What Goes Into Your Plenum?
Ironically, as AV systems have become more prevalent, many of them are better off disappearing altogether. The trend in videoconferencing systems, for instance, is to create a solution where the technology itself is invisible (save for the flat-panel displays, of course).
In a vaguely ironic twist, as AV systems have become more prevalent, many of them are better off disappearing altogether. The trend in videoconferencing systems, for instance, is to create a solution where the technology itself is invisible (save for the flat-panel displays, of course).
But finding a good place to hide AV components and accessories can be tricky. Say you're working on a conference room or classroom and you can't find the right spot for an audio amplifier. You already know where the cables go: in the plenum area, typically between a structural and drop ceiling, or under a raised floor. Other AV equipment can go there, too–provided its plenum-rated.
Major AV manufacturers have already begun offering plenum-rated products other than cabling. A couple years ago, Chief Manufactur-ing (www.chiefmfg.com) began shipping pre-installation box acces-sories that had passed Underwriters Laboratories (UL) standards for safety in plenum spaces. A company called Roemtech of Dallas (www.roemtech.com) has long been selling its Plenum MixerAmp PMA240 through pro AV dealers such as CCS Presenta-tions and The Whitlock Group, according to the company's Web site.
In a nutshell, when you're looking for AV gear that you can hide in air-handling spaces, they need to meet environmental and fire protection regulations. Plenum-rated cable, for example, complies with National Electrical Code requirements for use in air circulation areas of a building.
Other products are considered plenum-rated when they pass UL 2043 tests for heat and visible smoke release from products installed in air-handling spaces. Tested products are subject to an open-flame ignition source and evaluated using a product calorimeter. The test measures the rate of heat and smoke release from the burning products to determine whether they meet the requirements for fire-resistant and low smoke-producing characteristics in accordance with the provisions of the National Electric Code, NFPA 70 (www.nfpa.org).
Extron Electronics (www.extron.com) sells various plenum-rated power amplifiers, including the MPA 181T and MPA 122, as well as IP Link Ethernet control interfaces (perfect candidates for disappearing into plenum spaces). The company also says that by using its Flexible Conduit Adapter Kit, products like its PS 123 multiple output power supply conform to plenum specs.
Crestron (www.crestron.com) this year rolled out a slew of new Green Light environmental controls. Among them, the CLS-EXP-DIMU universal dimmer expansion module is plenum-rated. It works with Crestron's iLux lighting control system and can auto-detect dimmable load types. Though it can be wall-mounted, why bother?