The Madonna concert that was scheduled for tonight in Marseilles will not be going on. Something went wrong when the touring stage was being assembled, and the stage roof came apart. The falling pieces destroyed the stage and killed two workers.
It is a tragic occurrence, and everyone who works in large-format touring wants to know what happened, with an eye toward what they might do differently to be safer. In addition, it is a reminder of another one of the costs of low-efficiency lighting.
The difficulties of a stage roof occur mainly because it is so heavy. Everything about an outdoor stage has to be heavy enough to be stable if the wind blows, but the reason a stage roof is so heavy is that it supports all the lights that are above the stage. The lights, in turn, have to be heavy enough to dissipate all the heat they generate — heat that results because only a tiny fraction, perhaps 3 percent, of all the energy they use gets turned into light. The overhead lights for the stage of a large nightclub can easily be a ton — and the lights above a stadium stage are so heavy you don’t really want to think about it.
This is not just true of the stage, by the way; in almost any structure, the lighting weighs more than the wiring. Lighting fixtures take up about 1 percent of the carrying capacity of a house or a typical office building, and perhaps 5 percent in a warehouse-type building. That might not sound like much, but if it adds $250 to the cost of the structure of your house, it’s a difference you might care about.
But simplifying a structure is not just about saving money. A simpler structure is also more reliable, in the sense that there are fewer things that can go wrong. We don’t know quite what went wrong in Marseilles, but it is possible that it had something to do with the weight of the structure that was being put up, and that a lighter structure, the kind that high-efficiency lighting would allow, could pose less risk.
High-efficiency lighting is about to catch on in a big way starting in 2012. As we replace the current inefficient incandescent and fluorescent lights with high-efficiency lighting, we won’t just be using less electricity. That is reason enough to make the change, but we will also be dealing with lighting that is cooler, lighter, and easier to handle.