Sustainable Building Technical Manual - Etn-presco.net

❑ In highly sound-sensitive areas, perform a full analysis of room geometry, volume,and surface finishes to predict reverberation time.This type of analysis is necessary in boardrooms, auditoriums, and similar spaces toidentify measures that attain the desired reverberation time. Where natural speech projectionis of importance, such as in classrooms and lecture halls, strategic placement ofsuitably reflective surfaces enhances speech projection to the rear of the facility.❑ Use acoustical ceiling products and carpeted floors.Sounds generated by general office functions are typically controlled by acoustical ceilingproducts and carpeted floors. More critical spaces such as conference rooms andaudio-visual facilities require acoustical wall treatment.❑ Determine when additional acoustical treatments are needed to increase soundabsorption within a given spaces, and in those cases, consider using:– Acoustical ceiling tiles;– Fabric-wrapped wall panels; and– Spray-on acoustical treatments.❑ Select appropriate ceiling tiles based on ceiling sound transmission class rating.Ceiling materials are specified according to their level of “softness” to absorb sound in agiven space and according to their barrier properties as denoted by their ceiling soundtransmission class (CSTC) rating. The higher the CSTC value, the greater the material’sability to prevent sound transmission. Typical mineral-fiber ceilings are rated CSTC-35 to39, while fiberglass systems are rated at the lower performance level of CSTC-20 to 25.❑ Avoid using acoustic materials that may adversely affect indoor air quality.Some sound insulation products can absorb dust and other substances that may laterbe emitted. These substances can become airborne and move through the HVAC system,potentially becoming a health hazard. The use of encapsulating products toaddress this problem may interfere with acoustic performance. (See Chapter 13,“Indoor Air Quality,” for more information on materials and IAQ).Mechanical Issues❑ Determine what mechanical equipment has been selected for the structure, fore x a m p l e :– Cooling tower;– Chillers;– Air-handling units;– Exhaust fans;– Heat pumps;– Fan coil units; and– Variable-air-volume boxes.❑ Consider what manufacturers report as the sound power and pressure levels forthe selected models.❑ Determine whether a mock-up test of specific project conditions is necessary topredict actual noise levels or to test new, previously untested equipment.❑ Determine whether the equipment is suitable for the usage from an acousticstandpoint.❑ Determine if noise levels of mechanical equipment meet the project’s acousticalcriteria.❑ Recommend improvements to acoustic conditions related to the mechanicalequipment, if necessary.such as the following:– Relocate the equipment to a less sensitive space;– Install or increase lining within the ductwork;– Include sound attenuators (silencers) within the system; or– Re-select a given piece of equipment.