The barrier is to be installed 10’ from the loading dock. In order to meet the guests’ expectations, it is agreed upon that a 7 dB drop at the 500 Hz truck beeper frequency range will be acceptable. The hotel owner is making noise complaints due to the early deliveries and upset guests. As discussed earlier, a reduction of 7 dBA is significant and reducing by 10 dBA represents halving the perceived sound level.Įxample: A truck backs up to loading docks for delivery at 6 AM every morning, near a hotel. This is a combination of several factors – the thickness of the wall, the frequency of the sound, and how much needs to be blocked. Exterior Noise PropagationĪ common question that acoustic consultants have to solve is how high a wall needs to be to block the sound.
#Noise mapping nc windows
This explains why exterior windows should always be improved prior to investing any STC improvement in exterior walls. The composite STC may be calculated as follows:Įquation: Composite TL = 10log (SumS/Sum) This results in the majority of sound transfer passing through the glass. Similar to 1% rule, sound follows the path of least resistance. However, the actual composite STC of the wall is 23. You may assume that the STC of the described wall is 30 (half way between 20 and 40). The STC is weighted heavily toward the lower of the two numbers.
For instance, if a wall is 50% brick and 50% glass, then the composite STC of the wall will fall between the STC of a brick wall (approximately 40) and the glass (approximately 20). Noise Criteria Level for Hospital Spaces per FGI Guidelines Air Speed to Achieve Noise Criteria Levels Composite Noise CalculationsĬomposite Sound Levels are calculated by combining the STC of the individual components. NC levels are limited by a number of factors, including distance from the air handler and other noisy system components, equipment selection, and speed of the air through vents and ducts. This is common in theaters and cinemas where background noise may impair the ability of attendees to enjoy the show/performance. In certain spaces, it is important to reduce this NC level so that sounds are clearly heard.
NC, or Noise Criteria, is the background noise level attributable to HVAC and other background mechanical noises.
0 kommentar(er)
