# smoke machines and H&S



## rgsw (Sep 7, 2004)

i am currently debating with our health and safety officer in the uk about using smoke machines as they may set off the smoke detectors.

How does anyone get around this?

also everyones lovely friend H&S is now stopping us from using hand saws - how do anyone cope with this bearing in mind our stage crew is aged 16. We have the same situation with ladders,scaffolding,mawp's etc...

any advice?


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## avkid (Sep 7, 2004)

if i am right i don't think that smoke machines should set off alarms unless you are not careful!


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## avkid (Sep 7, 2004)

if i am right i don't think that smoke machines should set off alarms unless you are not careful!


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## jorno67 (Sep 7, 2004)

First find out if your detectors are heat or particle, if they are heat detectors you're free to smoke away. If they are particle then you need to find out if they are located out in the open or are they inside the hvac ducts, if they are in the hvac ducts you are free to fog away. BUT, if they are out in the open you will need to meet with your local fire chief and discuss possibly turning off zones or even bagging the detector for the duration of the performance. I once worked it out that I called the fire chief when I turned off the zones and again when I turned them back on, before and after every performance using fog. And if none of that works out...too bad, no smoke/fog for you. Of course this all happened in the states, I have no Idea about the UK.


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## Foxinabox10 (Sep 7, 2004)

You can also use a low-line fog machine, which actually cools the fog with ice to keep it low to the ground, allowing you to fog all you want. Try a hazer too.


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## Mayhem (Sep 7, 2004)

Foxinabox10 said:


> You can also use a low-line fog machine, which actually cools the fog with ice to keep it low to the ground, allowing you to fog all you want. Try a hazer too.



This does work well, but once the smoke warms up or is stirred up by performers, you have the same issues as with a regular smoke machine. In most applications, you actually want a small amount of smoke to be present for most of the time to accentuate the lighting. For me, this is particularly the case when using intels.

As a mobile DJ, I always enquire as to the presence of smoke detectors and whether they can be isolated or not. I then ask for this in writing, just to cover me in the case of an alarm being set off by me.

Some venues will simply say NO to smoke. In particular, those where there are elevators, as if any smoke does find its way into the elevator shaft the whole building will have to be (in theory) evacuated and the fire department called out to inspect. Now – should the fire department have to come out and conduct an inspection for a false alarm. It is not free (in Australia) and if I have been found to be at fault, the cost could be passed on to me to foot the bill.

Only once has this happened and it was in a venue in which I had asked if the round white sensor in the middle of the roof with a pretty flashing LED was a smoke detector, and if so, could it be isolated for the gig. I was reassured that it was in fact a glass breakage detector and that I had no problems with using smoke. I asked that the person check that this was the case (as it looked like a smoke detector to me) and get back to me in writing. He did, and the letter stated that the detector in question was not a smoke detector and that the venue did not have any smoke detectors that were monitored.

Well – sure enough, a couple of hours into the gig a familiar high pitched screaming alarm went off :roll:


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## rgsw (Sep 8, 2004)

thanks very much for all this as i can now tackle our officer with some questions and how other theatres cope


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## Robert (Sep 22, 2004)

Hey, smoke detectors detect smoke - no matter how it is manufactured. Detectors may be in the Green Room, Lobby, Auditorium, Backstage and in the Air Ducts. Use enough smoke and they will be set off. I have used fast dissapating smoke in both low level and diffusion settings. Low level uses a refrigerant to chill the smoke and keep it low. As it warms up it dissapates. Using the fast solution keeps it from lingering and has worked for me in several situations. I ask for a test of the smoke system before the audience enters. Usually one of the physical plant electricians shows up with a radio to communicate to the control board. I try several settings and locations to make sure. I even have somebody else dance (I'm a techie, not a dancer)and mimic the actions of the cast to ensure I have covered all the bases. One important issue is to make sure the auditorium air units are running. If nobody is in the auditorium, the air units may not be running. Once an audience enters, you will have a new air flow so this will bring the detectors in the AC unit into play. 
I shut down an entire hotel once after being told the detectors were isolated. Elevators, escalators and the such. The fire department showed up as well. Always ask twice, then ask again. The room manager took the blame for that one.


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## zackw250 (Sep 23, 2004)

We have smoke detecters that are infra-red beams that are shot across the top part of our auditorium. Our HVAC unit is usually always on (but not always cooling or heating) so we usually dont' have problems with Haze getting very high up cause it gets blown down by the vents and sucked out under our stage. But the HVAC system has 10 minute turnaround. What this means is when the system detects that the tempature has risen above the desired setting, it shuts down completely (dampers close, no air movement at all) for 10 minutes, before restarting with either the cooling or heating unit active. During this time haze WILL and DOES rise and setup the beam smoke detecters. Our HVAC system also detects pressure differences in the room. So during performances, we always leave one door in the back open so the pressure is never equalized which causes the system to stay ON and bypasses the 10minute turnaround time.


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## Peter (Oct 2, 2004)

Last year my school moved back into a newly renovated building (with a brand new Auditorium  ) and of course the principal wanted an assembly. I got in to the building with about 20 minutes to learn the new equipment, before 400+ students filed in. As they all walked in and sat down I could see the problem immediatly, dust was rising in huge plumes from the upholsterd seats!!! About 10 minutes into the assembly enough dust made it into the vents to trip the optical detectors, setting off the firealarms! The principal quickly figured out what was happening, and told everyone not to evacuate (not sure if that was leagal or not, but it was him not me!). 

The lesson learned, keep a clean venue and dont underestimate the sensativity of optical smoke dectors!


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