- 期刊
防音教室之防音效果（航空噪音）
Study on Sound-insulation Effects of Soundproof Classroom (Aircraft Noise)
摘要
本次選擇在台北國際航空站附近，於航道下已完成防音工程之兩所國民中學的教室為測量評估對象。在教室內中心點放置一個微音器與中心點及四周各放一個微音器，對飛越上空的22班飛機（含有噴射機與螺旋槳飛機），測定L(下標 Amax)及從3.15 Hz到20 kHz之1/3八音度頻帶分析結果比較其效果；另將擴音喇叭當作音源置於教室外走廊上，教室內中心點放置一個微音器量測結果與航空器通過時，教室內中心點放置一個微音器之量測結果作比較。比較後發現當航空器通過時，在5 Hz以下、10~12.5 Hz附近及31.5~60 Hz附近與高頻12.5 kHz以上之隔音效果比較差。但將所有頻率換算為A加權時，其衰減量大約在24 dB(A)左右。若使用喇叭作音源採用Pink Noise時，對隔音比較差之頻率與實際航空機通過時所得的結果相差不多，但A權衰減量可達到約38 dB(A)-兩者之差約14 dB(A)。爾後要驗收受航空噪音影響之防音教室，最好不要使用單一喇叭做模擬音源，而採用實際航空噪音為音源比較好，且當航空器通過時，為了不妨害上課，建議防音教室內之L(下標 Amax)值不要超過55 dB(A)，同時考慮低頻部份之防音。
並列摘要
Some soundproof finished classrooms on the top floor at two Junior High Schools near landing runway of Taipei International Airport were chosen as evaluation points. Six microphones were set up, one placed in the centre of the evaluation area (the classroom) and, in the second location, one microphone was again placed in the centre of the area, with further four microphones placed in the four corners of the room. Using these two configurations, we measure the L(subscript Amax) and analyze 1/3 octave frequency, from 3.15 Hz to 20 kHz, of 22 flights (including jet planes, and propeller planes) flying over the schools. In addition to this, we installed an loudspeaker in the corridor outside the classroom to act as a simulated sound source, and compared the measurement from placing a microphone in the centre of the classroom, with those while an air craft is passing by. The results show that the soundproof effect is worse under 5 Hz, 10~12.5 Hz, 31.5~60 Hz, and high frequency over 12.5 kHz when the airplane passed by. But, if all the frequency were transformed into A-weighted, the attenuation would be about 24 dB (A). If we use a loudspeaker as the sound source and adopt Pink Noise, for the frequency with the worse soundproof effect, the noise will be similar to that produced by passing airplanes, but the A-weighted attenuation could reach about 38 dB (A)-about 14 dB (A) of difference. Afterward, while checking the soundproof classroom exposed to aircraft noise, it would be better not to use one single loudspeaker as the simulative sound source, but adopt actual aircraft noise as the sound source. And the L(subscript Amax) measured in the soundproof classroom had better not exceed 55 dB (A), for exceeding it might otherwise interfere with the teaching at the nearby high schools in the classroom. Meanwhile, we should also take into account the sound-insulation effect at low frequency.