Foggers, hazers, smoke alarms, and the fire department, oh my!

Andrius Simutis

Andrius Simutis

Veteran
I'm going to be shooting a music video this weekend and for part of it we really want that slight haze effect for the light beams to show. The only catch is that the venue we'll be shooting in has let us know that they will absolutely NOT allow a fog machine to be used. It turns out that they did a few years ago and it set off the smoke alarms that are connected to the rest of the complex which brought in the fire department and resulted in a fine for them.
They admit that their smoke detector is too sensitive, but they just can't risk bringing in the wrath of the fire department again.
Any ideas of alternative ways to create the light shafts that won't trigger a fire alarm?
 
Call the FD (non emergency number!) and tell them what you're doing. Since the venue is likely part of a larger building, the alarm system will have different zones. The FD can turn off your zone and stand by as fire-watch until you're done. You will have to pay an off-duty firefighter to do this, but it's better than a fine and alarms going off.
 
Do you need swirling smoke/dust or just the light shafts? I'm you can't do it practical you're probably limited to CGI for the former. Don't think it will help with shafts of light per se but with strong back lighting you'll be able to creatively flare, halate and blow the backgrounds with fog, mist, contrast, diffusion or strong frost filters.

Even if you can find something with particles that won't trigger the alarm they might not be willing to let you use it. You could maybe cover the sensors but will need permission from the owners and possibly their insurers and the fire department to do it. In a construction environment we have done this at work during an installation that generated a lot of dust causing similar problems to what you describe. Proceed carefully if you want to approach it this way, there are a lot of liability issues involved. We had to down tools for 2 weeks while the office people sorted it out after the alarm went off the first time so I'm guessing there's a lot to negotiate even though I wasn't directly involved.
 
Thanks for the advice. I did call into the fire dept yesterday and got bounced around six different people before leaving a message with (I hope) the right person. Since the shoot is this weekend, it might not be enough notice to have them involved anyhow…but gotta try, right?
I can do light shafts in after effects, and can add a bunch more lights and flares too. It's just a lot of work for something that normally would already be there with a minimum of fuss.
Has anyone been able to replicate the haze with another practical effect?
 
An oil cracker is a device that essentially atomizes cooking oil so that it hangs in the air. Great for making a thin haze that stays in the air much better than standard fog. But I would be concerned that it might be just as likely to set off the hair-trigger alarm.
 
There are different kinds of smoke alarms, ones that sense heat, ones that sense gas, and ones that sense particles. Particulate detectors can be set off by haze, fog, and dust. It would be helpful to know what kind of detectors your venue has.
 
If they previously set it off from a smoke/haze machine, it would be particles, not heat. (I don't believe any smoke detectors detect gas, I think there are specific gas detectors built in with them, but I could be wrong)
 
Problem solved! We switched to a different venue that has a fog machine already installed.
Thanks for the suggestions, happily we won't need to resort to any of them.
 
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