# Fire Alarm



## jerekb (Oct 30, 2008)

So we are having a haunted house in our auditorium to raise money. In this we have a fog machine in the pit and then last night me, in all my brilliance decided to put one in the house. As the people walked through the fog they carried it to the back of the house where it caught an ungodly draft and was carried straight up right in front of me on the balcony and right into the rafters . We were in the middle of discussing the possibility of the fire alarm going off when sure enough, they went off. As there was only 2 groups remaining we went a head and called it a night after the FD cleared the building. So today during second period we had a fire drill. What a coincidence.


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## willbb123 (Oct 30, 2008)

I work in an old theater that has burnt down once. So the theater has "a highly sensitive fire alarm system" I like to use haze for every concert that I can. We have to make sure that we get water based haze because mineral based will set of the alarm.


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## TheDonkey (Nov 2, 2008)

Overall, fog nor haze should set off most alarms, most of them actuallt look for the chemicals in smoke, so fog machines only set off the Optical ones, which apparently aren't overly used.

But yeah, having to shut down for a fog machine is a terrible thing, we were doing a haunted house in my schools drama studio and luckily didn't set off any alarms, but after 3 hours the fog got so thick it refused to air out in the 5 minute intermissions we had every half hour. So the graveyard effect we had going where fog oozes up from behind gravestones didn't look quite right.


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## 2damax (Nov 2, 2008)

How would you go about shuting off the fire alarms for a theatre. If you have a simplex fire alarm system. the fire alarm goes off from haze and fog.


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## coldnorth57 (Nov 2, 2008)

You can NOT shut off the fire alarm EVER in a theatre, BUt you can check out fire alarm system that do not use smoke to check for fire but uses heat


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## avkid (Nov 2, 2008)

2damax said:


> How would you go about shuting off the fire alarms for a theatre. If you have a simplex fire alarm system.


An administrator would need to talk to the fire marshal and Simplex.

You would most likely need to have the fire marshal or a representative of the fire department present when the system is off.


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## GreyWyvern (Nov 3, 2008)

avkid said:


> An administrator would need to talk to the fire marshal and Simplex.
> 
> You would most likely need to have the fire marshal or a representative of the fire department present when the system is off.



Having worked with pyro effects on tour, I know there are certain procedures that need to be followed if a fire alarm system needs to be shut off. Usually, there does need to be someone from the fire department there the entire time the system is shut off, and typically the entire building has to be walked and every room checked every half hour or so. However, codes and regulations and restrictions vary from state to state and country to country, so check with your local authorities.


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## Balo (Nov 3, 2008)

We have a simplex(far from simple) system in our theatre. The Facilities Engineers worked out a bypass with the Fire Marshall that disables the smoke sensors and not the heat sensors in our system for 1 hour to allow the use of smoke effects. We can reset it every hour, but that also ensures that someone is in the building when the smoke effects are in use. The most recent addition to our bypass is the need to call our public safety office to let them also know we're bypassing the system or they send 2 officers to investigate. 

There are ways around them, you just have to check with your fire marshall and see what he's willing to do because smoke effects aren't going away any time soon.


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## Sony (Nov 3, 2008)

At my old High School they had a system where they could turn off the detectors but leave all the pull stations active so if someone saw a fire they could still sound the alarm. Unfortunately at the high school I work at and the college I go to this isn't possible and they both use Optical sensors which means we can't used water or mineral based fog at all...

The High school I work at has all of the detectors in the ventilation system, we have no visible detectors. They are Laser type detectors where if anything disturbs the lasers (smoke or fog) the alarm goes off. The return vents are in the front of the apron of the stage so any smoke or haze on stage immediately gets sucked into the return vents and activates the alarm...it's a horrible design for a theatre. 

My college has optical smoke detectors in the ceiling and it's a very small space so there is no NOT getting the smoke into them...it's annoying. Luckly at my college they are in the process of installing a brand new fire system in the building...hopefully the new system wont be so sensitive.


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## TimMiller (Nov 7, 2008)

I hate laser sensors. I once set one off at a church by climbing up on a ladder to change a bulb. What a PITA, you have to call the Fire Dept every time you change a light bulb to come out a disable the system, could it get any more stupid.


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## WestlakeTech (Nov 11, 2008)

Before our Fine Arts Facility went under construction, we would regularly rent it out. A small handful of students would run the shows for $10/hr. About a year (maybe year and a half) ago, one of our regular renters, a dance school, was putting on a performance. It was either the first or second time to perform, when in the middle of track 7 the fire alarm goes off.

We evacuate EVERYONE! That's over 1000 people when you add up crowd and dancers. So the fire department shows up (being a school, they're immediately and automatically alerted when any of our alarms sound) and take a look at things. Turns out to be a false alarm and we continue the show once everybody gets back in the FAF.

So it's all over, right?... Nope. 7 or 8 tracks later, alarm goes off again. Facilities Director said one of the alarms in another part of the school was broken, but that was thankfully the last time the alarm would go off that night. In fact, I haven't heard it since. However, we have had an "In case the fire alarm goes off" talking-to at almost every show since then.

One of those moments you hate at the time but you look back on and laugh eventually.


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## renegadeblack (Nov 13, 2008)

Does anyone else see the irony in hoping that new fire alarms will be less sensitive?


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## willbb123 (Nov 13, 2008)

They dont have to be less sensitive. they just have to be more intelligent, to be able to tell the difference between haze and fire.


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## Sony (Nov 13, 2008)

there are some really intelligent ones nowadays that can actually sense the ionization of air that happens just before a fire ignites...of course that would mean no more fire or pyrotechnics on stage ether. That and they are incredibly expensive...mostly used in Datacenters and Stuff like that. 

I don't think there will ever be a perfect solution other then being able to turn off certain zones. I personally like the idea of being to turn the detectors off and leaving the pull stations active. If that means having one person near a pull station at all times on fire alarm duty then so be it.


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## WestlakeTech (Nov 13, 2008)

Lucky for us, both of our pull stations (one in each wing) have fusable links which any fire will melt causing the curtain to drop. So even if no one's there, we're not completely up the creek. But I do still like the idea of someone always being there just in case.


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## Sony (Nov 13, 2008)

At MVPAC we were supposed to have a system that automatically dropped the fire curtain anytime the alarms went off. However that system was never completed because the fire alarm system is connected to the same system as the high school which has a false alarm pretty much every week. So now it's just a Fuseable Link system. We were also supposed to have a douser bar connected to the sprinkler system but that was never finished...


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## TRRHINO (Nov 15, 2008)

TheDonkey said:


> Overall, fog nor haze should set off most alarms, most of them actuallt look for the chemicals in smoke, so fog machines only set off the Optical ones, which apparently aren't overly used.



I would have to disagree... We have tried everything in our theatre. It seems the best way to not make the fire alarm go off is to just cover it with a plastic cup with some good old gaff tape around it... Works like a charm every time... (we have smoke detectors not optical)


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## Anonymous067 (Nov 15, 2008)

I have a question:

In our theater, backstage left and right, we have a little glass box that says "break glass and pull in case of fire". But its not a pull-station, (theres those right next to it), and a cable is attached to it going up into the flys. What does this do?


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## maccalder (Nov 15, 2008)

Eeegads... You should never ever ever ever ever cover sensors with a plastic cup. Frankly, if there is not a proper procedure for isolation of smoke detectors (ionisation/optical sensors are the ones you need to isolate), then I am sorry, but you should not be using atmospherics.

There are a number of different types of fires sensors - and each one is optomised for certain things (there are also hybrid sensors which contain a mixture of the lot). The four main types you will run into are Particle(Ionisation), Optical, Heat, Rate of Rise

Only two of these will be set off by atmospherics - the particle (ionisation) and optical sensors. Ionisation will detect any ionised particles caused by combusion and the other two rely on heat. Now the issue with RoR and Heat is that in a venue with high ceilings (think theatre) heat based sensors which are normally installed in the ceiling take a good while to go off (RoR less than Heat). 

Ionisation alarms are the type normally found in homes and are prone to false alarm - most venues with decent fire prevention systems will not use these.

Basically a decent venue will use a combination of optical and either RoR or Heat, and will have a FCP somewhere where the optical sensors can be deactivated or put into a non-alarm state of some description. If your local authority finds covered detectors, then someones head WILL roll.


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## elite1trek (Nov 15, 2008)

Blah067 said:


> I have a question:
> 
> In our theater, backstage left and right, we have a little glass box that says "break glass and pull in case of fire". But its not a pull-station, (theres those right next to it), and a cable is attached to it going up into the flys. What does this do?



This is probably the release for a fire curtain.

By pulling that, you would release a curtain that will come in, most likely directly US from the proscenium. The fire curtain is designed to keep fire and heat (and sometimes smoke) from spreading into the house from the stage, or vice-versa, in the event of a fire.


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## Sony (Nov 15, 2008)

Blah067 said:


> I have a question:
> 
> In our theater, backstage left and right, we have a little glass box that says "break glass and pull in case of fire". But its not a pull-station, (theres those right next to it), and a cable is attached to it going up into the flys. What does this do?



It's the manual release for the Fire Curtain. Every modern theatre with a proscenium arch is required to have a Fire Curtain. There are most likely also Fuseable links somewhere in the system that will release the fire curtain automatically if the temperature rises above 150 degrees.


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## Chris15 (Nov 16, 2008)

Wow. It seems installers down here think a lot more about how spaces are going to be used. The normal thing in a venue is to get the venue techs to go and isolate the relevant zone of the alarm. So you might isolate the sensors inside the auditorium but leave all others turned on. This may however cause you grief if you have leakage to a backstage corridor etc that is non isolated. The bigger venues have documented procedures in place that cover the process they go through when a sensor is triggered. This usually involves some form of verification. Sure I would expect fire and smoke doors to have their electromagnetic holds released the moment something went off, but in a big enough venue, people will be assigned to check the source of an alarm and then the venue's emergency management (normally security and other such parties) will make a decision on the best way to proceed. If it's found to be a false alarm, they won't evacuate. If it can be managed, they will manage and if they need to evacuate then they will.

It is important to remember that in some cases the panic etc caused by an evacuation can cause problems. In large venues, having a system in place whereby staff are alerted first and then open the outer exit doors and position themselves before a calm announcement is made can be the difference between an evacuation that is successful and one that is a complete shambles, potentially involving injuries from tripping or whatever.

The whole idea behind a fire curtain and in most cases associated smoke vents in the roof is to literally turn the stage and fly tower into a chimney. The stage will flare up, get out of there FAST but it will provide negative pressure to the auditorium which should then allow enough time to evacuate the auditorium safely. In some cases, dependent on the original design, the fire curtain may not come all the way to the floor. In some cases it is designed to come all the way down and to seal the stage in which case it is not creating a chimney, it's acting as a fire retarding wall.

In any case it is important to have documented procedures in place to cover what happens in the event of a fire and what options are available for isolating the fire alarms in part or full. These documents should be signed off on by the relevant people in your organisation for OH&S, insurance etc as well as the relevant people to your organisation for fire compliance, which varies from country to country, state to state and more locally. Very few venues have the luxury of being their own Authority having Jurisdiction, though I do know of one in my part of the world.

I recall vaguely having written on this or a very closely related topic before. It should be in the archives somewhere.

Oh and you should want more sensitive detectors, but with a control system coupled with relevant procedures to allow for them to be temporarily isolated. People discussed laser systems. It is important to note there are 2 types. One relies on an infrared beam across the space, be sure to have these isolated before getting a ladder out. The other is a good bit more sensitive and expensive. It's known as a VESDA, an acronym for Very Early Smoke Detection Apparatus. I think it may also be known as an aspirating smoke detector in some circles. It works by continually drawing air in from the space through a pipework system and using a laser to monitor that air for so much as trace amounts of smoke. These can be sensitive enough to pick up a smouldering fire that has not yet progressed to the stage of producing easily visible smoke. But you pay for this extra warning time...

As always, consult someone experienced / qualified / licenced / insured as appropriate when working these things out. It then becomes their behind on the line not yours should anything go wrong...


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## photoatdv (Nov 17, 2008)

Sony said:


> It's the manual release for the Fire Curtain. Every modern theatre with a proscenium arch is required to have a Fire Curtain. There are most likely also Fuseable links somewhere in the system that will release the fire curtain automatically if the temperature rises above 150 degrees.


And ours just falls randomly sometimes... and other times some stupid kid thinks its part of something else and pulls that rope

Seriously, we've had people out to fix it SO MANY TIMES. I think they finally got it fixed though. It fell last year on our musical and our pro guy, after putting a pipe in it so we could finish rehearsal, insisted that they have real riggers (not the district facilities people) come out to fix it. Turned out that it was out of weight. The really strange part was that they were sure it hadn't been reweighted in at least a few years (because of the dust on the plate). Anybody know how a fire curtain magically changes weight?

The good news is that supposedly if somebody pulls it now, we can just put it back up.


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## willbb123 (Nov 17, 2008)

photoatdv said:


> And ours just falls randomly sometimes... and other times some stupid kid thinks its part of something else and pulls that rope
> 
> Seriously, we've had people out to fix it SO MANY TIMES. I think they finally got it fixed though. It fell last year on our musical and our pro guy, after putting a pipe in it so we could finish rehearsal, insisted that they have real riggers (not the district facilities people) come out to fix it. Turned out that it was out of weight. The really strange part was that they were sure it hadn't been reweighted in at least a few years (because of the dust on the plate). Anybody know how a fire curtain magically changes weight?
> 
> The good news is that supposedly if somebody pulls it now, we can just put it back up.



We need to re-weight or curtains and other soft goods because of the change in humidity. I'm actually going to go in today and check each line set. We had a union crew in a week ago, they loaded weight onto the wrong arbor, so we almost had an electric run away....


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## Wallab (Nov 22, 2008)

coldnorth57 said:


> You can NOT shut off the fire alarm EVER in a theatre, BUt you can check out fire alarm system that do not use smoke to check for fire but uses heat



In our auditorium I always go and switch off the fire alarm(we have an optical one) before every show where haze/fog is used. There is a control box with a key that you can turn it off.


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## museav (Nov 29, 2008)

Wallab said:


> In our auditorium I always go and switch off the fire alarm(we have an optical one) before every show where haze/fog is used. There is a control box with a key that you can turn it off.


Have the local authorities approved doing this? It seems to be assuming a huge liability to do so without approval.


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## Les (Nov 29, 2008)

Wallab said:


> In our auditorium I always go and switch off the fire alarm(we have an optical one) before every show where haze/fog is used. There is a control box with a key that you can turn it off.




Yeah I agree with museav. People could die if there just so happened to be a real fire somewhere else at the same time.


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## ScottT (Nov 29, 2008)

Wallab said:


> In our auditorium I always go and switch off the fire alarm(we have an optical one) before every show where haze/fog is used. There is a control box with a key that you can turn it off.



Sounds like you would end up being personally liable if something happened. Make sure it's been approved in WRITING before EVERY show.

I think that there was a thread sometime ago about a techie being personally responsible for a death he had caused for something like that, and that he was serving jail time.

But my memory isn't what is used to be so maybe one of the more senior members will pitch in...


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## Sayen (Nov 30, 2008)

This is part of that "The Show Must Go On!" mindset which is deadly in theater - no theatrical effect is worth putting the lives of your audience, performers, or crew at risk, and especially not in an educational environment.


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## marshmolly123 (Mar 10, 2009)

At our HS we have to do something with the fire alarms whenever there's a big show. Turns out that, when the fire alarm system was updated two years ago, it was programmed so that even when we thought it was okay, we were just playing chicken on the railroad tracks. (I know "do something" is vague, but it's not my job, it's the TD's. I'm not entirely sure what it is, but I know we don't just disable it.)

Suffice to say that the fire curtain began to drop during one musical of ours and during a dance performance of another company. Not amusing. Let's just say the local fire department has learned to call ahead of time before coming over.

Fortunately, the system was fixed.


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## Dionysus (Mar 12, 2009)

I've had some negative experience with fire alarms in theatres. But now with my other vocation I actually install/maintain fire alarms periodically.

I have to agree with much which has been said in this thread.

Typically Heat and Rate of rise detectors are used in auditoriums (as long as the people who installed them know what they are doing and such). Simply because you really do NOT want a false alarm from effects. I've often seen the smoke-based detectors installed *outside* of the house/stage area.

I remember during a rehearsal in the local community theatre, snow was blowing inside the attic and settling in a couple places. This snow melted and dripped down a couple places, including directly into one of the heat detectors. It completely shorted it and set off the alarm. It is a single-stage system (alarm is immediate, there is no grace period for inspection and verification).
Someone noted a slight burning smell (turned to be someone's coat too near a heater) and so when the F.D. arrived I went around with them and did a search throughout. We found nothing.
So I figured out which circuit was giving the alarm, traced it, and found the shorted detector... So I had to remove the detector, re-arm the system and replace it the next day (when I could get my hands on a new one).

Not fun...

Many times I've disabled fire-alarm systems, but as an electrician, not a technician.

I also remember one time where an ASM went to buy oil for lanterns for use on stage in _The Tempest_. She got citronella oil instead of paraffin. Never told anyone that she filled them up, meanwhile asked what kind of oil we used. Just went to canadian tire and asked the guy there for the oil to put in the torches. lol. Took a little while before the fire alarm went off. the smell should of been warning enough to the high-school actors. But they just left them to continue burning...

I also remember once at college, in the second theatre (the black box) some people were working on some lighting projects with fog and haze. Turns out there were detectors in the ventilation in that area. Now they know better than to allow atmospheric effects in the blackbox theatre. Happily the other was designed with such effects in mind. It is perfectly safe to use them in the larger theatre. Hell we've made it so you couldn't see your hand infront of your face in there.

fun


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## kiwitechgirl (Mar 15, 2009)

We have smoke detectors in our theatre space, and it's further complicated by the fact that we're in a historic building so the rules and regulations are doubly strict. The system we have is that there's a timer in the control room which isolates all the detectors in the theatre space for half an hour, so when it clicks off the operator just winds it back and we get another half-hour. The detectors in all other areas of the building are not on the isolating circuit so the alarms function as normal. This kind of system is the norm here - although mostly you get more than half an hour, three hours is much more common, but we're limited through the historic status we have. It's a right pain during tech when you have the operator in the house, you have to have someone sitting there with a timer to jump up and reset it every 28 minutes. Better than not being able to isolate the alarms at all though! We do have to be a bit careful with haze escaping into backstage areas where the alarms are not isolated, but heavy curtains take care of that pretty effectively.


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## chriskreidler (Mar 16, 2009)

Blah067 said:


> I have a question:
> 
> In our theater, backstage left and right, we have a little glass box that says "break glass and pull in case of fire". But its not a pull-station, (theres those right next to it), and a cable is attached to it going up into the flys. What does this do?



It could be a smoke hatch release cable. Our theater has four hatches that open on the roof when the fire alarm goes off to let out the smoke. But I don't really know, that's just a guess.


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## Sony (Mar 17, 2009)

chriskreidler said:


> It could be a smoke hatch release cable. Our theater has four hatches that open on the roof when the fire alarm goes off to let out the smoke. But I don't really know, that's just a guess.



Smoke hatches don't usually have a pull station, however Fire Curtains do. 

I don't know how the smoke hatches at MVPAC are released, I think they are fuseable links but they are not activated by the fire alarm because they have to be manually closed from the outside by climbing on the roof of the flytower and being a high school there is a false fire alarm almost every week. Our smoke hatches are these huge spring loaded doors in the roof of the flytower that fly open very quickly when activated. One of them opened during a rainstorm one night a while ago and my boss came in the next day with the stage covered in water. It took three people to get it closed up and reset again because of how heavy they were and the force of the springs. 

Apparently fuseable links need to be replaced every 5 to 7 years because my boss had ours come down for no reason a couple years ago when the links failed randomly. We had J.R. Clancy come in and take a look at it and I guess the guys said that the links need to be replaced every so often.


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## SAWYeR (Mar 18, 2009)

Back when I was in high school, any time we wanted to use fog or haze for a show or event we would calll the school's engineers on radio and they'd shut the fire alarms off in our Auditorium. This also turned them off in the theatre across the hall...But since all our sensors were laser trips, we never ever chanced it. Clearing a 4,000 student high school in the middle of the day is NOT fun.


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## Sony (Mar 18, 2009)

SAWYeR said:


> Back when I was in high school, any time we wanted to use fog or haze for a show or event we would calll the school's engineers on radio and they'd shut the fire alarms off in our Auditorium. This also turned them off in the theatre across the hall...But since all our sensors were laser trips, we never ever chanced it. Clearing a 4,000 student high school in the middle of the day is NOT fun.



Clearing 4,000 people from a high school is MUCH better than having a real fire and then having hundreds of people DIE. Please look up "The Station Disaster" for an example. What you and your "school engineers" did is highly illegal and dangerous.


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## mrb (Mar 20, 2009)

Sony said:


> there are some really intelligent ones nowadays that can actually sense the ionization of air that happens just before a fire ignites...of course that would mean no more fire or pyrotechnics on stage ether. That and they are incredibly expensive...mostly used in Datacenters and Stuff like that.
> 
> > those are called VESDA (very early smoke detection apparatus) or something like that. They are THE WORST, even in datacenters. They work by pulling a continuous air sample through a system of tubes (looks like pvc pipe with holes in it) and into a sampling box where the air is passed through some sort of laser detector. Anything can set them off. Cutting metal with a grinder sets them off. Pulling a cable and disloging some dust sets them off. Eat too many tacos...well you get the point.


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## mrb (Mar 20, 2009)

ScottT said:


> Sounds like you would end up being personally liable if something happened. Make sure it's been approved in WRITING before EVERY show.
> 
> I think that there was a thread sometime ago about a techie being personally responsible for a death he had caused for something like that, and that he was serving jail time.
> 
> But my memory isn't what is used to be so maybe one of the more senior members will pitch in...



touching the fire alarm without approval from the FD or whoever has jurisdiction constitutes tampering, and if you tamper with a fire alarm and someone gets hurt, you will be in jail for a long, long, time.


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