Revised Criteria for Noise in Buildings
About: This article is published in Noise Control.The article was published on 1957-01-01. It has received 76 citations till now. The article focuses on the topics: Noise.
Citations
More filters
TL;DR: The room criterion (RC) method, which measures background noise in the building over the frequency range of 16-4000 Hz, and the QAI, which is useful in estimating an occupant's probable reaction when the system design does not produce optimum sound quality, are concluded.
Abstract: Noise may be defined as any unwanted sound. Sound becomes noise when it is too loud, unexpected, uncontrolled, happens at the wrong time, contains unwanted pure tones or unpleasant. In addition to being annoying, loud noise can cause hearing loss, and, depending on other factors, can affect stress level, sleep patterns and heart rate. The primary object for determining subjective estimations of loudness is to present sounds to a sample of listeners under controlled conditions. In heating, ventilation and air conditioning (HVAC) systems only the ventilation fan industry (e.g., bathroom exhaust and sidewall propeller fans) uses loudness ratings. In order to find satisfaction, percent of exposure to noise is the valuable issue for the personnel who are working in these areas. The room criterion (RC) method has been defined by ANSI standard S12.2, which is based on measured levels of in HVAC systems noise in spaces and is used primarily as a diagnostic tool. The RC method consists of a family of criteria curves and a rating procedure. RC measures background noise in the building over the frequency range of 16-4000 Hz. This rating system requires determination of the mid-frequency average level and determining the perceived balance between high-frequency (HF) sound and low-frequency (LF) sound. The arithmetic average of the sound levels in the 500, 1000 and 2000 Hz octave bands is 44.6 dB; therefore, the RC 45 curve is selected as the reference for spectrum quality evaluation. The spectral deviation factors in the LF, medium-frequency sound and HF regions are 2.9, 7.5 and -2.3, respectively, giving a Quality Assessment Index (QAI) of 9.8. This concludes the QAI is useful in estimating an occupant's probable reaction when the system design does not produce optimum sound quality. Thus, a QAI between 5 and 10 dB represents a marginal situation in which acceptance by an occupant is questionable. However, when sound pressure levels in the 16 or 31.5 Hz octave bands exceed 65 dB, vibration in lightweight office construction is possible.
8 citations
Cites background from "Revised Criteria for Noise in Build..."
...5 to 250 Hz are more than 5 dB above the RC rating curve, and a hissy imbalance exists if any of the levels in the octave bands with center frequencies from 1000 to 4000 Hz are above the RC rating curve by more than 3 dB.[7]...
[...]
01 Jan 2006
TL;DR: In this article, the authors examined background and octave band noise levels collected from a combination of 79 unoccupied urban public and private school classrooms in Hawai'i (island of Oahu).
Abstract: This study examined background and octave band noise levels collected from a combination of 79 unoccupied urban public and private school classrooms in Hawai‘i (island of Oahu). Noise measurements were obtained from fi rst, second, and third grade classrooms and room characteristics were determined for each classroom tested. Measurements were obtained in decibels with the sound level meter weighting switch in “A” position (dBA) and octave band noise spectra were collected to determine Noise Criteria (NC) ratings. Results indicated mean noise levels of all classrooms were above the 30 dBA criterion recommended by the American Speech and Hearing Association (ASHA, 1995), the 20 dB NC rating recommended by the American Speech and Hearing Association (ASHA, 1995), and the 35 dBA criterion recommended by the American National Standards Institute (ANSI, 2002) for educational settings. These fi ndings are discussed.
8 citations
Cites background from "Revised Criteria for Noise in Build..."
...Standard NC contours, fi rst described by Beranek (1957), take into account the equal loudness contours of Fletcher and Munson (1933) to accurately refl ect the listening experience....
[...]
01 Jan 1980
8 citations
Cites methods from "Revised Criteria for Noise in Build..."
...A single-number method of providing information on the spectrum content employs Noise Criteria Curves and the resulting NC num bers (96)....
[...]
TL;DR: In this article, the need for ease of communication, privacy and freedom from annoyance determine the acoustic requirements for an office, and in particular they lead to the control of the background noise in some offices this means keeping noise levels down but in others it is necessary to introduce background noise to maximize privacy and to minimise annoyance.
8 citations