Low Lying Fog Effect without using Dry Ice or Fog Machine

[seanandkate]

Your artistic director is correct in his concerns for the use of dry ice. If you haven't got the airflow to get rid of water based fog, you certainly don't want to run the risk of exposing a captive audience to that volume of carbon dioxide. Plus actors would be at the risk of exposure standing in CO2 fog for 70 minutes. I think sk8tsdad is on the right track with a lighting driven solution.

[BDS0111]

Van has a good suggestion too, although it would be costly!

There are many ways to manipulate the air flow, you just have to experiment and see what works for you. Perhaps the fog wasn't working well before because the ideal fluid wasn't being used??

I guess I didn't see the post about the lighting...that is a good thought too! Great thought!! What is the lighting concept for the production like? You'd need something strong to punch through the other stage light maybe... Could be a great solution.

[gafftaper]

I seriously question the artistic choice of fog for 70 minutes straight. Not only is it a very difficult thing to do, I think the audience will get annoyed with it quickly and it will just be a distraction. This is theater right? There is a reason you've never seen this done before. Is this show about acting or about fog? Continuous fog is just going to be a distraction for the audience as it slowly gets more and more out of control. Use some dry ice fog to set the mood for 5 minutes then cut it and let the actors do their job. The purpose of theater tech is to create the world that the play exists in while staying out of the way of the audience's experience. Any time you do some sort of over the top effect like this you better have a REALLY good reason for it, because you run a high risk of annoying the audience.

Creating a lighting effect which could be dialed back as the setting is established is a great idea.

If you are stuck on fog you could try a chemical fogger with a chiller and LeMaitre's extra quick dissipating fog juice. Maybe it will dissipate fast enough to not block the audience's view.

What's your budget? The best option would be to create a 6" platform on top of the stage. Run duct work into it to let the fog out and then create a perimeter of ducting to suck the fog back out as it reaches the edge. This would be complicated, time consuming, and expensive to do right.

[Les]

Just for future reference, the directors were probably requesting a "low lying fog effect". Might help in future searches

[gafftaper]

Spelling fixed for future search purposes.

[ruinexplorer]

Well, if you are looking for long running fog, you should consider what is being used for themed environments, ultrasonic water mist foggers like this. However, this is opening a new set of dilemas. I used this type of systems in a museum that I was working in. Since you state that you have little air flow, this should look nice, problem being where to have the water and how to suitably move the fog. Ideally, you would want the mister to be directly under you perfomance area with a perforated deck to allow the mist to rise up. You would need to have your deck be topped with a non-slip surface since you would undoubtedly have condensation on the deck. The biggest concern with doing this is ensuring electical safety. When installing in the exhibits, we had the luxury of installing the proper GFCI protection as well as barriers to keep personnel and visitors from being near the water. So you would also need to use precautionary measures to prevent electrocution (very possible). I recommend that if this method were to be considered that a licensed electrician be available to provide you with the necessary GFCI protection.

[BillESC]

To accomplish what the director wants, here's how to do it.

First, install an 16 to 24 inch plexiglass trim to the stage. This will create the "pool" the chemical fog lives in.

Second, you will need to refridgerate the floor of the stage probably 10 degrees below the ambient temperature of the venue. You'll have to experiment to fine the minimum amount of cooling required to keep the fog from warming.

Third, duct the fog to the stage from a remote location.

Forth, remove warming fog by having a vacumn duct. (Input up stage right, vacumn out stage left.

[BillESC]

BTW, I'd suggest the actors wear heavier than usual socks.

[JChenault]

Originally Posted by seanandkate

Your artistic director is correct in his concerns for the use of dry ice. If you haven't got the airflow to get rid of water based fog, you certainly don't want to run the risk of exposing a captive audience to that volume of carbon dioxide. Plus actors would be at the risk of exposure standing in CO2 fog for 70 minutes. I think sk8tsdad is on the right track with a lighting driven solution.

I've heard this fear of CO2 with dry ice fog, but I have not seen any studies that show it to be a problem. It seems to me that it would take a LOT of dry ice to increase the level of CO2 in the air to toxic levels. Does anyone have any reputable studies that quantify the danger to actors, audience, or crew from extended exposure to a dry ice type of fog?

John

[gafftaper]

Here's a safety notice on City Theatrical's site from the compressed gas association. I'm yet to find a documented death. But there are plenty of warnings like that from fairly reliable and official looking places.