Some nooby dimmer questions.

[Les]

I only thought it might control the theatres cooling because say the room is pitch black and silent, dimmer rack is off and ac is off. If I turn on the houselights, first the theatres air conditioned roars to life, then the dimmers fans turn on then the lights turn on. Its always freezing in the theatre because if the dimmers are in use the AC is on and for 40 mintues after the dimmers are off.

That is about the strangest thing I have ever heard of. Not quite, but about. Air conditioning will of course be activated when the room reaches a certain temperature (maybe an increase of heat due to lights) but I have never heard of an air conditioning system being activated by a lighting system. New acronym: DMXHVAC.

It is highly likely that the dimmer room's AC system is indirectly activated by turning on the lights. It should remain steady at a pretty cool temperature, but I wouldn't be surprised if it is activated by the heat generated by the dimmers. As far as the auditorium's system, sounds highly unlikely to me. There's got to be something else going on.

[cprted]

Okay, I will see if there is any empty modules, and as for the voltage, I would only assume it is in the manual for the rack I posted in my last post.

You're looking for WATTS, not volts. 1.2kW, 2.4kW, etc.

[MillburyAuditorium]

Les,

Maybe it isn't always on, but like 80% of the time, stage lights are on, so is the cooling system. I don't know really why, but its just to maximize safety I suppose. Being in a smaller space, the lights a VERY close to the curtains and once the cooling system had a little glitch and did not turn on, and we had to take an unexpected intermission and turn of the lights and open all the doors it was getting way way to hot to be safe. I'll take a look to see if there us some kind of wiring mess up but I think there isn't.
(The dimmer room is on the SR wing, and so is the air conditioning unit X_X hanging right above SR wing. But saprisingly, the ac unit because a very powerful one, isnt the thing makign most noise, its the dimmer racks cooling fans, those thigns are spinning peeeeerrrty fast, we made somethign to put over it without loosing much airflow and it cuts down the noise a lot. Without it all you can hear is a humming.

Anyways, I think its always on just to be safe, better have snow falling then a fire right?

[MillburyAuditorium]

-off topic-
I want one of those moving head fog machines :D SO cool.... But we would be lucky to get any commercial hazer xD
[media]http://livedesignonline.com/gear/ACCU-FOG-1000.jpg[/media]

-On topic-

Yeah, sorry cprted, Was just looking for a electricity value.

[Clifford]

Anyways, I think its always on just to be safe, better have snow falling then a fire right?

Not if you're trying to light a fire to stay alive in the snow.

Watts is the easiest thing to look for. However your modules may not be labeled with their wattage. The breakers, however, will state their amperage. If the wattage isn't labeled, multiply the voltage by the amperage on the breakers. I assume you're running 120V if you're in the US. So if your breakers all said 20A, 120V * 20A = 2,400W, or 2.4kW.

[Lightingguy32]

most dimmers of the type described in this thread have a label near the status indicator lights. The number corresponds to a current (such as 10, 15, or 20) and the wattage is determined roughly by multiplying the labeled current by 120(volts).

[Les]

Hate to say it but if your AC is the only thing keeping your softgoods from bursting into flames, your instruments are way too close.

Also, I am skeptical about this cover over your dimmers. I know noise is an issue, but any blocked airflow is too much. Not that I haven't done similar things in the past, but I would take a hard look at whether or not this cover is causing a potential fire hazard.

[renegadeblack]

Not if you're trying to light a fire to stay alive in the snow.

Watts is the easiest thing to look for. However your modules may not be labeled with their wattage. The breakers, however, will state their amperage. If the wattage isn't labeled, multiply the voltage by the amperage on the breakers. I assume you're running 120V if you're in the US. So if your breakers all said 20A, 120V * 20A = 2,400W, or 2.4kW.

I believe that the only module offered is 2.4 kW.

Also, pardon the brief hijack:
On my rack, its labelled on the left side and right in the middle, theres an airflow module that has B0 where theres an airflow module. I believe that there is one that is mandatory in the middle.

[derekleffew]

...I jsut realise,d we dont use twist-lock wires, all our lights have those big ectangle ones, Don't know the name. ...

Stage Pin Connector.

[MillburyAuditorium]

Clifford, Not 100%, but very sure that they are 2.4, someone else here said they have the same rack, it comes with the dimmers pre-installed, so guessing its the same, I believe it was you renegadeblack?





Les,
Well, if there was no AC no the curtains wouldn't go up in flames, but they are a little closer then I have seen the in most places, so the AC just helps to make sure that things like that don't happen.
Curtains of course are flame retardent and I would never put them so close they would catch the curtains on fire.
And for the cover, any intake reduction I think is substituted by it being pretty chilly on stage in the first place, and like I said, it doesn't alter airflow hardly any, All it is is a wooden box with no top and bottom, with just one of those black plastic screens on the top, so it sits right on top of the fan still allowing air to enter the unit. This reduces the noise a LOT because instead of the noise spreading in all directions, mostly left toward the stage, the noise bounces off the wood and travels straight up into the ceiling. It was designed by me and the man working the theatre before I came along, hes some what of a pro, hes into sound engineering, used to be all theatre.


Renegadeblack, yeah, you were the one who said you had the Colortran i92 right?



drereklefew,
Yup thats it :D

[shiben]

If your airflow is blocked, you can have so many issues. We actually had our CD-80 rack shut down because it was too hot, some dude from the cleaning crew put some tables blocking the air intake, and the heat sensor tripped during a very high profile show. So if for no other reason, move whatever it is blocking the airflow because your show is then in danger, also you have a fire hazard, and its bad for the dimmers, etc. Just bad all around. And if your lights are close enough for burning any soft goods, why? That is way too close. Probably looks silly too, I imagine that if a source 4 is too close to a teaser it might bleed thru, especially if its old (the teaser). Anyhow, thats an odd system, and i like the DMX-HVAC

[Clifford]

Clifford, Not 100%, but very sure that they are 2.4, someone else here said they have the same rack, it comes with the dimmers pre-installed, so guessing its the same, I believe it was you renegadeblack?

While we could assume, logically, that you're using 2.4kW units, you really need to know what you have. From what I could find on Leviton's website, the iSeries E can be equipped with dual 1.8kW modules, dual 2.4kW modules, single 6.0kW modules (50A), and 15A or 20A relays (non-dim modules that are on or off).

Again, most likely you're using 2.4kW units, but you may find that you have a few 1.8kW units, maybe even a few relays. When you check your rack, look at every module, not just one.

[gafftaper]

Dimmer Wattage: Look closely at the circuit breakers. They should have a number on them. 20amps= 2.4k watts 10amps= 1.2k watts

The Accu Fog: It's been a source of a lot of laughter around here. Fog generally spreads EVERYWHERE. You don't need to be able to point it at strategic locations that are constantly changing. It would look kind of cool in a small club falling down on you... if chemical fog actually fell like dry ice fog.

Fire Retardant and Curtains: How old are your curtains? Have they had their fire retardant actually tested in the last 10 years? They are treated yes, but it degrades over time. Most schools put in curtains and figure they are safe forever but that just isn't true. My MINIMUM testing schedule, you should have your fire retardancy tested before the curtains reach 10 years of age, then again every 3-5 years. If they ever get wet you need to have them retested immediately. I know lots of schools that have 20+ year old curtains that have never been tested. They think are fire retardant and safe... but you just never know. Here's something you can do right now. Take a close look at the curtains, do you see any weird discoloration in them? Imagine if you took a shirt and washed it in a lot of soap and without rinsing the soap out you left it in the sun to dry, you would see this weird residue sort of swirled into the shirt. That's what you are looking for. That's a visual sign that your fire retardant is failing. On the other hand not seeing any visual signs of failure doesn't mean the curtains are safe. You need to have them tested to know they are safe.

[MillburyAuditorium]

Shiben,
As I said, we have made sure that our little box does not alter airflow at all. It is simply a square box with no top of bottom sitting on top of the rack, so it has no bottom so the fan is still exposed and is sucking in air, the air is just coming from more upward then from right next to it.

Clifford,
I will check next time I am at the school. But being just a student, I cant just walk in during the summer unless its something really important for the theatre.


Gafftaper,

Yeah I kind of figured that about the accu fog thing xD But it looks kinda cool : )
The curtains are original from the time the theatre was built, I do beleive they have been tested, but I dont really know, thats more up to maintenance, but I will talk about the curtains with the guy we have comming in, being the same person who was here when they were installed.
As for dis-coloration I have not seen any, I will look closly for them though when I am there.

The lights arent so close that they will burn the curtains, I just said that because, if htere is no AC, then curtains or not its going to get pretty dang hot in there, especially on stage. Im not sure how much heat the curtains can take without burning, And so I will keep in mind the curtains when we are re-aranging hte lights.

[gafftaper]

Long ago... when I didn't know much... I was working in a theater that had the dimmer rack installed about 3 feet from actually being on stage and less than 15 feet from the audience. They were Loud and distracting. I tried building a box around them but they began to do all kinds of crazy things. I immediately removed the box because they were clearly getting too hot. All problems went away again.

[renegadeblack]

Yes, it was me that has the same rack as you.

Also, the fan on top of the dimmers is angled, so a box that goes straight up will obstruct the air flow either way.

[MillburyAuditorium]

(Sorry been away a while)


That's odd Renegade, ours seems to be flat, but either way, we have never had any problem with over heating in the last 6 years.

[teqniqal]

If your airflow is blocked, you can have so many issues. We actually had our CD-80 rack shut down because it was too hot, some dude from the cleaning crew put some tables blocking the air intake, and the heat sensor tripped during a very high profile show. So if for no other reason, move whatever it is blocking the airflow because your show is then in danger, also you have a fire hazard, and its bad for the dimmers, etc. Just bad all around. And if your lights are close enough for burning any soft goods, why? That is way too close. Probably looks silly too, I imagine that if a source 4 is too close to a teaser it might bleed thru, especially if its old (the teaser). Anyhow, thats an odd system, and i like the DMX-HVAC

Dimmer Racks are considered "Panelboards" as far as the National Electric Code (NEC) is concerned, and the space 42" deep directly in front them must be kept clear at ALL times. No chairs, No boxes, No tables, No Props, No Scenery (see a pattern here?). All too frequently I find Fire Extinguishers, Fire Alarm Pull Stations, Circuit Breaker Panels (Panelboards), Fire Hose Cabinets, Fire Alarm Control Panels, and the Fire Curtain Release Station(s) blocked by 'junk'. This is bad JuJu. Do Not Do This. Install Signage on the face of the device (or adjacent to it) AND on the floor infront of it that clearly informs people that it is a violation of the Life Safety Code (NFPA 101) to place anything there. Black and Yellow Glow-in-the-dark marker tape can also be helpful to mark the wall and floor around / in front of these items .

Alsoof interest is the configuration of the dimmer rack CPU ("brain", "Control Module", etc.) with regard to the houselights circuits. Any time that the auditorium is occupied (by even one operson) the houselights must cast a minimum of 1/2 foot-candle on all of the aisles and egress paths. Many CPU's can be programmed to place a lowere level limit on individual dimmer circuits. Regardless of how cool a total balck-out may be, or how badly the director or lighting designer wants it, you cannot do this. Period. End of sentence. If you have access to the houselight dimmers as part of your console functions, or even if they are a separately controlled system, you need to have this function properly implemented so that unless the Dimmer Rack is completely turned-off, the houselights won't go to total black. If you cannot figure-out how set this up, contact an expert and pay them to do it.

This also relates to the 'feature' mentioned ealier where the HVAC system came on everytime the dimmer system was activated. Yes, the dimming system was deliberately tied to the HVAC system so that air circulation would be maintained during periods of occupancy. Building Codes require an exchange of air. As to the 'meat locker' conditions, it sounds like the building engineer needs to make some adjustments. They probably made some erroneous pre-construction estimates about the number of bodies that would occupy the room, and how much heat they would generate. This can be fixed, and should be, as we all want to be 'green'.

The wooden box placed upon the top of the dimmer rack to divert the exhaust fan noise upward should also be reviwed by the HVAC engineer. Wood is combustable and has no place around hot electrical equipment, particualrly on or around a theatre stage. That is why air ducts are made from sheet metal and have non-combustable acoustical linings. It would cost very little to have a few feet of metal duct with an acoustical liner facricated and installed in a manner that would direct the noise and exhaust air upward. Sorry to hear you were the victim of yet another idiot that placed the dimmer rack(s) on stage. It's all too common that someone that just doesn't 'get' theatre to design the systems for it.

As to the hot stage lights potentially burning a hole in the drapes - yes, this is a very real danger. Most stage drapery companies fabricate and sell fire-proof heat shields to be installed on the back-side of the border drapes and legs. This does not help the front side, but the lights are usually behind a border, not directly in front of one. If your masking plan and stage electrics are not arranged this way, then is should be reviewed and reconfigured as this would likely be a poor design.

As the other responder said, too: Have the fire proofing on the drapes checked. If you can find the tag on the drape, it should show the date of manufacture (as opposed to the date of sale or installation) and possibly the name of the fire retardant applied. If it does not, then ALL bets are off. When purchasing new drapes: INSIST that each drape has a unique serial number, and that the tag shows the date of treatment, the chemical process applied, and the recommended service / reapplication interval. It is also common to have them leave a set of fabric test trips sewn to the back of the curtain - typically 5-10 strips that are 10-12" long x 1-2" wide, minimum. More are better so they can be tested annually for the life of the soft goods.

[derekleffew]

... the houselights must cast a minimum of 1/2 foot-candle on all of the aisles and egress paths. ...

Erich, while I can certainly agree with and appreciate the need for minimum egress lighting levels, I can't believe there's a requirement that the illumination MUST come from auditorium ceiling houselight fixtures. Would not aisle lights, mounted on the ends of seat rows, or embedded in the finished floor, serve this purpose? I can't recall ever being in a theatre-type venue (except for a cinema) where the houselights could not be dimmed to 0%.

[STEVETERRY]

Erich, while I can certainly agree with and appreciate the need for minimum egress lighting levels, I can't believe there's a requirement that the illumination MUST come from auditorium ceiling houselight fixtures. Would not aisle lights, mounted on the ends of seat rows, or embedded in the finished floor, serve this purpose? I can't recall ever being in a theatre-type venue (except for a cinema) where the houselights could not be dimmed to 0%.

I would agree with that view--NFPA 101 (Life Safety Code) Section 7.8 "Illuminating Means of Egress" does not specify which fixtures must provide the illumination.

The required illumination level is 0.2 footcandles during performances in assembly occupancies. This illumination can even be provided by exit signs per section 7.8.1.5, providing the levels of 0.2 fc of 7.8.1.3 (3) are met.

Unless there is some other code at work here, NFPA 101 will clearly let you dim the houselights to zero, as long as you have 0.2 fc from some other source.

In addition, section 7.8.1.3 (4) says "The minimum illumination requirements shall not apply where operations or processes require low lighting levels". That is how it was allowable to turn off the exit signs in the Shubert Theatre during the first 15 seconds of the Broadway production of "A Chorus Line", while the cast came on stage during a real blackout.

What did I miss?

ST

[derekleffew]

...In addition, section 7.8.1.3 (4) says "The minimum illumination requirements shall not apply where operations or processes require low lighting levels". That is how it was allowable to turn off the exit signs in the Shubert Theatre during the first 15 seconds of the Broadway production of "A Chorus Line", while the cast came on stage during a real blackout. ...

A practice that continues, apparently, with the current national tour:

I just did the A Chorus Line National Touring Company, and for the initial reveal of the mirrors, they asked and I got permission from the Fire Marshal to turn off the aisle lights for the first black out, lasting no more than 30 seconds. At that same time we had ushers cover the exit signs with placards.

Caution to readers: These are cases of professional productions and venues, with all possible safety procedures in place, and PRIOR PERMISSION and APPROVAL from the AHJ.

[STEVETERRY]

Dimmer Racks are considered "Panelboards" as far as the National Electric Code (NEC) is concerned, and the space 42" deep directly in front them must be kept clear at ALL times. .

Erich--

A dimmer rack is generally considered a dead-front switchboard. I think NEC Table 110.26(A)(1) Condition 1 for 151-600V applies, which would mean 36" clearance rather than the 42" you mentioned.

Condition 2 would require 42" space, but modern dimmer rack design makes it highly unlikely that there will be exposed live parts during inspection or servicing--the rack will be de-energized. This is especially true in light of the arc-flash requirements of NFPA70E.

Was there a reason I missed that you specified 42"?

Cheers

ST

[teqniqal]

I would agree with that view--NFPA 101 (Life Safety Code) Section 7.8 "Illuminating Means of Egress" does not specify which fixtures must provide the illumination.

The required illumination level is 0.2 footcandles during performances in assembly occupancies. This illumination can even be provided by exit signs per section 7.8.1.5, providing the levels of 0.2 fc of 7.8.1.3 (3) are met.

Unless there is some other code at work here, NFPA 101 will clearly let you dim the houselights to zero, as long as you have 0.2 fc from some other source.

In addition, section 7.8.1.3 (4) says "The minimum illumination requirements shall not apply where operations or processes require low lighting levels". That is how it was allowable to turn off the exit signs in the Shubert Theatre during the first 15 seconds of the Broadway production of "A Chorus Line", while the cast came on stage during a real blackout.

What did I miss?

ST

My apoligies for not being more clear. When I said "houselights" I meant it inclusive of any supplementary aisle lighting. "Houselights" are a system of fixtures, not just the ones in the ceiling. It can also include wall sconces, cove lights, emergency lights, exit lights, etc.

The reason I quote the 1/2 foot-candle level is because 0.2 (1/5) fc is the minimum requirement, and most light meters that people use in theatres do not have NIST traceble calibration, and may not be that accurate to begin with, so to err on the high side tends to ensure that you have not erred on the low side. Then there is the effect of lumen depriciation, burned-out lamps, dirt, and other human factors that have to do with old people not being able to see well in low lighting conditions.

As noted elsewhere, just because people do it doesn't mean it is legal. I think that if you run the idea of doing something illegal past your school's legal department, you will usually get a resounding "NO", so why bother? (doing the illegal thing that is, not asking the legal department). With regard to section 7.8.1.3 (4), I think we run enough risks working in dark theatres that it's hardly "worth it" to put the audience in peril for such an effect. At least I wouldn't want to have to sit in courtroom and explain it to a jury. I've got better things to do with my time.

-Erich Friend
Teqniqal Systems, LLC

[MillburyAuditorium]

All of our exits have the lit EXIT signs on them.

[teqniqal]

Erich--

A dimmer rack is generally considered a dead-front switchboard. I think NEC Table 110.26(A)(1) Condition 1 for 151-600V applies, which would mean 36" clearance rather than the 42" you mentioned.

Condition 2 would require 42" space, but modern dimmer rack design makes it highly unlikely that there will be exposed live parts during inspection or servicing--the rack will be de-energized. This is especially true in light of the arc-flash requirements of NFPA70E.

Was there a reason I missed that you specified 42"?

ST

No, you didn't miss anything as far as the NEC applies. The reason I use the 42" rule is that frequently there are other panelboards that meet that requirement in and about theatres, so I use the broader definition as a blanket dimension. Why confuse people with "this is 36, that is 42" ? An extra 6" of clearance is typically a good thing anyway, as people will always try to crowd things right-up to the limit.

Also remember: the 36"/42" rules are a minimum requirement, not an absolute distance. Another reason for the 42" specification is that the 36" rule is frequently misinterpreted as being measured from the wall, not from the face of the dimmer rack / panelboard, so this assures a bit more clearance (even though they will come-up short in the long-run).

And lastly, I like a little more room to work around electricity - so what is the harm in laying claim to a little more real estate?
-Erich Friend
Teqniqal Systems

[ptero]

Regarding how many dimmers are in a 96 rack:

I once ran across a newly installed ETC 96 rack in a high school. They were having trouble making some fixtures work when hung and plugged into a numbered outlet. Turned out they wired the place for 96 dimmers, there were 96 numbered outlets throughout the theatre, but they loaded the rack with 24 dual modules for a total of 48 working dimmers.

So, any of the 96 outlets could be used, BUT modules had to be shuffled around in the rack to 'power' the desired outlets. The Dimmer One position in the rack = Outlet #1 in the theatre. But without a module - no workie.

With a module in place to drive #1, #2 was also drivable, due to the 2 dimmers/module deal. That is - drivable separately, assuming the softpatch on the console was patched to control them separately with separate Channels.

When hanging a plot, they had to pay attention to using outlets in pairs. Then go to the rack and move modules accordingly. Or, not use all 48 dimmers. Oy. They sort of ended up with the modules in every other slot as a basic setup. Then they'd shuffle them as necessary for specific needs.

Boy, I hope that makes sense.

I imagine someone was thinking of future expansion by way of just having to purchase modules to fill it up in the future. But the basic paperwork and manual on site made no mention of this.

ANYWAY, look for all those breakers. Make sure the rack is indeed full 48 Modules/96 Dimmers and not a bunch of filler airflow blanks. Because there is a numbered outlet out there doesn't mean it's gonna work.

[kenneth]

My drama teacher has told me that we are getting some new digital dimmers - what's the difference between the new (tiny little box) of digital ones and the old big huge ones?
Thanks
K

[icewolf08]

My drama teacher has told me that we are getting some new digital dimmers - what's the difference between the new (tiny little box) of digital ones and the old big huge ones?
Thanks
K

The difference is mainly in control. Newer dimmers take a digital control signal, where older dimmers used and analog control. The other major thing you will notice is that newer dimmers are smaller. The technology has advanced such that we can fit all the electronics into a smaller form factor.

[kenneth]

The difference is mainly in control. Newer dimmers take a digital control signal, where older dimmers used and analog control. The other major thing you will notice is that newer dimmers are smaller. The technology has advanced such that we can fit all the electronics into a smaller form factor.

Ace. Apparently we won't use the huge toilet-handle style switches too?
Thanks

[renegadeblack]

Ace. Apparently we won't use the huge toilet-handle style switches too?
Thanks

Nope, you'll be using something different and that will be much easier to use. Something like the ETC Element, or if your school is cheaping out and doesn't like you, the Innovator. If you find yourself with an Innovator, save your sanity and quit now... I wish I had...

[Tex]

If you find yourself with an Innovator, save your sanity and quit now... I wish I had...

Now, now. There's no need to scare the poor guy.
I have an Innovator, and while it's not what I would have chosen, it's been quite servicable so far. I'm even using it with intelligent lights and I haven't punched a wall or pulled out any hair (not even my own.) The only problems I've had have been (L)user created.
You'll be OK, even if you do get an Innovator.