In building or renovating a performing-arts venue, HVAC (heating, ventilation, and air-conditioning) and sprinkler systems can be problematic if not carefully planned for and watched throughout construction to make sure that changes, for whatever reason, don't have a negative impact on your needs for future productions. Working out space for sound cables, electrics cables, DMX, Ethernet, and expansion in the future must be done while saving enough space for all the mechanicals needed. Why does it seem like everyone is always fighting for space when it looks like there was enough crucial space on stage and in the grid, and enough front-of-house lighting positions during the design phase?

Sprinkler pipes are part of the mechanical engineer's work, including water, sprinklers, sewage, and steam (if that's the heat source). In New York, you can buy steam directly from Con Ed. This can be an easy space-saving method of heating without needing a large heating plant in your building, but that's not always the case in some cities. I'm sure you've been to theatres and other entertainment venues where you ask: Why is there a column there, why is there a catwalk there, why is there an air-conditioning duct there, or why isn't the stage air conditioned? Proper planning in renovating or building a new performance space can help avoid these problems.

In the meantime, your acoustician must keep track of sound isolation and other acoustic requirements for performance and rehearsal spaces. I'm sure you've been in buildings that have banging radiators, blowing air noise, and breezy spaces. To achieve a quiet space, you want to use a forced-air system that will deliver low-velocity and high-volume air, which generally means very large ducts. During schematic and design phases of any renovation or creation of a new space, the sprinklers and the HVAC ducts must be given ample space.

Keeping Cool

Asif Syed, a partner at AKF Engineers, is an engineer who worked with me on the renovation of the Biltmore Theatre in NYC. When it comes to air conditioning, he presents the pros and cons of displacement and conventional systems: “Displacement is supply from the bottom and return from the top, while conventional is supply from the top and return from the bottom. Displacement is useful in theatres,” he says. The difference is in the temperature between the two systems, as conventional supplies 55° air, and with displacement, you supply 65° air. The lights in a theatre also play an important role. “In a conventional system, you have to cool the air past the lights; in the displacement system, the air in the ceiling does not matter because you're cooling from below,” Syed points out.

“There are a number of ways to use a displacement system,” he continues. “You can put it in the rise of each step, or you can blow it up from the floor. Some seats are built so that you can blow it out the standard of this seat. Or you could put it in front of each seat more like a car air-conditioning system.” Syed cites Carnegie Hall in NYC as an interesting historic example. “The cooling system was a grate in the sidewalk; an ice truck would dump slabs of ice into a vault,” he says. “Fans would blow the cool air under the seats cooling the house, and there was a fan off the top of the roof, which exhausted the hot air out into the open air.”

Another issue is focusing on where the load is, the people. “Each person creates a plume of heat around themselves due to body heat,” says Syed. “The contaminants generated by each person rise up and do not contaminate the rest of the area in a displacement system, where they don't go into the other person's plume. In a conventional system, you mix up all the air and make a big soup that's very hard to regulate, and here the contaminants mix and people breathe a soup of mixed air.

“Part of this plume that people exhaust contains a lot of moisture. You need to get rid of the moisture in the air to return it as cool air,” he continues. “To do this, you need to cool the air, and by cooling only the right amount, you can save energy. You can save 15 to 20% of energy by using a displacement system, where you have a 10° difference in the air you have to cool between 55° and 65°. The lifecycle of an AC unit is 20 years, which is a lot of energy-saving.”