Forouharmajd Farhad, Nassiri Parvin, Monazzam Mohammad R, Yazdchi Mohammadreza
Department of Occupational Health Engineering, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.
Noise Health. 2012 Jul-Aug;14(59):135-9. doi: 10.4103/1463-1741.99861.
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.
噪声可定义为任何不需要的声音。当声音过大、出乎意料、不受控制、在错误的时间出现、包含不需要的纯音或令人不悦时，就会变成噪声。除了令人讨厌之外， loud noise（此处原文有误，应为loud noise，意为“噪音”）还会导致听力损失，并且根据其他因素，会影响压力水平、睡眠模式和心率。确定响度主观估计的主要目的是在受控条件下向一组听众呈现声音。在供暖、通风和空调（HVAC）系统中，只有通风风扇行业（例如浴室排气扇和侧壁螺旋桨风扇）使用响度评级。为了获得满意度，对于在这些区域工作的人员来说，噪声暴露百分比是一个重要问题。房间标准（RC）方法由美国国家标准学会（ANSI）标准S12.2定义，该标准基于对HVAC系统在空间中的噪声测量水平，主要用作诊断工具。RC方法由一系列标准曲线和评级程序组成。RC测量建筑物在16 - 4000赫兹频率范围内的背景噪声。该评级系统需要确定中频平均水平，并确定高频（HF）声音和低频（LF）声音之间的感知平衡。在500、1000和2000赫兹倍频程频段的声级算术平均值为44.6分贝；因此，选择RC 45曲线作为频谱质量评估的参考。低频、中频声音和高频区域的频谱偏差因子分别为2.9、7.5和 - 2.3，得出质量评估指数（QAI）为9.8。这表明当系统设计不能产生最佳音质时，QAI有助于估计居住者可能的反应。因此，5至10分贝之间的QAI代表一种边缘情况，居住者是否接受值得怀疑。然而，当在16或31.5赫兹倍频程频段的声压级超过65分贝时，轻型办公建筑中可能会出现振动。
