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Planning Auditorium Lighting Wha

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					                                                                 ACOUSTIC DIMENSIONS
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Planning Auditorium Lighting
What should you consider for remodeling or new construction?
by Russell Reid

Light. It is the primary sense in humans and a necessary ingredient for life. Without it our existence on this
planet would be impossible. The cycle of night and day drives our body’s circadian rhythms. We seldom think
about light until it is absent. We flick a switch, or open a blind to let the sun shine in without a care to how the
light that we call into our lives is generated or how it affects us, until the power goes out, or we are in the
wilderness at night. Then we are reminded as to how important light is to us. Humans truly began to take
control of their environment when they began to control light. Then the night, our enemy, wasn’t as dark and
the shadows were not so scary. We could work when we wanted and where we wanted. Our control of light
has become much more sophisticated since then. We have many ways to generate light, many ways to
control it. We can change the color, intensity, direction, and quality. But how do you choose what is best for
the environment? This question becomes very important when you have to choose the systems for a
performance or service facility where the needs of the organization can be complex and ever changing.


Start with a program.
Just like a computer is just a pile of electronics without software, a facility is just a pile of bricks without a
program. The program defines who you are, what you want to do in the space, what the basic requirements
are to accomplish your goals, and a general description of what capabilities that the lighting systems need to
meet the program. The program should address things like, what types of events are going to happen in this
room? How often will these events occur? How much control is necessary of the lighting in this room to meet
the needs of those events? Is there a clear distinction between stage and audience? Are we going to
broadcast these events or are they just for live consumption. In addition, a program should always define
limitations, if any, on the facility and systems. These limitations can include items such as budgetary
limitations, facility limitations, personnel limitations, etc. Generally you should include anything that will affect
your choices when it comes time to design the systems. A clearly articulated program, written down, is a
fantastic tool for guidance. When you get lost in the complexities of fixtures, control systems, and power
feeds, you can always come back to the program to find out if you have gotten off track. Or maybe you have
found out that your program was insufficient and needs to be revised. In any case a program allows you to
share your facilities needs with others to solicit opinions, criticism and guidance.


Define systems to meet the needs of the program.
Here is where things begin to get complicated. With ever more complex code requirements, ever more
sophisticated audience members, and exponentially increasing choices for fixtures and control, it has become
increasingly important to have a well-defined program to guide you. There are two basic lighting systems in
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any auditorium: The architectural lighting system, which is for lighting the audience (and often the room); and
the theatrical (or performance) lighting system, which is for lighting the stage or platform (and the performers).
While they are called out as two separate systems, and are handled by different code requirements, often
these two systems are intertwined from a control standpoint. The same dimming rack handles both sets of
fixtures, the same lighting console controls both systems, and the same operator is making choices during a
performance. However, each system requires different choices design time.


The architectural lighting system needs to meet minimum building code requirements as defined for the type of
room. This means a minimum number of foot-candles of illumination, a defined set of emergency egress
lighting, and a maximum quantity of energy used to achieve the target illuminance (defined in watts per square
foot). Once the basic code requirements are met the rest is up to the program. You can begin to see that the
system is already being forced into a specific direction. To meet minimum foot-candle requirements (not to
mention programmatic foot-candle requirements, which may be higher) for your room you need to choose
lighting fixtures that will meet that need at a given ceiling height. Once you have those fixtures laid out you
total up the watts used and divide by the square footage of the room to get the watts per square foot. If you
are over the code amount of energy allowed then you have to start over with a different fixture. Energy codes
are getting stricter every year and in every locality. Currently, it is next to impossible to meet energy codes
and foot-candle requirements in many locales without using fluorescent fixtures. The traditionally
incandescent fixture that we are all familiar with will go the way of the dinosaurs soon. Don’t get discouraged.
Fluorescent technology has come a long way from the green tinted fixtures that are familiar to us in schools
and government buildings. Today’s fluorescents come in different color temperatures, have better color
rendering, and are dimmable (within limits). Choosing a fluorescent architectural system over an incandescent
one also is cheaper to operate over time (although it is slightly more expensive to install). Fluorescent lighting
systems can use as little as 10% of the dimming of a traditional incandescent system and 25% of the power. A
fluorescent lamp will typically last 20,000 hours while an incandescent lamp will average 200 hours. This is a
definite plus for an auditorium lighting system that may be mounted in a ceiling height of up to 40 feet.


Zoning the fixtures
Once you have a fixture layout that works you need to decide how to zone those fixtures. While it may seem
simple, it actually can get quite complex. Perhaps you want to be able to turn off just the balcony lights. This
makes sense if no one is sitting in the balcony. You can scale the room down. You would definitely want to
turn off any lights that are in front of or over projection screens. Perhaps there are sconces or specialty
lighting in the room that you may want to dim separately for effect. In short, you have to look at the room, look
at your program and make some aesthetic as well as practical decisions about how the architectural lighting
will be used.




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Architectural Lighting Control
The next choice to be made is how to control the architectural lighting system. The most basic type of control
system is a simple switch. This provides you with the ability to turn the lights on and off at will. This is simple,
but not too flexible (or exciting). Complexity goes up from there. Most architectural control systems these
days allow you to zone the lighting so that you can scale the room, record lighting ‘looks’ so that you can
reproduce a particular ‘feel’ in the room, and allow for multiple control locations so that you can turn on lights
from any entrance of the room. Additional features can include: remote station lockout, 24 hour time clock,
timed macros, the ability to snapshot lighting looks from the theatrical console, etc. Once again you have to go
back to your program to assist with these decisions. Some of the questions that need to be answered are:
How many entrances need a control station? Do we need the ability to lock out those remote stations for a
performance? Do we want to be able to control the theatrical fixtures from the architectural stations? Do we
want to be able to control the architectural fixtures from the theatrical console? The list can go on. Suffice it to
say that you need to think seriously about how the room will be used and by whom. You can then define how
complex of a system you need to provide.


Dimming
We now get to the heart of any performance lighting system, dimming. Dimming technology has been pretty
stable for the last 25 years or so. Despite some recent advances and hype, in essence, all dimmers function
basically the same and accomplish the same goal. In some way, a dimmer varies the amount of voltage to a
lighting fixture in order to control the intensity of the light coming from that fixture. The two main choices that
you have are to choose either a conventional rack and outlet box distribution system or a distributed dimmer
system. Each has advantages and disadvantages.


The conventional rack and outlet box system is familiar, there are many manufacturers, and any
manufacturer’s racks can usually be substituted into an existing distribution box system. Essentially, high
amperage feeders are run to the dimmer rack, the dimmer rack distributes these feeds to individual dimmers
which are then wired in separate circuits out to the lighting positions. Every wire home runs to the dimmer
rack. This arrangement has the advantage of allowing upgrades to the dimming system over time by replacing
the racks while retaining the feeds and distribution. It has the disadvantages of requiring large feed wires to
be run to the dimmer rack location (a potentially expensive proposition), and each dimmer circuit requires
individual hot and neutral wires (grounds can be shared up to the code limit). A modern rack dimming system
eats copper like it is going out of style. With the cost of copper and labor going up each year this option gets
more expensive as time goes on.


A distributed dimming system is exactly what it says, distributed. The dimmers are located out at the lighting
hang positions. Power is fed to the dimmer locations in much smaller chunks. Typically a dimmer location is
fed with one to multiple runs of single or three phase 120/208 volt at 20 amp circuits. This power is fed from



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standard electrical panels that can also be distributed around the room. There is no need for a dedicated
equipment room. The dimmers can be mounted in a raceway, a wall panel, or on the fixture it self. A module
of two dimmers shares one leg of the circuit so you need to design in groups of two dimmers. No odd
quantities of dimmers. Also, the dimmers are split 2.4kW dimmers. Each pair of dimmers can use up to
2.4kW of power. So the maximum that you can load both dimmers at one time is 1.2kW each. This effectively
halves the power available over a conventional rack system if you have an equal number of dimmers. A
distributed system can save you money over a conventional rack system by not requiring large feeder wires,
using less individual circuit wires (3 hot, 1 neutral, and 1 ground per six distributed dimmers versus 6 hot, 6
neutral, and 1 ground for six rack dimmers) and not requiring a dedicated equipment room. Distributed
dimming systems are excellent for renovations where dimming was not originally incorporated into the
building. They are a less expensive option than conventional racks for new construction if you are willing to
compare quantity of dimmers and not quantity of wattage available. The main disadvantages are: currently
only one manufacturer makes this type of system, troubleshooting the system means that you have to go to
multiple locations to track down the problem, you need to double up on the quantity of dimmers in order to
match the wattage capabilities of a conventional rack system (thus offsetting the cost savings), and you cannot
change back to a conventional rack system to upgrade technology without tearing out the infrastructure.


Making the decision of which system to choose should be based on your facility, your budget, and your
preferences. Once again, your program can help you choose. How critical is wattage? Is this a renovation?
Would you rather go to an equipment room to troubleshoot problems or walk to multiple locations? It is highly
recommended that you visit a facility to check out both types of systems before you make the final decision.


Theatrical Lighting Control
The last decision that has to be made is what to use for theatrical lighting control. I have left this until last
because it has the most variables and is the decision most subject to personal preference. With the plethora
of lighting console options, and the universality of the DMX protocol for control, it really shouldn’t matter what
console you choose. But it does. This choice can mean the difference between an easy programming
experience and a series of regular all-nighters. At this time there are two basic types of consoles.
Conventional memory preset consoles and Moving light consoles. There are hybrids that blur the lines but this
distinction is apt for our purposes. A conventional console works under the principal of Highest Takes
Precedence, where whatever channel value is highest is what is shown on stage. A moving light console
works under the principle of Last Takes Precedence. Channel settings are tracked forward and don’t change
until altered. Conventional consoles can control moving lights and moving light consoles can control
conventional dimmers but the capabilities and complexities of each are different. Here comes that concept of
the program back into play. What do you need to do? Do you need a console that can handle 60 moving
lights or just a few? What is the skill level of the operator (s)? Do you need 3D visualization so that you can
program off line? What is your budget? Should the console talk DMX or one of the flavors of lighting network



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that are available? Is the console upgradeable to Advanced Control Network (which will one day be finalized)?
If you are unfamiliar with the console, get a demo console or visit one that is being used.


Quality and Level of Support
Finally, consider the quality of the equipment you are purchasing and the level of support that you will get from
the vendor and/or manufacturer. A lower price on equipment and installation does not mean that you will get
prompt service in the event that the system has problems. System warranties only cover fixing the problem,
not necessarily fixing the problem inside of your time frame. If you need a rack control module shipped
overnight for an event on Sunday, then there better be a 24 hour line to call for the part. Be aware that a
compromise in equipment quality to save money on day one can end up costing two or three times the money
you saved if the system fails regularly or doesn’t perform up to your expectations. Your program can help by
allowing you to define where compromises can be made and where they cannot. Forethought now can save
time, money, and headache later.




Planning Architectural Lighting                     -5-                                            11/15/04

				
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