period five
Review
notes
Review—Period Four
Figure 72
Period Four introduced two common methods used by HVAC equipment manufacturers to provide accurate sound data. Because sound pressure is influenced by the surroundings, the most useful sound data that can be provided for most pieces of equipment is sound power.
Sound-power levels are determined by measuring sound-pressure levels in an environment with known acoustical characteristics, and adding back any effects attributed to the surroundings. The most common method uses a special acoustical testing facility called a reverberant room.
The availability of accurate, tested sound data for HVAC equipment is vitally important to any acoustical analysis. ARI Standard 260–2001 is one example of an industry standard for rating the sound level of equipment. This standard addresses a wide range of air-handling equipment with a consistent test method. It assures accurate, verifiable sound data, and focuses on the entire air handler in all of its common installation arrangements. As with other existing sound standards, ARI 260 enables designers to make equitable product comparisons and to more accurately predict sound levels for occupied spaces.
