Theatre Design & Technology - Summer 2009 - 10

Immediate E-stops could be dangerous, as another member pointed out citing Sunset Boulevard as an example. Controlled E-stops are
permissible, and are essential for heavy loads or devices on which people are riding. Controlled E-stops are Category 1: "Category 1 is a
controlled stop with power to the machine actuators available to achieve the stop then remove power when the stop is achieved."
Dead Man's Handle. One panelist implied that he did not have a "dead man's handle" on his stage motor control equipment. Such
a device is essential where movements are triggered. (Only when pushbutton action has to be sustained by being held down while a movement takes place, as with a single motor handheld portable controller, is a dead man's handle unnecessary.) The dead man's handle is a
Category 2 stop: "Category 2 is a controlled stop with power left available to the machine actuators."
Encoder failure = movement ceases. A panelist mentioned that one of the reasons for a spotter (lookout) for moving equipment/effects is to tell the automation operator (motorized equipment/effects controls operator) to stop the motion that if an encoder fails.
However, with any properly designed motorization an encoder failure would automatically stop movement. In fact if the encoder is also
used for overspeed protection, and if failure can in any way cause an increase in speed then the design would violate provisions 7.6.1 and
7.6.2. Motor/Equipment Overspeed Protection in NFPA 79-2007.
Stage Manager v. Automation Operator calling the shots. Another reason proffered for a spotter was that the spotter can
tell the automation operator to stop movement/s if things are going awry. As a broadway stage manager in the audience pointed out, it's
entirely the stage manager's call if an effect/movement is to be stopped whilst in progress. (If the spotter sees an actual emergency then
he should immediately push the nearby E-stop - see next paragraph.)
Use of E-stops. It's essential that everybody backstage feel free to use E-stops. That's why testing all movements under E-sop before
the opening of a show is so important. Static E-stop action checks must also occur every day. A member of the audience pointed out
the acceptable use of E-stops (e.g. after an emergency) is to disable equipment while it is stationary so that quick, close inspections
can be made.
It's difficult to tell by cursory inspection whether E-stop systems meet NFPA 79-2007, hence, in my view, the need for "Principles and
Practice of Engineering" (PE) stamped drawings of and calculations for such systems. On the other hand, it's simple to check whether
electrical components or units are good to be used on stage by looking for the Ul label on them. On the exhibition floor [at the conference] there were drive cabinets with no apparent Ul label resulting from listing per the Ul 508 standard for Industrial Control Equipment.
The ESTA Standards Update session reported the publication of CEN CWA253. CEN is European Standards Committee. CWA25 is CEN
Workshop Agreement 25 lifting and load-bearing Equipment for Stages and other Production Areas within the Entertainment Industry.
Karl Ruling pointed out that as it's a foreign standard, no US governmental agency will reference it.
Therefore, there's an urgent need to develop American normative standards and recommended procedures for motorized stage equipment.
Yours sincerely,
Martin Moore, former USITT Engineering Commissioner
To the Editor,
I really don't understand some of the assertions in Jeffrey Gress' article, "The demise of Patch Panels," in the Winter 2009 issue of
TD&T.
Stanley R. McCandless' book, A Method of Lighting the Stage, was written in 1932. In it he said "...the plan encourages the technician,
the designer, and producer to use light in all its qualities within the practical limits established by the instruments." He also wrote, "...so
should each problem of lighting be approached to give the most direct expression to the dramatic visual effect.... It is to this new endeavor
that this book is dedicated."
Mr. Gress may think that "prior to the spread of Stanley McCandless' ideas in the 1960s, most production lighting was a craftsman's project." In fact, lighting designers were knowingly or unknowingly applying Mac's teaching beginning at least in the 1920s or before that, when
lighting instruments were developed to allow greater creative use of lighting of the stage. Many designers used ingenious methods before the
twenties to create lighting to support the actors and the play. Mac's ideas were not novel. Mr. Gress also states, "lighting a performed event is
in itself a creation of art. I am fortunate to have worked in the performing arts during the time when this statement became true." Mr. Gress,
I have news for you. It was true long before you were born.
If one believes (as I do ), that the lighting designer should be able to place a lighting instrument of his or her choice in every available
place in the theatre, and to be able to control (at least) its intensity and on/off state at will; and in conjunction with other lights; then it is
required to put an independently controlled outlet in each of these places. In the old days this was done by patching lighting circuits into dimmer outputs. Patching on broadway and in "Road Houses" was done as far back as the twenties and possibly earlier, sometimes using 500watt pre-set boards, and sometimes by plugging directly into pockets of 5000- or 6000-watt dimmers in the "piano boards." Early portable
auto-transformer dimmer boards had pin connector receptacles wired to the output of the dimmers. A male patch section was provided or

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2009

Table of Contents for the Digital Edition of Theatre Design & Technology - Summer 2009