HI GUYS

The next show into our theatre (AMDRAM) have hired in SLX dry ice machine. Unfortunately they did not wish to take advise about using Low smoke for a hassle free we have a 10 metre wide stage and 3 metre deep pit at the front. Can't seem to find any info on the safe use of dry ice in an entertainment venue. do I need to insist on CO2 monitors in the pit. how much dry ice becomes dangerous. SHOULD I BE WORRIED

if some one can point me in the right direction it will be a great help


thanks

James

Yes, there is certainly a risk - dry ice expands to many times its volume when it turns to gas, and as it is chilled, it will be low-lying, so it will tend to flow into the pit. Unless this has forced ventilation, there is definitely a hazard here - although CO2 is non-toxic, it is an asphyxiant, so you could possibly wipe out your orchestra!

Some information & guidance here: HSE Smoke and vapour effects used in entertainment

Is it actual dry ice (I.e. Carbon Dioxide vapour) or is it lowsmoke from a fluid solution? Assuming that it is actual CO2 that you are using then yes definately you MUST have proper and adequate ventilation. CO2 in its frozen form is chilled to a temperature of minus 78.6 degrees Centigrade and can cause instant skin burns if handled without using gloves - I know, I picked up a box once where the gloves I were using had a small hole in them and after about 10 seconds I had a huge and painful blister where my skin accidentally caught the outside.

As the cold pellets are added to the hot water they produce the vapour which we all know and love as the low lying smoke effect. Because the CO2 is heavier than air, it stays low to the ground and can seep into all areas including over the edge of a stage and into the pit. If a member of your orchestra happens to breathe some of the fumes then at best they may keel over and be taken to hospital in an ambulance where they would hopefully recover later - or at worst they will die. I don't want to scare you into not using a fantastic effect but you do need to be aware of the dangers and seek advice on how to use the machine(s) properly, as well as risk assess where the smoke is likely to travel.

Many venues are able to still use actual CO2 by ventilating the front of the stage areas so that nothing seepes into the pit. If you are able to do the same and satisfy yourself (and others) that the effect you want will stay on the stage and go no-where else then you should be fine.

It's the same usual rule that you get with Pyro's, if in doubt, leave it out.

Hope that helps.

David.

Never mind the co2 dangers

http://www.chinesedepartmentstore.com.cn/o...roducts_id/2196

from our chinese friends - ce sticker an extra 25cents

Sam

CO2 as in the atmospheric gas and the one used in carbonated drinks not XyklonB

The vapour you see is NOT DRY ICE, its water vapour chilled out of the air by the sublimating dry ice, orchestras like to burst into fits of theatrical coughing at first sight of the vapour.

They are however unliable to expire, dry ice expands to 954 times its solid volume if remember correctly, guessing there is a physics graduate just waiting to correct that.

Take the volume of your stage and pit and take a guess at how much dry ice hyou would need to completey displace all the oxygen, without draughts , leaks, doors and HVAC...

It`s a risk but its a much exaggerated one, real roblem is keeping the damn effect running long enough in the right place.

Storage, do not use a working fridge, dry ice is a lot colder and will kill it, an old fridge as insulated box might help.

Handling, met a person who could only count to 4 on one hand after trying to break blocs with a stageweight, use gloves, eye protection and lots of respect.

I'll echo the above.

Whilst CO2 is NOT to be underestimated for just the reasons given, it's also OVER estimated for the supposed 'deadly' effects on those exposed to it.
For example, the show I'm working at the moment, act 2 opens with a large stage full of CO2 fog mixed with smoke from smoke machines (dual effect, the two aren't literally combined). Hidden under the level of the fog - from 2 Pea Soupers - are 2 or 3 dancers dressed as rats. They're quite comfortable in the fog, and after 6 shows (so far) we haven't lost one yet!
And the fog rolls off into the orchestra pit containing a fair sized group of musicians who play constantly throughout - I suspect (haven't checked, so can't say for certain at this point) that they have fans blowing the fog away from them and under the stage void (else they'd rather struggle to see the black dots on the pages!).

So the message is still pretty basic - CO2 is definitely something to treat with extreme care at the 'input' end, but whilst care is still necessary when it becomes fog, it's NOT as dangerous as some might have you think.

But at the end of the day, it's YOUR risk assessment that needs to take everything into account.

It's just slightly worrying that you don't seem sure exactly how many are left!

Buy a canary?

At levels above 5%, concentration CO2 is directly toxic ie 50,000ppm symptoms of high or prolonged exposure to carbon dioxide include headache, increased heart rate, dizziness, fatigue, rapid breathing, visual and hearing dysfunctions. Exposure to higher levels may cause unconsciousness or death within minutes of exposure.

5.4l of atmospheric co2 is released from a gram of CO2 dry ice so 10 kilo's releases 54000l of gas so unless you can dilute it into 1080000l of fresh air - you could have a problem (38139 cubic feet)

http://antoine.frostburg.edu/chem/senese/1...m-dry-ice.shtml

We did the maths for this a while ago - lost the will to live and hoped no one would ever ask - so far so good.

In actuality 3% for 15 min is the max recommended exposure in most OSHA environments

Sam

In actuality all gasses, even oxygen are fatal in large concentrations but most, even the nastier ones have an acceptable tolerance, Zyclon B, referred to here is relatively harmless if used in accordance with it's original intention (as opposed to how it was used by the Nazis) as an insecticide even though it is Hydrogen Cyanide (the US government used it as a de-lousing agent in prisons, it's still made by Draslovka Kolín a.s. and widely used for fumigating greenhouses!) Problem comes if the concentrations of the gas, whether it be Hydrogen Cyanide or CO2 becomes past the limit a living body can tolerate. the kind of benefit to CO2 is that it causes a response of gasping for breath, which usually warns of a need to get to air (it's close relative carbon monoxide does not)

That pit is bigger than the ops stage! Its about 15m wide by 10m and 4m deep. It also has Co2 moniters in there. Im amazed they let the rats "hide" under there for that legnth of time! but then they have done it for 20 years so it must be safe!.