High Velocity Fan

[gherriott]

I am currently in the tech stage of a show (Bernarda Alba) which as part of the design has a traverse set with two huge doors on either end. One door is a large barn door with various smaller openings within each large door. One effect for the start of Act 3 involves me building up a large amount of smoke behind the doors with a Unique Viper Smoke machine and then using an RE - III DMX fan I blast the doors open with the smoke billowing out and an actor walks through the doors out the smoke. This making sense? Now I know the fan can blow the doors open, all be it rather gracefully rather than forcefully (which is a good thing!), but my question is, how do I risk assess this? My worst nightmare is there being some small object being dropped behind the fan or anything really that can accidentally be sucked up in the fan and propelled at a stupid force out towards the actor and audience. Has anyone done this sort of thing before, and if so do you have a risk assesment I could look at or could you point me in the right direction. Please don't just say it's too dangerous, don't do it etc.....as this doesn't really help me! If it is really too dangerous and there is no work around then pointers as to why this is so would be greatly received.

 

Many thanks.

 

Greg

[smalljoshua]

OK, risk: objects being sucked into fan and hitting actors, probability: low, precautions: keep everyone away from fan apart from actor making entrance & make sure area behind fan is clear from objects liable to be sucked up by the fan.

 

Hows that?

 

Josh

[lightsource]

how do I risk assess this?

 

Greg, as you already work in the theatre industry, I'll keep this simple.

 

Go back to the HSE basics :P

 

1: Identify the hazzards:

 

Strong wind, flying debris, doors being blown open.....you know the score.

 

2: Decide who might be harmed and how.....

 

Actors, staff....etc point 1 identifies how.

 

3: Evaluate the risks, and decide on precautions.

 

Go through them in a logical manner, ie injury to staff....

 

Other points:

 

Could you barrier off the fan to limit access, will there be a dedicated operator for the fan, who has a good view...

Is the set construction strong enough to withstand the wind

 

Edit to add...from the RE III operators manual....

 

.....Suction at the fan inlet is extremley strong at full power, loose particles, dirt etc can be ingested, and expelled at high velocity.....

 

Just thinking - dust, dirt, eyes.

[gherriott]

how do I risk assess this?

 

Greg, as you already work in the theatre industry, I'll keep this simple.

 

Go back to the HSE basics :P

 

1: Identify the hazzards:

 

Strong wind, flying debris, doors being blown open.....you know the score.

 

2: Decide who might be harmed and how.....

 

Actors, staff....etc

 

3: Evaluate the risks, and decide on precautions.

 

Go through them in a logical manner, ie injury to staff....

 

Other points:

 

Could you barrier off the fan to limit access, will there be a dedicated operator for the fan, who has a good view...

Is the set construction strong enough to withstand the wind

 

 

Thanks for that. I'm aware of how to construct the risk assessment, but it is more the oversight of a potential risk that I am worried about. Just wondering if there are any hidden risks that you might know of having maybe done something like this before. The fan is being run via DMX, with myself being the operator. I do not have line of sight of the fan. There will be an ASM next to it should something go wrong and it have to be isolated from the power supply. So far I have accounted for small objects being sucked into it, loose objects on the actor's costume being blown off and the set durability. To reduce the risks of these I have put in the report that the stage areas should be swept thoroughly before each show (no interval). The costume department have been informed about not having any loose objects on the costume, ie no sequins etc and the set is certainly sturdy enough to widthstand the force. Are there any other concerns that I might have missed, especially with it being a traverse set?

 

Thanks.

[J Pearce]

Consider having the fan on a deadmans handle (or several) so that it cannot turn on (DMX isn't error checked!) unless the button/handle is held in.

 

Perhaps the area ought to be vacuumed as well as/instead of being swept to reduce dust and grit.

 

Think about caging the fan front and back in order to enforce a minimum distance from the fan at all times.

 

Check all set for loose items, and think about bolting any items to control when items that need to be loose for a scene can be loose.

[lightsource]

I knew you would be capable of doing a RA, hence why I kept it simple. I'm more live music based, so can't really comment on the Traverse sets etc...

 

I do think that the ability of the set being able to withstand the 25+ mph gusts of wind might be worth looking into. Will you be able to do some tests before the show?

 

Just a thougt, but as you won't have line-of-sight when operating the fan, could you not give the op job to the ASM, who will be there.

[J Pearce]

Another thought, as traverse brings the audience closer to the effect consider the possibility of loose items within the audience. It might not be an issue depending on how wide the wind 'beam' is.

 

Following on from that, mount the fan firmly so that its aim cannot be knocked or shake loose.

[gherriott]

I knew you would be capable of doing a RA, hence why I kept it simple. I'm more live music based, so can't really comment on the Traverse sets etc...

 

I do think that the ability of the set being able to withstand the 25+ mph gusts of wind might be worth looking into. Will you be able to do some tests before the show?

 

Just a thougt, but as you won't have line-of-sight when operating the fan, could you not give the op job to the ASM, who will be there.

 

Sorry that was not meant to be a snappy comment Lightsource! - I appreciate the comment. With regards to the ASM operating it, there is no remote for it, so they would be in direct view of the audience if there were to be next to it to press the button! I have trialed it a few times and the set is still standing...so hopefully it will be strong enough! Thanks everyone for the comments. I will add that it should be vacuumed too as this will eliminate grit and dust particals too.

[J Pearce]

Look at building a deadmans handle.

 

Just needs to be a push to make switch for mains. Could be done with an el cheapo switch and relay - though use a normally open relay obviously.

 

Just means the fan cannot run unless the ASM is there to watch it and that if it all goes wrong and the ASM legs it in fear of his/her life the fan will stop.

[gherriott]

Look at building a deadmans handle.

 

Just needs to be a push to make switch for mains. Could be done with an el cheapo switch and relay - though use a normally open relay obviously.

 

Just means the fan cannot run unless the ASM is there to watch it and that if it all goes wrong and the ASM legs it in fear of his/her life the fan will stop.

 

I shall definitely look into that, especially with me not having line of sight of the fan either. Thanks for that. :P

[lightsource]

Sorry that was not meant to be a snappy comment Lightsource! - I appreciate the comment. With regards to the ASM operating it, there is no remote for it, so they would be in direct view of the audience if there were to be next to it to press the button! I have trialed it a few times and the set is still standing...so hopefully it will be strong enough! Thanks everyone for the comments. I will add that it should be vacuumed too as this will eliminate grit and dust particals too.

 

Naaah mate, the mods will tell you what I'm like when I'm snappy :P I just appreciated the fact you knew most of what I was going to say.

 

Just one point I've noted though.... you said there's no remote........but it's controlled by DMX, could you not give the ASM their own DMX controller?

[Russ83]

Just a couple of thoughts to minimise the risks:

 

Would it be possible to put a second fan at the other door to assist with the initial draft and to keep the smoke flowing over the stage area and not just gassing the audience by the entrance door?

 

Is there a need to run the fan continuously at high velocity or can it be turned down or off once the door has opened?

 

Any chance of human assistance (hidden from the audience) with opening the doors and just use the fan on low to move the smoke?

[dbuckley]

Hmmmmm..... I know nothing of this show or the aforementioned fan, but have been on the Twister theme park ride which has several very large very powerful fans just inches from the audience and it blasts the heck out of people many times a day, so it is clearly possible to do this to the satisfaction of the litigious concious lawyers.

[Jivemaster]

Try the fan and view it from a fair distance (PPE) -See what it is likely to pick up and see how to prevent that. The area local to the fan intake to be swept of anything that the fan can pick up. See how far away a matchbox can be or a small spanner. Assume that all books and loose papers will flutter and post-it notes may flutter or fly.

 

Raising the fan off the floor will help if the whole fan is safe from flying!

 

Consider assisting the doors with weights and pulleys, bungy/shock chord etc to reduce the need for fan power.

[ImagineerTom]

You are approaching this the wrong way - use springs (as others have mentioned) to create the door bursting open, you can then use a suprisingly small fan behind it to create the billowing smoke; a little 12" desk fan will shift a suprising volume of air and it's volume that you want to achieve.

 

Twister uses high volume low pressure fans (like airdancers or bouncy-castles) as creating indoor tornado's is all about the movement of air and the pressure variations this creates rather than specifically trying to create pressure.

 

t