Smoke Machine

[robthelightman]

Will a smoke machine set off a school smoke alarm???

 

 

Regards

Rob

[gareth]

Depends on a lot of factors - mainly the type of smoke alarm. The airflow and ventilation in the theatre also plays a part, and to a lesser extent the type of smoke machine might also have a bearing on it.

 

It's always safest, though, to try to arrange for the fire alarm zones covering the theatre to be isolated for the duration of smoke use.

[TallPaul]

Depends on the type and location of sensors, and the type of machine/fluid. Often in theatres, detectors that use both temperature and particle detection are used, which can allow for one type of detection to be isolated during performances and still provide detection. Check what kind of system is installed with the relevant person.

 

Paul

[Modge]

If it's smoke rather than heat detectors there's a good chance of setting them off (speaking from bitter experience - fortunately in our place they go to pre-alarm before they go off - you have 5 minutes to sort it - stage fans were invovled at this point). Heat sensors should you have the good luck of the place being fitted with them will be fine. If your in a school you'll probable need to talk to the caretaker or similar and convince them that they want to isolate which ever zone the hall is on.

[the kid]

Admitadaly we have never had this problem. We have never had detectors only ever the glass break points. At college we have them and also some covers but we cant use them becasue there out of reach of the tallie.

[Freddie]

Welcome to BR! (Do I smell the smell of someone younger than me? I'm Yr9)

Yes, probably will set off detectors. Even after arranging the Fire Alarm to be muted or whatever, it's still worth telling the caretakers/office/whoever's in charge of the fire-alarm control panel a few mins before the effect through internal phones/radios/runner. You'd be amazed at the number of times the office staff have changed over at our school, not told each other about the smoke machine, seen a red light on the panel and run down to the theatre in a state of panic...

[Brian]

As a bit of background....

 

There are 4 types of fire alarm in common use...

 

1. Ionization detectors - as used in typical domestic smoke alarms, usually way too sensitive for use in commercial enviroments. Work by the interaction of particles in the air interacting with a radioactive source and detector.

 

2. Light Scattering detectors - a source of light shines at a light detector but there is a barrier in the way so normally no light is detected. When smoke is present the light scatters off the smoke particles and is picked up by the detector.

 

3. Heat detectors - trip to alarm at a preset temperature.

 

4. Rate of heat rise detectors - react to a fast rising temperature not the absolute temperature.

 

In many situations it's a good idea to have two different types of detector, both of which have to say 'fire' before an alarm goes off, as it reduces the chance of a false alarm. In this situation it's usual to have an indication that one detector has tripped so that you can investigate; often called a 'double-knock' system.

[robthelightman]

Thanks for your help everyone

 

I will ask the caretaker at school if he can isolate the smoke detector

[AC03]

just a little thing I learned, at my school when my technical director asked the caretaker to isolate the alarms, we got told that it would be against fire saftey regulations..., is that right ?

[vinny baby]

just a little thing I learned, at my school when my technical director asked the caretaker to isolate the alarms, we got told that it would be against fire saftey regulations..., is that right ?

 

yes

[Light Console]

Yes well, I can now speak from experiance! Picture the scene, the end of a conference, 40 odd people on the dancefloor, and a ZR22 going at full pelt for 30 seconds once every five mins on a chase in the desk. Eventually there was lots of smoke and the lighting was looking fab. Although the room was full of smoke, we had isolated the detectors in the venue. 10 mins later the alarms went off, the PA went off, and every one was looking at me! Within seconds the security people of the site were on hand. We had triggered alarms down the corridor and into an arcade. We can only guess they had a two stage alarm and were already on the way by the time we set off another in the arcade.

I will never use too much smoke again!

Some schools have a timer overide, a bit like on old washing machines. Turns off the alarms in a zone for a set time, then reinstates them automatically.

 

HTH,

Rob, now back from his trip to sunny Blackpool for the last month......

[bruce]

....... asked the caretaker to isolate the alarms, we got told that it would be against fire saftey regulations..., is that right ?

 

yes

<{POST_SNAPBACK}>

 

I would have guessed that the answer would have depended on a number of factors - the design of the alarm system, the types of detectors, whether all or just one type were isolated, whether the alarm was completely disabled or just put into "silent alert" mode, whether we're talking about statutory regulations or local ones etc etc etc...

 

If the local/site fire regulations say "thou shalt not isolate the alarms", then doing so is by definition against "the regulations"....

[sam.henderson]

Some schools have a timer overide, a bit like on old washing machines. Turns off the alarms in a zone for a set time, then reinstates them automatically.

 

The Fire Alarm in a venue I use often just beeps very loudly until you turn all the areas back on. Not a problem really as the box is out of the way. I have seen quite a few systems that work like this!

 

You should make sure however when you are disabling areas you are only disabling detectors not the Break Glass type panels around the venue!

[danburns]

Unfortunately our venue has an AFA front of house, covering bar, rehearsal and storage next door. Backstage is covered by a series of domestic smoke alarms, including one in the flys above the stage. I have managed to set it off on more than one occasion, luckily all outside of productions. We have now fitted the battery in a remote box near the SM, complete with keyswitch isolation for our next show due to lots of smoke being used.

 

As mentioned in general chat before, another SM set off the backstage system when the performers held all the stage doors open...just 15 minutes after the "official" fire drill...oh the fun!

 

 

Going back to the OP, we have no problems in our school hall during productions - the french department once evacuated the place due to burnt toast though! We do however warn our site manager, the senior caretaker during the run up to the show, as well as reminding the on duty caretaker on the night that if the alarm goes off in the hall zone thats probably what the problem is - although they reserve the right to evacuate the building even if it's obviously a false alarm - our policy is as long as the alarm is ringing, no-one is pemitted to remain in the building. They don't isolate the zone either.

 

Dan