Hamadan University of Medical Sciences Journal of Research in Health Sciences 2228-7795 10 1 2010 06 28 Evaluation of Noise Propagation Characteristics of Compressors in Tehran Oil Refinery Center and Presenting Control Methods 22 30 EN Rostam Golmohammadi Mohammad Reza Monazzam Maryam Nourollahi Ali Nezafat Samaneh Momen Bellah Fard Journal Article 2011 06 29 Background: The adverse effects of noise are well known and noise problems due to industrialization of communities are increasing over the time. Oil industries due to the process and nature of production; contain many noise sources such as compressors, turbines, and pumps, which cause excessive noise exposure. The objective of this study was to evaluate the noise characteristics of compressors in Tehran Oil Refinery and study on visible control measures. Methods: To get to the appropriate control method, procedures such as basic theories, measuring sound parameters, frequency analysis, related diagrams and noise propagation schemes due to the measurement results, equivalent noise exposure level (Leq(8h)) and exposure noise dose and technical specification of compressors are considered in this paper. Considering field and analytical re­sults, module enclosure with particular specifications (like absorbent layer, specific wall, window and door design etc.) is predicted to be the best control method. Results: Calculation results of multiple layer density of the enclosure (W = 16.5 kg/m2) and needed density for the dominant frequency of the source (W = 12 kg/m2) demonstrated that the designed enclosure satisfies the goal. Conclusion: Results of designing sandwich layers’ module demonstrated that install­ing the designed enclosure causes 20 dB(A) reduction in total sound pres­sure level of the source’s dominant frequency.