ISO 15186-3:20 02规定了一种声强方法，用于确定低频下建筑构件的消声指数和构件归一化水平差。与ISO 140-3、ISO 140-10和ISO 15186-1相比，该方法在典型测试设施中具有显著更好的再现性。结果更独立于实验室的房间尺寸，更接近体积大于300 m3的房间之间测量的值。ISO 15186-3适用于50 Hz至160 Hz的频率范围，但主要用于50 Hz至80 Hz的频率范围。 注:对于面对厚多孔吸收器的元件，推荐频率范围为50 Hz至80 Hz。 ISO 15186-1和ISO 15186-3方法的主要区别在于ISO 15186-3 源室的声压级是在靠近测试样本表面的地方测量的，而接收室中与测试样本相对的表面是高吸收的，并在声学上将房间转换成具有高于最低截止频率的几个传播交叉模式的管道。 通过ISO 15186-3的方法得到的结果可以与ISO 140-3和ISO 15186-1的结果相结合，以产生频率范围为50 Hz至5 000 Hz的数据。 对于所有频率，估计该强度方法的再现性等于或优于ISO 140-3方法在100 Hz下的再现性。 给出了与ISO 15186这一部分和ISO 140-3获得的数据的一些比较，以供参考。

ISO 15186-3:2002 specifies a sound intensity method to determine the sound reduction index and the element-normalized level difference of building elements at low frequencies. This method has significantly better reproducibility in a typical test facility than those of ISO 140-3, ISO 140-10 and ISO 15186-1. The results are more independent of the room dimensions of the laboratory and closer to values that would be measured between rooms of volume greater than 300 m³. ISO 15186-3 is applicable in the frequency range 50 Hz to 160 Hz but is mainly intended for the frequency range 50 Hz to 80 Hz. NOTE For elements faced with thick, porous absorbers, the recommended frequency range is 50 Hz to 80 Hz. The main differences between the methods of ISO 15186-1 and ISO 15186-3 are that in ISO 15186-3

1. the sound pressure level of the source room is measured close to the surface of the test specimen, and
2. the surface opposite the test specimen in the receiving room is highly absorbing and converts the room acoustically into a duct with several propagating cross-modes above the lowest cut-on frequency.

The results found by the method of ISO 15186-3 can be combined with those of ISO 140-3 and ISO 15186-1 to produce data in the frequency range 50 Hz to 5 000 Hz. The reproducibility of this intensity method is, for all frequencies, estimated to be equal to or better than that found with the method of ISO 140-3 at 100 Hz. Some comparisons of data obtained with this part of ISO 15186 and with ISO 140-3 are given for information.