work in an emergency.


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## BillConnerFASTC (May 26, 2015)

I don't think the time it would take to close a house curtain would be worth it (unless it was a fire and this made it possible to extinguish). It does bring a potential combustible (don't believe that flame retardant does much) closer to the audience, probably a bad thing.

If your vents in the stage roof had a manual means to open them from the stage floor - as is required by building and fire codes but probably not ever installed a lot of times - the time to open them would be much more useful to protecting the occupants. The automatic opening - heat detectors or fusible links - are unlikely to open the vents before everyone has egressed.

No fire safety curtain of the types commonly installed in the US, let alone a plain main curtain, will stop smoke from spreading into the auditorium if there is positive pressure on stage. If there is negative pressure, it is not needed to stop smoke. (So I am saying it's useless, but that story for another day.) The best way to achieve negative pressure, or at least keep the neutral pressure plane over the stage above the proscenium opening or that point at which smoke will roll into the auditorium are vents or exhaust high. This was well understood by the Austrians when they investigated the 1881 Ring Theatre fire in Vienna Austria as well as the work done by an engineer after the Iroquois Theatre fire. (See "On the Safeguarding of Life in Theatres" bu John Freeman PE - free on google books and elsewhere.) A fire at the Frankfurt opera house in mid 1980s - trying to find the source photos and article and my report but this was practically pre-personal computer and in one 40 or so file boxes in my house - where the robust and heavily steel framed fire safety curtain as well as the 3 hour metal man-doors in the proscenium wall all buckled in a lot as a result of the negative pressure on stage.


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## venuetech (May 26, 2015)

http://www.oper-frankfurt.de/en/page651.cfm
16 ton iron curtain?


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## BillConnerFASTC (May 26, 2015)

I think the safety curtain at the Royal Opera House in 
London is more like 25 tons.

On Frankfurt, soon after the fire I spoke with Michael Yeargan who had been on the stage the day before the fire. I was able to get plans of scenery but suffice it to say it was a "bare stage" design with very little scenery on stage reported.

Important to keep in mind that this stage and most or many stages in Europe are not sprinklered. (In fact, many fewer buildings are sprinkle red in Europe overall.)


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## venuetech (May 26, 2015)

Are there any reports of Fire on sprinklerd stages?


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## StradivariusBone (May 26, 2015)

"The closed 16 ton iron curtain glowed red."

Iron glows red around 900° F. That is the most terrifying thing ever.


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## BillConnerFASTC (May 26, 2015)

venuetech said:


> Are there any reports of Fire on sprinklerd stages?


I know of two. Both new - one opened a year and one in final checkout - like hours to clean up for a gala that evening - both lights fouled with ( new flame retardant treated) curtains - both fires extinguished by one sprinkler. One was not a real tall stage, other a road house. The sprinkler under gridiron did not open, one under roof deck right above did its job.


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## BillConnerFASTC (May 26, 2015)

StradivariusBone said:


> "The closed 16 ton iron curtain glowed red."
> 
> Iron glows red around 900° F. That is the most terrifying thing ever.


It is steel, not iron. That's just what they call it, like steel pipe is called black iron pipe.

There was a drencher system as well in Frankfurt, water spraying the stage side. Kind of wonder who thought to put sprinklers on stage side. Photo showed it sort of dangling.


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## StradivariusBone (May 27, 2015)

Well, steel's about the same in that regard. That's flashover level heat, and judging by the description of how the building sort of exploded shortly after that I'm guessing that's what happened once air was let into the flytower. I just can't imagine the energy to sustain that level heat in a space that large and drawing such a vacuum to feed that fire. 

Do you know why the drencher system was ineffective in the Frankfurt case?


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## BillConnerFASTC (May 27, 2015)

I don't know how long the drencher operated if at all, but it was supported from the roof and I'm sure it failed when the roof caved in.


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## techieman33 (May 27, 2015)

venuetech said:


> http://www.oper-frankfurt.de/en/page651.cfm
> 16 ton iron curtain?



My fire curtain is just shy of 20 tons. It's original to the 1940 construction. It was refurbished in the early 90s when the building was changed from a flat floor arena to a performing arts center. From what I've been told the asbestos filler was removed and replaced with something else. An acoustic face was also added for an orchestra to perform in front of.


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## StradivariusBone (May 28, 2015)

techieman33 said:


> My fire curtain is just shy of 20 tons. It's original to the 1940 construction. It was refurbished in the early 90s when the building was changed from a flat floor arena to a performing arts center. From what I've been told the asbestos filler was removed and replaced with something else. An acoustic face was also added for an orchestra to perform in front of.



How do they rig those at that weight? More robust hardware or a completely different design?


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## BillConnerFASTC (May 28, 2015)

I'm working on one that's has over 6 tons of counterweight and not sure how much the water hydraulic drive lifts, replacing drive with an electric motor. 5 lift lines - 1/2" or larger wire rope - 36" head block and 24" loft blocks. Bothered I can't put an estop on it.


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## techieman33 (May 28, 2015)

StradivariusBone said:


> How do they rig those at that weight? More robust hardware or a completely different design?




BillConnerASTC said:


> I'm working on one that's has over 6 tons of counterweight and not sure how much the water hydraulic drive lifts, replacing drive with an electric motor. 5 lift lines - 1/2" or larger wire rope - 36" head block and 24" loft blocks. Bothered I can't put an estop on it.



Bill pretty well hit it on the head. There is a whole lot of counter weight, I'm not really sure what the exact total is. Then there is an electric motor that goes into a gear reduction drive. That is connected by chain to a sprocket that is the same size and attached to the head block for further gear reduction. There are 5 1/2 lift lines attached to the curtain itself. It takes a little over a minute to raise or lower via the motor. Or should power go out or if you really want to punish someone the motor can be disconnected and you can do it by hand. There is a 10" long handle that attaches to the gear reduction drive and you crank until your arms fall off and then someone else takes over. I've never been around for that luckily. It happened once before I got there and I was told it took at least 4 guys switching off every couple of minutes an hour to raise it the full 25 feet.


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## teqniqal (May 29, 2015)

Well, here is a picture of a 4-Ton counterweight, so you can just imagine what a 16 or 25-Ton arrangement looks like . . .


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## techieman33 (May 29, 2015)

teqniqal said:


> Well, here is a picture of a 4-Ton counterweight, so you can just imagine what a 16 or 25-Ton arrangement looks like . . .View attachment 12089



You wouldn't want the counter weight to match the fire curtain though. I'm sure there is a lot of math involved to get the counter weight just right. You want the curtain to fall when it's triggered, I think the weight is more to help control the speed of it's decent then to actually help balance the weight of the system. And just for giggles here is a video of my curtain coming down during a test a couple of years ago.


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## BillConnerFASTC (May 29, 2015)

techieman33 said:


> You wouldn't want the counter weight to match the fire curtain though. I'm sure there is a lot of math involved to get the counter weight just right. You want the curtain to fall when it's triggered, I think the weight is more to help control the speed of it's decent then to actually help balance the weight of the system. And just for giggles here is a video of my curtain coming down during a test a couple of years ago.



As I noted, the weight is the counterweight plus the drive. There may be a lot of math but in the end, its release and time, and add or remove some weight, until the decent is the desired or required speed.

The videod curtain clearly seems to have a dash pot or similar to slow at end of travel. A lot today simply govern the speed the whole way.


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## Jay Ashworth (May 29, 2015)

I assume that cranking it back up at that weight is a cast iron son of a bitch, if you'll pardon the pun.


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## BillConnerFASTC (May 29, 2015)

loft block and head block


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## BillConnerFASTC (May 29, 2015)

and the estimated 12,700 pound counterweight - (28" X 9" weights 13'-4" tall)


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## techieman33 (May 29, 2015)

BillConnerASTC said:


> As I noted, the weight is the counterweight plus the drive. There may be a lot of math but in the end, its release and time, and add or remove some weight, until the decent is the desired or required speed.
> 
> The videod curtain clearly seems to have a dash pot or similar to slow at end of travel. A lot today simply govern the speed the whole way.



It does have a dash pot. My understanding was that you wanted it to slow down that few feet. That way it bought a little more time for someone to clear out from under it, and so that it had a softer landing on the stage itself. I can't find it now but there used to be a page on Clancys site that said a curtain should take ~15 seconds to drop to a few feet above the deck and then another 10 to actually come in contact with the deck.


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## egilson1 (May 29, 2015)

Based on NFPA 80 and the ANSI standard there is no longer a overall time that the curtain must close by (use to be 30 seconds.) It's now based on feet per second. The speed must be no slower than 1 foot per second and the last 8' must take no less than 5 seconds. This allows for those ginormous framed curtains to move at a speed that won't be impossible to stop when it hits the deck.


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## BillConnerFASTC (May 29, 2015)

But most designed and installed today are motorized and simply governed at a constant speed, was my point.


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## techieman33 (May 29, 2015)

BillConnerASTC said:


> But most designed and installed today are motorized and simply governed at a constant speed, was my point.



So what happens if the building loses power and the fire curtain needs to come down?


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## egilson1 (May 30, 2015)

The motor is used to raise the curtain. Once at trim a break holds it in place and power is no longer needed, just like a chain motor. The difference is the break can be released by the fire line or other means and that deploys the curtain without the need for power.


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## BillConnerFASTC (May 30, 2015)

Clutch being slightly more descriptive than brake but yes, the drive holds it up and than is disconnected for release.

With the removal of the requirement for fusible links, it will be interesting to see if the cut line goes away. Alarm style pull stations and heat detectors and wire in conduit. So long Rube Goldberg.

As to control and free fall, it bothers me there is no e-stop, no way to intervene if its a false trip and and someone or something is in the path.


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## derekleffew (May 30, 2015)

egilson1 said:


> Once at trim a break holds it in place




BillConnerASTC said:


> the drive holds it up and than is disconnected


'Tis a pity grammar is not a required component of the ETCP rigging exam.


"...Gets tied up," get it?



What does one call a rigger who can't make multiple lines into one?

Clew-less.


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## chausman (May 30, 2015)

Wouldn't an estop add a lot of complication to a system that should be pretty fool proof? And isn't the possibility of someone in the way the reason many slow down for the last part of the drop? I'd also argue that a large red estop plunger would attract the attention of someone even moderately excited about some sort of emergency on stage. I'd be worried someone trying to do the right thing would end up preventing the fire curtain from dropping when needed.


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## BillConnerFASTC (May 30, 2015)

I'm just more worried about people getting injured and property damaged, which by anectdotal evidence has occurred, than I am worried it might not be all the way down in a fire, because there is no evidence I've seen that a fire safety curtain has ever prevented an injury or death from fire. Plus, just lowering the proscenium opening height could help, as it lowers the point smoke can roll into an audience because its further below the neutral pressure plane.

You worry about someone stopping it when they shouldn't, and I worry about someone starting it. A 5 ton plus fsc is going to be over 1000 pounds curtain heavy, so if you're under it, whether your crushed in 1 second or 3 seconds seems irrelevant, as you are crushed and no one could stop it.

Never forget these were invented to save property. Last one out closes it and when the stage burns down in the middle if the night, you save the auditorium. Well, once upon a time that was the case, when stage and auditorium were two separate buildings. Today, one going is going to destroy the other. We've forgotten the past.


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## StradivariusBone (May 31, 2015)

Speaking of anecdotal, one of the PAC's in our area has a curtain that deploys when the fire alarm activates, regardless of whether it was triggered by anything near the theatre or not. It is a fiberglass curtain, but has crushed and broken a few music stands in its lifetime and at least one incident with a student who was under it, watching it deploy without any clue as to what it was or why it was doing that.

I would wager in our age of safety and interlocks and e-stops, more people are inclined to think that machines in their environment (simple or otherwise) will at least stop before potentially maiming them.


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