工作場所音場模擬軟體預估可行性之探討

The Application of the Sound Field Simulating Technique on Noisy Factories

工作場所音場模擬預估模式是將噪音環境之噪音源與工廠邊界條件建構於音場模擬軟體，利用該軟體推估作業場所內之音場分佈，除可由模擬結果瞭解勞工噪音暴露音壓級，實施噪音危害保護管理計畫外，並可依各噪音改善方案對應不同之噪音源特性與工廠邊界條件等參數，進行改善後音場模擬，評估各方案之成效，提供事業單位執行廠房噪音控制之參考。本研究係採用音場模擬商用軟體（RS 與RN二套音場模擬軟體）進行試驗，研究初期於邊界條件簡單且易控制之音響實驗室與會議室內進行音場模擬技術準確性測試，結果顯示模擬值與現場量測值之差值約於1dB左右，該技術可應用於室內音場分佈之推估。另選擇一噪音工廠進行音場模擬，探討該模擬技術於複雜噪音環境之適用性，因作業工廠之邊界條件較複雜，模擬結果顯示於該工廠推估有2.3-5.2dB之誤差。為進一步瞭解該技術於工程控制成效評估之可行性，針對噪音源防音罩打開與蓋上進行音場模擬，模擬結果防音罩約可降低2dB之功效。該模擬技術應用於複雜廠房，於定量上雖有5dB左右之誤差，但若配合各控制方案對應之參數變動進行成效模擬，結果可作為事業單位選定噪音改善方案之參考。

Noise Control Prediction Model uses sound field simulating techniques to collect data on environmental variables of noise work site and on noise source, then uses computer software to analyze data collected and makes simulated sound field prediction. The model can also be used to estimate the effectiveness of each noise control proposals. The results will serve as a reference for factories when implementing noise control projects. Using computer programs (RS and RN) to evaluate the sound field in this study. our institute has started to analyze the factors under a simplified and controllable lab environment using the simulating sound field software and techniques. Since the difference between predicted figures and on-site measurements in the study is less than 1dB, we expect to use the tested model on real work sites effectively. We choose a noisy factory to perform sound field simulation. The test result from the tape factory shows that RN came out best with the RMS of 2.3dB between predicted figures and field measurements. The RMS of sound pressure between predicted figures and actual measurements does not exceed 5dB. In addition, the comparison on the contour sound maps indicates that the simulation result of RN produces a similar sound map to the map drawn from actual measurements. We can use this technique to predict the effectiveness of noise control proposals and the results can serve as a reference.