GB/T 21231-2007 in English

《GB/T 21231-2007声学 小型通风装置辐射空气噪声的测量方法》由TC17（全国声学标准化技术委员会）归口，主管部门为中国科学院。
本标准规定了小型通风装置辐射空气噪声的测量方法。这类通风装置主要用于冷却电子、电气和机械设备，包括螺旋桨式通风机、轴流风机、翼式轴流风机、离心风机、贯流式风机、柜式鼓风机和这些装置的变型。本标准可用于冷却电子以及类似设备的小型通风装置总声功率级的测量。试验数据表明该方法对于空气流量不大于1 和风扇静压不大于750Pa的场合都是有效的。

Scope

This standard specifies the measurement method of airborne noise radiated by small ventilation devices. These ventilation units are primarily used for cooling electronic, electrical and mechanical equipment and include propeller fans, axial fans, wing axial fans, centrifugal fans, cross-flow fans, cabinet blowers and variations of these units. This standard describes the method and test equipment for the determination and reporting of airborne noise radiated by small ventilation devices as a function of the flow rate of the ventilation device and the static pressure developed by the ventilation device on the test device. This standard is intended for use by manufacturers of ventilators, manufacturers using ventilators to cool electronic equipment and similar applications, and laboratories performing testing for these manufacturers. Test results obtained using this standard are expected to be used for engineering information and performance qualification, and this method can also be referenced in the purchase specification and the contract between the buyer and the seller. The ultimate purpose of noise emission measurements is to provide data to designers of electronic, electrical or mechanical equipment that incorporates one or more ventilation devices. This standard can be used for the measurement of the total sound power level of small ventilation devices for cooling electronic and similar equipment. The test data show that this method is effective for the occasions where the air flow rate is not greater than 1 m/s and the static pressure of the fan is not greater than 750 Pa. This standard is suitable for type testing and provides methods for manufacturers of ventilation devices, manufacturers of applications such as electronics, and measurement laboratories to obtain comparable results. The method stipulated in this standard refers to GB/T 18313-2001, and provides a method for measuring the sound power level in an environment that meets specific requirements, that is, using the reverberation chamber comparison method based on GB/T 6881.1 or GB/T 14367-2006 Or the direct method of approximate free field above a reflecting surface based on GB/T 3767-1996 or GB/T 6882-1986. The method specified in this standard is applicable to ventilation devices that radiate broadband noise, narrowband noise and noise with discrete frequency components. The method specified in this standard allows the determination of the noise emission level of a single device under test. If the noise emission level of several devices of the same product series is measured, the statistical value of the product series can be determined by the methods specified in GB/T 14573.4 or GB/T 18698. Note: In actual application, vibration, turbulence, insertion loss and other phenomena will change the size of the radiated sound power, so the measurement results obtained according to this standard will be different from the measurement results after the ventilation device is installed on the equipment