Abstract：

Points out the problems of undesirable effects in operation of micropunched plate mufflers in ventilating and air conditioning projects due to lack of adequate quality supervision, and explains an effective testing method for mufflers. Based on actual measurements, proves the sound attenuating capacity of the singlelayer micropunched plate muffler is very limited, and therefore its usage should be terminated. Tests the doublelayer micropunched plate muffler, the sound attenuating capacity is still lower than that stipulated in the design handbook, so its effective length shall be adequately extended to meet the demand of sound attenuating capacity.