Measurement of noise emitted by machines; airborne noise emission; enveloping surface method and in-duct method; fan-assisted warm air generators, fan-assisted air heaters and fan units of air handling devices
测量机器发出的噪音；空气噪声排放；包络面法和管内法；风机辅助暖风发电机、风机辅助空气加热器和空气处理装置的风机单元