Stopping a show

[gafftaper]

Fascinating. Probably 99.9% of my experience is in educational theaters, and I've worked in quite a few. Every single one that I have ever worked in had a fire alarm that rings with the whole building and no sort of automated life safety system. Even in at the two schools that built new theaters in 2008 and 2009. I'm wondering if the state of Washington ignores these particular codes or just what the deal is. Like I said Brad I'm not trying to argue with you, it's just that what you are talking about is so different from anything I've ever seen up here.

[museav]

Fascinating. Probably 99.9% of my experience is in educational theaters, and I've worked in quite a few. Every single one that I have ever worked in had a fire alarm that rings with the whole building and no sort of automated life safety system. Even in at the two schools that built new theaters in 2008 and 2009. I'm wondering if the state of Washington ignores these particular codes or just what the deal is. Like I said Brad I'm not trying to argue with you, it's just that what you are talking about is so different from anything I've ever seen up here.

No argument either way, in fact I'm very interested to hear any details regarding where someone had an AHJ approve their using the house audio system and how they addressed some of the related concerns.


I'm getting into territory outside my expertise but my understanding is that assembly spaces typically require either audible alarms (Code 3, slow whoop, etc.) or an Emergency Voice/Alarm Communication (EVAC) system that reproduces recorded messages as well as audible alarms. Certain conditions related to occupancy, height, etc. may require an EVAC system. This may explain why some people encounter such systems and others do not.

If your life safety system includes audible alarms or a voice evac system, then in my experience the AHJ may require muting or disabling the house sound system when a life safety alarm occurs in order to prevent the house system from potentially interfering with or reducing the effectiveness of the life safety systems.

Since EVAC systems have to incorporate live announcement ability, if you have an EVAC system then using that would seem the preferred option for making any announcements. You theoretically could use a house sound system as an EVAC system, however I believe that it would have meet all of the related requirements for that use (monitored, on emergency power, required levels and intelligibility and so on) and be tested and approved for the use, something that would apply to very few systems not designed specifically for that purpose.

An example of why a dedicated system is usually desired is that one would want to know that the announce microphone is always 'live' and that there is as small a chance as possible that it may have been unplugged, muted, repatched (probably even more of an issue with virtual patching in digital consoles), had the gain turned down, is not routed to the right outputs and so on. If you were to use the house system you would want some way to minimize all of those possibilities and to assure as much as practical that if you had to use the announce microphone in an emergency it would work as intended. And that might entail something like the announce microphone going direct to an input on the system processor rather than to the mixing console with a contact closure from the life safety system causing the processor to enable the announce input and mute all other inputs.

So the only way I see using a typical house system for announcements during a life safety event that seems to fit into the NFPA scheme would be as a supplemental system to the life safety systems. In other words, it may be used to provide additional information as long as it does not interfere with or negatively impact the life safety system alarms or annunciations. And that being allowed or desired, and if so any conditions or limitations involved, is something you would want to verify with your insurer, AHJ, etc.

But this is just all my interpretation based on my experiences and what others have told me, I welcome any related information or insights that anyone has to offer.

[urban79]

In our case, the fire alarm actually disables power to the speaker/amps... or at least should - I haven't actually had the system in operation yet. The one problem I find with all of this is that while a student audience will naturally obey the fire alarm, adults seem not to. We drill students so much with fire alarms that it is simply ingrained in them, but once out of school, very few people actually deal with a fire alarm going off. That is where confusion comes in, and several times I have had audiences simply stay in their seats for minutes while the alarm is going off...

Chris

[StewTech]

As MuseAV points out, that sounds like a great way to get roasted in a plume of hot toxic gasses. Smoke Vents are NOT the way to escape a fire.

No, in case of fire they would climb down to the midrail, and down the ladder. HOWEVER, in case of a Zombie Apocalypse, they could escape via the smoke vents; there is no fire in the theatre when the zombies invade.