The most common noise sources in buildings are related to Heating, Ventilating and Air Conditioning (HVAC) systems, plumbing systems, electrical systems and exterior sources. Passive Noise Control (PNC) techniques in buildings have been implemented in several ways. The aim of this work is to analyses the use of silencer to attenuate the noise in the ducts that are part of the ventilation systems in buildings, internal combustion systems, fans, gas conduction systems, boilers, etc. The main objective of a silencer is to reduce the transmission of noise, disturbing as little as possible the circulation of gas or liquid. In the first instance, the silencers are classified as reactive and dissipative, depending on whether the attenuation of the noise is produced by reflective or dissipative mechanisms, respectively. In a reactive silencer, the losses occur essentially due to the reflections of the sound waves in impedance discontinuities, such as widening or narrowing of the tube. In dissipative silencers, the flow is in contact with a large surface of absorbent material. The attenuation of the noise is then produced by visco-thermal losses in the porous material. In this work, a practical issue will be addressed with a noise reduction of 19 dBA in 60 Hz.

Practical application

Noise is a current issue in residential areas that could lead to health problems for people. The origin of these noises within buildings is very diverse, one of them is produced by ducts. Appling the PNC technique in modern building construction would be a good prevention practice. For this reason, in this project a PNC system was carried out in the ducts of a residential building, which could be used as a praiseworthy solution, avoiding problems for the inhabitants of these spaces.

中文翻译：

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建筑物中的被动噪声控制：管道系统的工程案例研究

建筑物中最常见的噪声源与供暖，通风和空调（HVAC）系统，管道系统，电气系统和外部源有关。建筑物中的无源噪声控制（PNC）技术已通过多种方式实施。这项工作的目的是分析消音器的使用，以降低建筑物，通风系统，风扇，气体传导系统，锅炉等通风系统中管道的噪声。消音器的主要目的是以减少噪音的传播，从而尽可能少地干扰气体或液体的循环。在第一种情况下，根据噪音的衰减是通过反射机制还是通过耗散机制分别将消音器分为电抗性和耗散性两类。在消音器中 损耗的产生主要是由于声波在阻抗不连续中的反射，例如管子的变宽或变窄。在耗散的消音器中，气流与大面积的吸收性材料接触。然后，通过多孔材料中的粘热损失来产生噪声的衰减。在这项工作中，一个实际问题将通过在60 Hz下降低19 dBA的噪声来解决。

实际应用

噪声是居民区中的当前问题，可能导致人们的健康问题。建筑物内这些噪音的来源非常多样，其中之一是通过管道产生的。在现代建筑中应用PNC技术将是一个很好的预防措施。因此，在该项目中，在住宅建筑的管道中安装了PNC系统，可以用作值得称赞的解决方案，从而避免了这些空间的居民遇到的问题。